Crystallographic microstructure engineering for artificial solid electrolyte interphases toward stable zinc electrode

Domain: chemistry
Published: 2026-01-08
Editorial outcome: minor_revision

Abstract
The challenge of dendrite growth limiting metal battery lifespan, despite extensive chemical composition optimizations for artificial solid electrolyte interphases (ASEIs), necessitates the development of ASEI design routes. Regulating the ASEI crystallographic microstructure offers a promising yet underexplored solution with efficacy uncertainty. Critical issue lies in what is the optimal crystallographic microstructure state. Using the ZnS ASEI in aqueous Zn batteries as a case study, here we report the effects of grain orientation and grain boundary density on the performance of Zn negative electrode. The results reveal the existence of an optimal microstructure state—predominant in-plane (111) orientation coupled with a critical grain boundary density of ~55 μm/μm2—which delivers an 18-fold lifespan extension, and over 3400 cycles with a Coulombic efficiency of 99.92% at 5 mA cm-2, surpassing the efficacy of most chemical composition manipulations. Mechanistically, the (111) orientation integrates higher electrochemical kinetics and mechanical strength. As grain boundary density increases to tens of μm/μm2, the enhancement in electrochemical kinetics coincides with compromised mechanical strength, with their trade-off delineating the critical density that maximizes electrode cycling stability. Our findings exemplify an efficient ASEI design route—crystallographic microstructure engineering.

Introduction
Rechargeable metal batteries, such as the aqueous zinc batteries, distinguished by their high energy density and cost-effectiveness, represent a vital safeguard against the impending energy crisis1–3. However, improving reliability and longevity remains a challenge4. One of the cruxes lies in the uncontrollable dendrite growth inherent to metal negative electrodes, which results in reduced Coulombic efficiency (CE) and rapid lifespan deterioration5,6. The development of artificial solid electrolyte interphase (ASEI) has emerged as a potential solution to mitigate this crux, while its efficacy and functional stability in high-rate and long-term cycling services are often limited7. As intended by such service scenes, a robust ASEI is expected to function by concurrently blocking deleterious reactions at the electrode/electrolyte interface, facilitating homogeneous ion transport, and mechanically tolerating deposition-induced interfacial fluctuations, thereby suppressing dendrite growth8,9. Meanwhile, once the ASEI is yielded by dendrite growth-induced stress, it will loss structural integrity and undergo functional degradation. These require ASEI to possess both high electrochemical kinetics and mechanical strength, rendering the optimization crucial yet highly complex.

Certainly, the design of ASEIs has garnered significant efforts10. For instance, the hybrid design of ZnF2–Ag ASEI enables the mechanistic integration of reduced nucleation and diffusion barrier, leading to enhanced reaction kinetics11. The introduction of a fluoroethylene carbonate additive in Li anode promotes the formation of a LiF-rich ASEI, which leverages the dendrite suppression effect of LiF12. Such design strategies can broadly be categorized as chemical composition manipulation-based routes, which primarily involve the introduction or doping of functional chemical species13,14. Despite certain degrees of functional improvement realized in some ASEIs, an inherent drawback of this route is the lack of compatibility among different strategies, as the applicability of a chemical additive/dopant is always material-specific. This leads to a dilemma in combining multiple strategies to further improve ASEI performance. Thus, there is an urgent need to develop more efficient and universally applicable ASEI design routes that could complement chemical composition-dependent strategies.

Most ASEIs exhibit stable crystalline structures, with two fundamental microstructural characteristics—grain orientation distribution and grain boundary density (ρGB)15,16. Crystallographic orientation has been suggested to directly affect not only ionic affinity and diffusion behavior17, but also anisotropic strength18. Given that grain boundaries (GBs) serve as both ionic transport sites and deformation agencies, varying ρGB can simultaneously regulate ionic transport kinetics and mechanical strength19,20. These insights suggest that engineering the crystallographic microstructure of ASEI may provide a unique opportunity to manage its electrochemical and mechanical properties, thereby improving the functional stability in suppressing dendrite growth. Accordingly, a possible solution to the above dilemma, i.e., an efficient ASEI design route that avoids chemical composition manipulation, is to regulate the crystallographic microstructure. Unfortunately, this route has not been widely appreciated because of the uncertainty regarding its efficacy and the absence of mechanism-based regulation principles.

Although several studies have examined the crystallographic orientation dependence on ionic diffusion kinetics and reaction activities, thus identifying the ‘optimal’ orientation of ASEIs17,21, an overlooked uncertainty remains: whether such an orientation, favorable for electrochemical kinetics, can simultaneously ensure high mechanical strength. If not, the functional stability of ASEI may also be compromised by the rapid puncturing of pre-grown dendrites22. The ρGB of ASEI, typically ranging from 0.01 to 100 μm/μm2, exhibits a possibly nonmonotonic relationship with the mechanical strength19,20,23. The critical ρGB corresponding to the highest mechanical strength can be readily identified at the transition point from the Hall-Petch regime to the inverse Hall-Petch regime24. However, this critical ρGB is generally misaligned with the requirements of electrochemical kinetics, since the latter demands as high ρGB as possible to ensure rapid ionic diffusion25. Such dependencies of electrochemical kinetics and mechanical strength on the microstructural characteristics are intertwined or even mutually exclusive, which may lead to multiple competitive and/or synergistic electro-chemo-mechanical mechanisms that complicate the regulation principles. Thus, specific issues emerge concerning the development of crystallographic microstructure-based ASEI design routes: (i) How does the crystallographic microstructure of ASEI affect its electrochemical and mechanical properties, and subsequent dendrite growth behaviors? (ii) What is the optimal crystallographic microstructure state of an ASEI, and to what extent can it deliver in enhancing electrode cycling stability?

Here, these issues are discussed in a sphalerite-phase zinc sulfide (ZnS) ASEI served in aqueous zinc batteries, as it represents one of the available ASEIs with acceptable ionic conductivity, mechanical toughness, and chemical stability, yet it remains susceptible to dendrite growth26,27. A set of ZnS ASEIs with controllable crystallographic microstructures was synthesized on a bare Zn substrate using pulsed laser deposition. Effects of the crystallographic orientation and ρGB of ASEI on the electrochemical kinetics, mechanical strength, and resultant electrode cycling stability were investigated. Two fundamentals are unveiled accordingly: (i) the ZnS (111) orientation can integrate both higher electrochemical kinetics and mechanical strength, making it the optimal orientation, (ii) the opposing trends of electrochemical kinetics and mechanical strength with increasing ρGB delineate a critical ρGB,c ~55 μm/μm2 that maximizes cycling stability. The ZnS ASEI with such an ‘ideal’ microstructure, featuring predominant in-plane (111) orientation and ρGB,c, yields an 18-fold lifespan extension in symmetric cells and up to 3400 cycles with a 99.92% CE at 5 mA cm−2. Such efficacy rivals, or even surpasses that achieved by chemical composition-dependent strategies, proving an efficient ASEI design route—crystallographic microstructure engineering.

Results
The optimal crystallographic orientation
Density functional theory (DFT) calculations were performed to compare the Zn2+ adsorption behaviors among ZnS(111), ZnS(220), and ZnS(311) crystal facets (Figs. 1a, S1), as these facets exhibit relatively high adsorption propensities28. Zn2+ adsorption on Zn(002), which is the most favorable adsorption facet in the zinc system, was considered as well29. Multiple potential adsorption structures were analyzed to identify the site with the lowest adsorption energy, i.e., the preferentially anchored location of the zinc ion, for each facet. In comparison (Fig. 1a), the ZnS (111) facet displays the lowest adsorption energy (−3.57 eV) and the highest density of the active adsorption site. Meanwhile, a more pronounced differential charge density distribution is observed on the ZnS (111) facet, indicating a strong interfacial interaction with Zn2+. These results suggest that the ZnS (111) facet exhibits the highest Zn2+ affinity and Zn2+-ASEI interfacial stability compared to other facets, highlighting its good electrochemical kinetics.

The polycrystalline nature of commercial Zn electrodes makes it difficult to grow a large-scale single crystal of ASEI with the designated orientation. Here, thus, to systematically examine the impact of preferential ZnS(111) orientation on the physicochemical properties and cycling stability, the pulsed laser deposition technique is employed to synthesize ZnS ASEIs with controllable (111) texture intensity and ρGB. The synthesized samples are named using the ZnS_x_ρ nomenclature, where x represents the (111) texture intensity, categorized as weak texture (WT), moderate-intensity texture (MT), or strong texture (ST). As shown in Fig. 1b, as-synthesized ASEIs exhibit uniform and densified microstructures, which are fundamental for enabling strong mechanical support and efficient physical isolation between the Zn electrode and electrolyte30. Notably, the ρGB (~55 μm/μm2) and layer thickness (~1.5 μm) for the ZnS ASEIs are controlled to be identical, i.e., a set of ZnS_x_55 ASEIs (Fig. S2a, b). Note that the 1.5 μm deposition thickness was chosen to ensure adequate mechanical stiffness and fast ionic transport31. X-ray diffraction patterns reveal that the ZnS_ST_55 exhibit the highest in-plane (111) texture intensity, characterized by a high (111) peak yet negligible (220) and (311) peaks (Fig. 1c). The (111) texture weakens in ZnS_MT_55 ASEI and further in ZnS_WT_55 ASEI. The corresponding (111) pole figures are shown in Fig. 1d. Figure 1e presents the high-resolution atomic image of ZnS_ST_55 ASEI. Obviously, Zn atoms exhibit a hexagonal arrangement, with the lattice distances of 3.83 Å and 3.29 Å for the (1 1 0) and (11 2 ) facets, respectively, confirming the presence of an in-plane (111) orientation as well. This set of ZnS_x_55 ASEIs isolates the (111) texture intensity as the only microstructure variable.

Building upon the disparities in ZnS (111) texture intensity, the electrode cycling stability (ECS) was comparatively investigated. Symmetric cell cycling tests reveal that the ZnS ASEI-based cells exhibit significantly prolonged lifespans compared to the bare Zn (Fig. 2a), validating the intrinsic advantages of ZnS ASEI in mitigating dendrite growth26. The Zn@ZnS_ST_55-based cell displays the longest lifespan (exceeding 1000 h), nearly 14 times that of bare Zn. However, such a lifespan-extension effect deteriorates substantially as the ZnS (111) texture weakens, a trend consistently observed irrespective of the current density or areal capacity (Figs. 2a, S3a, b). To assess the Zn plating/stripping reversibility32, Coulombic efficiencies of the asymmetric cells were measured at varying current densities as well (Figs. 2b, S3c–e). As shown in Fig. 2b, c, stronger (111) texture intensity renders more pronounced enhancements in Zn plating/stripping reversibility with high CE retention. For instance, at 5 mA cm−2, the cycling numbers of the Zn@ZnS_ST_55 cell increase by 10 times compared to those of the Zn@ZnS_WT_55 cell. Moreover, the Zn@ZnS_ST_55 cell always displays the minimum polarization voltage during cycling (Fig. S3f–j), revealing a (111) texture-induced reduction in the energy barrier of Zn2+ nucleation/dissolution. These results collectively elucidate the ZnS (111) texture-dictated ECS performance, i.e., ECS increases monotonically with enhancing (111) texture.

ZnS(111) orientation integrating electrochemical kinetics and mechanical strength
Electrochemical kinetics and mechanical strength are fundamental factors governing the functional efficacy and stability of ASEI9,33. Here, the effects of ZnS (111) texture intensity on these properties were examined to probe the mechanisms underlying the monotonic ECS-(111) texture relationship. The charge-transfer resistance Rct and reaction activation energy Era are derived from electrochemical impedance spectroscopy tests (Fig. 2d, e). Evidently, Zn@ZnS_x_55 electrodes exhibit much lower electrochemical resistance than that of bare Zn. Intriguingly, Rct and Era decreased dramatically with enhancing ZnS (111) texture and reach a minimum in the Zn@ZnS_ST_55 electrode, indicating higher Zn2+ transport kinetics intrinsic to the ZnS (111) orientation34. The Zn2+ conductivity of the ZnS_ST_55 ASEI is as high as 1.65×10−4 S·m−1, approximately 1.6 times greater than that of the ZnS_WT_55 ASEI (Fig. 2f). These results confirm that the in-plane ZnS (111) orientation facilitates Zn2+ migration and nucleation, imparting higher electrochemical kinetics than other orientations.

A significant increase in the hardness of ZnS_x_55 ASEIs with enhancing (111) texture is revealed by nanoindentation tests (Fig. 2g). This implies that the (111) orientation contributes to improving the yield and mechanical failure threshold of the ASEI. The ZnS_ST_55 ASEI also exhibits the highest positive strain rate sensitivity, indicating that it can more effectively withstand the high internal stress induced by rapid dendrite growth35. During long-term cycling services, the ASEI layer undergoes sustained stress from the interfacial deposition layer (Fig. S4h), thereby experiencing creep-related damage processes36,37. Indentation creep responses with controlled maximum loads and loading rates can simulate the service behavior of ASEIs under different charging states and current density scenarios. As shown in Fig. 2h, i, under any maximum load or loading rate condition, a stronger ZnS (111) texture consistently reduces the creep displacement, with ZnS_ST_55 ASEI displaying the smallest displacement. This trend proves that the (111) orientation of ZnS ASEI has higher creep resistance. Such ZnS (111) texture-imparted high mechanical strength and creep resistance can be attributed primarily to the high elastic modulus and low Schmid factor of the (111) crystal facet (Fig. 2j–l), which improve the elastic limit and reduce the resolved shear stress for defect multiplication, respectively.

Clearly, ZnS (111) orientation integrates high electrochemical kinetics and mechanical strength. A comparison of dendrite growth under varying charging areal capacities is presented in Figs. 3, S3k. In contrast to the thriving dendrites in the bare Zn anode, ZnS ASEIs exhibit different degrees of dendrite suppression. Specifically, (111) texture enhancement derives a transition of the dendrite morphology and ASEI damage mode: from densely coupled dendritic clusters and interconnected cracks in the ZnS_WT_55 ASEI, to stunted dendrites at the localized delamination site, and ultimately achieving high structural integrity with negligible dendrites and damage in the ZnS_ST_55 ASEI (Fig. 3a). Figure 3b–e show the surficial altitude fluctuations of electrodes developed at different charging areal capacities, providing quantitative insight into dendrite growth. The ZnS_ST_55 ASEI displays significantly reduced altitude fluctuations, with average dendrite widths (Fig. 3d) and fluctuation amplitudes (Fig. 3e), such as at 4 mAh cm−2, which are ~25.0% of those observed in ZnS_WT_55 ASEI. These results verify that a strong ZnS (111) texture boosts the dendrite-suppression efficacy of the ASEI, reinforcing its structural integrity and functional stability in service, which is responsible for the (111) texture intensity-dictated ECS performance (Figs. 2a–c, S3). Undoubtedly, the improved charge transport kinetics and mechanical damage threshold intrinsic to the (111) orientation constitute the primary electro-chemo-mechanical mechanisms (Fig. 2d–l)33. Herein, a key characteristic of the optimal crystallographic microstructure state—predominant in-plane (111) orientation—of ZnS ASEI can be identified.

The optimal grain boundary density
Building upon the preferential ZnS (111) orientation, the grain boundary density ρGB, another fundamental microstructure characteristic with an as-yet-uncovered regulation principle, is investigated to further refine the optimal crystallographic microstructure state of ASEI. A set of ZnS_ST_ρGB ASEIs with varying ρGB, ranging from 35 μm/μm2 to 100 μm/μm2, is synthesized. This ρGB regime corresponds to a grain size interval of ~95 nm to ~30 nm, which is typical for the microstructure of ASEIs constructed via slurry casting or in situ synthesis methodologies38,39. As compared in Fig. S5, the layer thickness, microstructure compactness, elemental distribution, and strong (111) texture of the ASEIs remain largely consistent, with ρGB emerging as the sole variable.

It is found that the hardness of ZnS_ST_ρGB ASEIs decreases with improving ρGB (Fig. 4a), following the inverse Hall-Petch relationship. Since the consistent grain orientation distribution ((111) texture) leads to an identical elastic modulus across the sample set (Fig. S6a), the observed negative correlation between hardness and ρGB likely arises from GB-mediated deformation mechanisms, such as GB sliding or rotation, activated as dislocations are suppressed by the nanoscale grain size40. One can also find that the mechanical strength is more sensitive to ρGB than to the (111) texture intensity (Figs. 4a, 2g). The prevalence of GB-mediated plasticity usually renders the material susceptible to creep41. The ZnS ASEI is no exception; the larger the ρGB, the lower the creep resistance (Fig. 4b, c), regardless of the maximum load and loading rate.

As shown in Fig. 4d–f, improving ρGB monotonously lowers Rct and Era while boosting Zn2+ conductivity. Meanwhile, the cyclic voltammetry curves of ZnS ASEIs with higher ρGB exhibit larger enclosed areas, higher peak current densities, and lower onset overpotentials, suggesting enhanced Zn plating/stripping kinetics (Fig. 4g). Hybrid Monte Carlo and molecular dynamics simulations reveal that Zn2+ migration in ASEI occurs mainly along the GB, with the migration rate almost proportional to ρGB (Fig. S7b). These observations confirm a positive correlation between electrochemical kinetics and ρGB, along with the underlying mechanism—GB-mediated ionic transport.

The opposing trends in the dependence of electrochemical kinetics and mechanical strength on ρGB complicate the identification of the optimal ρGB for ECS performance. Galvanostatic Zn plating/stripping cycling tests of symmetric cells indeed unveil a non-monotonic dependence of the cycling life on ρGB, with the lifespan initially increasing as ρGB improves, before subsequently decreasing (Figs. 4h, S8a, b). Intriguingly, there exists a critical grain boundary density, ρGB,c ~55 μm/μm2, for the longest lifespans at any current densities. For instance, the cycling time of Zn@ZnS_ST_55-based symmetric cells exceeds 1000 h at 2 mA cm−2 and even over 2000 h at a relatively high current density of 10 mA cm−2. This ρGB,c was further confirmed through CE tests (Figs. 4i, j, S8c–j). The corresponding Zn@ZnS_ST_55||Ti cell always exhibits the highest Coulombic efficiency with minimal efficiency fluctuation, the maximum number of charging/discharging cycles, and the lowest polarization voltage. As an exemplar, at 5 mA cm−2, the ZnS_ST_55 displays over 3400 charging/discharging cycles—double that of ZnS_ST_35 and ZnS_ST_100, alongside a high average CE of 99.92%. Clearly, ρGB,c ~55 μm/μm2 is exactly the optimal ρGB for ECS performance, not by meeting the individual requirements of either electrochemical kinetics or mechanical strength but by balancing the two.

The optimal ρGB balancing electrochemical kinetics and mechanical strength
The mutually exclusive dependencies of the electrochemical kinetics and mechanical strength on ρGB suggest that ρGB,c is delineated by the trade-off between the ECS contribution factors. To unveil the underlying mechanisms, the evolution of ASEI damage is investigated (Fig. 5a). For the lowest ρGB case (the first subgraph in Fig. 5a), large discretely distributed bump-like Zn protrusions are observed, whereas the residual regions remain damage-free. This implies a highly non-uniform Zn deposition process. Such protrusions will serve as the preferential Zn deposition sites, which exacerbate uncontrollable dendrite growth33. As ρGB increases (the second subgraph in Fig. 5a), huge dendrite protrusions are partially suppressed, supplanted by short crack interaction-induced local delamination and local diffuse dendrite growth. Upon reaching ρGB,c (the third subgraph in Fig. 5a), only a few discrete cracks appear, with no exposed dendrites, indicating effectively suppressed dendrite growth, which is responsible for the improved ECS performance (Figs. 4h–j, S8). The appearance of such an near-ideal morphology signifies two service characteristics of the ASEI enabled by ρGB,c: (i) a homogeneous Zn deposition process to alleviate stress concentration, and (ii) improved yield and damage thresholds to preserve structural integrity and thus functional stability. When ρGB exceeds the ρGB,c (the fourth subgraph in Fig. 5a), however, delamination-induced diffused dendrites destroy the structural integrity of ASEI, with the remaining islands being eroded by dendrites as well, significantly reducing the lifespan and CE (Figs. 4h–j, S8). The altitude contours of ASEIs after varying capacity services are compared in Figs. 5b, S8k, l. The ZnS_ST_55 ASEI exhibits the lowest altitude fluctuation at any charging capacity. In contrast, as ρGB deviates from the ρGB,c, significant fluctuations appear with the development of dendrite peaks. Driven by an inhomogeneous electric field and ionic distribution, dendritic tips are preferred by Zn deposition, which feeds back to promote dendrite growth42. Such a self-catalytic cycle intensifies uncontrollable dendrite growth, accelerating structural damage and thus functional degradation of the anode.

As simulated by molecular dynamics, Zn2+ transport and early-stage deposition are ASEI GB-dependent processes (Figs. 5f, S7). Low ρGB renders limited Zn nucleation sites but a faster growth rate for each nucleus. The growing Zn dendrites have a direct piercing effect on ASEI, and the strength mismatch between them could introduce extra shear interactions (Fig. S4h). These effects collectively yield sparsely distributed yet intense stress concentrations along GBs (Fig. 5c). Although the low-ρGB ASEI exhibit high strength (Fig. 4a–c), discrete long cracks form once local yielding occurs, leading to the development of bump-like dendrite protrusions. Moreover, the broader grain size distribution of the ZnS_ST_35 ASEI is also a potential factor promoting dendrite protrusion formation since it exacerbates nucleation heterogeneity (Fig. S5b). Improving ρGB can increase the uniformity of Zn deposition by providing more transport channels and nucleation sites43. However, excessively high ρGB reduces the mechanical strength, which enables extensive nucleation of short cracks, eventually leading to widespread crack erosion and diffuse dendrites (Fig. 5e). In particular, upon approximating ρGB,c ~55 μm/μm2, there are sufficient GBs for ionic transport and Zn nucleation, and relatively high mechanical damage thresholds are maintained. This represents the optimal trade-off between electrochemical kinetics and mechanical strength, providing a unique opportunity to resist both bump-like protrusions and diffused dendrite formations (Fig. 5d), thereby enabling ZnS_ST_55 ASEI to maintain good structural integrity. Another key point worth noting is that the ZnS ASEIs exhibit robust grain structure stability, chemical stability and insolubility during service, with no detectable grain coarsening, phase transformation, or side reactions with the electrolyte (Fig. S2c, d, S9). This makes cracking followed by fragmentation the primary mechanism of ASEI consumption. Minimal mechanical damage endows ZnS_ST_55 ASEI with the lowest consumption rate, thereby enhancing its functional robustness. Thus, herein, another key characteristic of the optimal crystallographic microstructure state of ZnS ASEI—ρGB,c ~55 μm/μm2—is identified.

Crystallographic microstructure engineering for ASEI
The existence and the high ECS-improving efficacy of the optimal ZnS ASEI microstructure state, i.e., predominant in-plane (111) orientation coupled with a critical ρGB,c ~55 μm/μm2, suggest an efficient ASEI design route—crystallographic microstructure engineering. This route advocates regulating the microstructural characteristics according to their impacts on the electrochemical kinetics and mechanical strength, and then strategically integrate them. If the impacts of a microstructural characteristic on the electrochemical and mechanical properties are synergistic, as exemplified by that of the ZnS ASEI (111) orientation or texture (the lower part in Fig. 6a), it should be monotonically enhanced. Should the impacts exhibit a trade-off relationship, it is necessary to identify the critical threshold of microstructural characteristic that optimally balances mechanical strength and kinetic performance, as exemplified by the regulation of the ρGB of ZnS ASEI (the upper part in Fig. 6a). Strategically incorporating the optimizations of multiple microstructural characteristics into an ASEI can simultaneously improve ionic transport rate, nucleation homogeneity, and mechanical damage threshold, which helps retain structural integrity and functional stability, thereby peaking the ECS performance (Fig. 6). Note that identifying the optimal ASEI microstructure state should follow the principle—prioritizing characteristics dictated by the material chemical composition, then those dependent on these identified ones (Fig. S10). In the ZnS case, the (111) orientation is intrinsically dictated by its chemical composition and sphalerite-phase lattice, thus necessitating to be identified with priority. While the effect of regulating ρGB may depend on the prevailing crystal orientation and should therefore be determined subsequently. Failure to follow this sequence may yield a pseudo-optimal microstructural state.

For the ZnS ASEIs developed in this study, crystallographic microstructure engineering is successfully implemented in ZnS_ST_55 ASEI, imparting 1.5~10-fold extensions in the lifespans of symmetric cells as compared with those of ZnS ASEIs with no or only partially optimized microstructures (Figs. 2a, 4h). Moreover, there is even an 18-fold lifespan extension relative to bare Zn. The electrode protected by ZnS_ST_55 ASEI demonstrates favorable plating/stripping reversibility across a broad current density range—over 3400 cycles with a 99.92% CE at 5 mA cm−2 and 2600 cycles with a 99.82% CE at even 10 mA cm−2. Such performance enhancement rivals or even exceeds that achieved by chemical composition-dependent ASEI design, electrolyte engineering, ASEI orientation optimization and zinc-host regulation (Fig. 6b). This comparison demonstrates the appreciable efficacy of ASEI crystallographic microstructure engineering in improving ECS performance.

Note that crystallographic microstructure engineering also holds significant potential for application to ASEIs with diverse chemistries across various metal negative electrode systems. This can be supported by the documented experimental cases and/or theoretical analyses in which variations in ASEI microstructure always dramatically affect electrode cycling stability, as summarized in Table S2. Specifically, three fundamentals are shared among these cases. First, a significant extension in electrode lifespan is always achieved at a specific ASEI microstructure state17,21. Second, the underlying mechanisms often involve, directly or indirectly, the principle of ASEI crystallographic microstructure engineering—integrating and balancing electrochemical kinetics and mechanical strength44. Third, although most efforts have focused on regulating individual crystallographic microstructural features, cases meeting the first two fundamentals encompass ASEIs with diverse chemistries and applied in various electrode systems, including sulfides, oxides, nitrides, fluorides, or metal-organic complexes, used in Zn, Li, Na, and Mg electrodes (Table S2). These suggest that advancing crystallographic microstructure engineering in more ASEIs—enabling synergistic optimization of key microstructural characteristics through scalable, low-cost processes—holds promise for enhancing the performance of next-generation metal batteries.

Methods
ASEI fabrication, microstructural and physiochemical characterizations
All chemicals were used directly without any purification treatment. Zinc sulfate heptahydrate (ZnSO4·7H2O, >99.99%) was purchased from Aladdin Chemistry Co., Ltd. High-purity zinc sulfide (ZnS, 99.99%) target was supplied by Hefei Kejing Materials Technology Co., Ltd. Commercial cold-rolling zinc and titanium foils (99.99%, 100 μm thickness), Glass fiber separator (Whatman GF/D, 675 μm thickness) were supplied by Shenzhen Kejing Star Technology Co., Ltd. Deionized water (18.2 MΩ cm at 23.5 °C) was generated by DURA Pro 12/24.

Pulsed laser deposition system with a 248 nm wavelength KrF excimer laser was utilized for epitaxial deposition of ZnS layers on a Zn electrode. Before deposition, Zn foil was washed with acetone, deionized water, and ethanol thoroughly. Deposition chamber was evacuated to ~4×10−8 torr for avoiding oxygen pollution. The target-substrate distance was fixed at 5.0 cm, and the laser energy was set as 400 mJ with a 2 Hz pulse frequency. The texture intensity and ρGB of ZnS ASEI were controlled by the modulation of Ar partial pressure (from 2×10−3 to 1×10−1 torr), growth temperature (150~250 °C), and deposition time (0.5~4.0 h). The as-prepared electrode was washed, followed by drying and storing under a nitrogen atmosphere.

The morphology of the ZnS ASEI were observed by scanning electron microscopy (SEM, ZEISS Gemini SEM 500). A cross-section polisher (IB-19520 JEOL) was carried out to cut the Zn@ZnS_x_ρGB electrode for an accurate measurement of ASEI thickness. The microstructure and chemical components were characterized by a high-resolution transmission electron microscope (HRTEM, FEI Talos F200X G2) equipped with an energy-dispersive X-ray spectroscopy detector under 200 kV. The distribution and mean value of grain size for each ASEI were determined by manually measuring the dimensions of over 350 spatially consecutive grains. The average grain size was validated against that determined by the standard Heyn linear intercept method (ASTM E112-13) to ensure accuracy. Grazing incidence X-ray diffraction (XRD, Rigaku Smartlab 9KW) was performed at 6° min-1 (step size: 0.01°) from 5° to 90° with a copper radiation (Cu Kα=1.5418 Å). The pole figures of ZnS coating were characterized on an X-ray diffractometer (Panalytical X’pert mrd), with the scanning azimuthal range from 0° to 360° at each tilt angle (0° to 75°). X-ray photoelectron spectroscopy (XPS) with an Al Kα source (Thermo Scientific K-Alpha) under 12 kV with a 400 μm spot size was performed to examine the chemical state of bare Zn (polished under Ar-ion sputtering at 2 kV) and ZnS ASEIs. Confocal laser scanning microscopy (CLSM, Leica DCM8) was employed to measure the altitude fluctuation of Zn dendrites. To characterize the ASEIs during cycling, the cycled cells were disassembled at 25±0.1 °C and the Zn@ZnS_x_ρGB electrodes were washed to remove the residual electrolyte, followed by drying and storing in glass containers filled with nitrogen atmosphere until transfer for SEM, XRD, XPS, and CLSM analysis.

Electrochemical and mechanical measurements
2 M ZnSO4 dissolved in deionized water was used as electrolyte. Symmetric and asymmetric cells were assembled in coin-type cells (CR-2032) with 150 μL electrolyte. All electrodes employed in the coin-type cells were punched into circular disks with a diameter of 12 mm. The glass fiber separators were prepared as 16 mm diameter circles. Potentiostatic electrochemical impedance spectroscopy (EIS) of symmetric cells was performed over a frequency range of 0.01 Hz to 100 kHz using a voltage amplitude of 10 mV under open-circuit voltage conditions. The reaction activation energy was derived from the Arrhenius equation 1/Rct = A·exp(−Era/RT), where Rct represents the charge-transfer resistance and A, R, and T represent the frequency, gas constant, and temperature, respectively. Cyclic voltammetry was performed with a scan rate of 1 mV s−1 from −0.2 to 1.0 V. Ionic conductivity was tested via a blocking electrode method45. For this test, the ZnS ASEI was deposited onto the Ti foil, followed with EIS measurements were performed with a frequency from 0.1 Hz to 100 kHz. The ionic conductivity was then calculated as σ=L/(Rb·S), where Rb represents the resistance, L denotes the thickness of the ZnS ASEI, and S indicates the contact area. All tests were carried out on an electrochemical station (Reference 3000, Gamry Instruments).

All cycling tests were performed in a climatic/environmental chamber at 25±0.1 °C with Land battery testing systems (CT3002A). Galvanostatic charge/discharge tests of the symmetric cells were performed at 2 mA cm−2 to 2 mAh cm−2, 5 mA cm−2 to 5 mAh cm−2, and 10 mA cm−2 to 1 mAh cm−2. Coulombic efficiency (CE) tests were carried out at varying current conditions (2, 5, 8, and 10 mA cm−2) with a cut-off potential of 0.6 V (vs. Zn2+/Zn) on the asymmetric cells to evaluate the stability and reversibility of the ZnS ASEI. The CE was calculated as follows:

CE = (discharge capacity / charge capacity) × 100% (1)

Nanoindentation tests were performed alternatively under continuous stiffness and quasi-static creep modes, using a Berkovich indenter. To mitigate the interference of zinc substrate surface roughness, Zn foils were electrochemically polished to achieve a mirror-like surface before deposition. To avoid substrate effects, indentation depth remains less than 10% of the coating thickness46. The elastic modulus and hardness were calculated based on the Hay-Crawford model47 and Saha-Nix model48, respectively. The holding time of creep measurements was consistently set to be 60 s.

DFT calculation and MD simulation
The Vienna ab initial simulation package (VASP, version 5.4.4) was adopted for DFT calculations via the projector-augmented wave (PAW) method49,50. The generalized gradient approximation (GGA) based on the Perdew-Burke-Ernzerhof (PBE) formulation was chosen to describe the exchange-correlation interaction51. The optimized ZnS bulk model with the space group of F-43m and Zn of P63/mmm was adopted for constructing the surface model. Six-layer slabs were cleaved with a vacuum region of 15 Å. An energy cutoff of 450 eV was applied. It was verified that a larger energy cutoff could not produce a more accurate prediction for our calculations. The Monkhorst-Pack scheme k-points grid of 3×3×1 was set for Brillouin zone sampling. The electronic self-consistent field (SCF) convergence criterion was set to 10−6 eV. The criterion for ionic relaxation was set as 10−5 eV for energy convergence, and 0.03 eV Å−1 for residual force convergence. The adsorption energy (Ea) was calculated as:

Ea = EZn-substrate − EZn − Esubstrate (2)

where EZn-substrate, EZn, and Esubstrate represent the energy of Zn adsorbed on the substrate, the energy of a single Zn atom, and the energy of the clean substrate, respectively. The optimized computational models were supplied in Supplementary Data 1. The charge density difference distribution was calculated as:

∇ρ = ρZn-substrate − ρZn − ρsubstrate (3)

where ρZn-substrate, ρZn, and ρsubstrate represent the total charge density of the adsorption structure, the charge density of a single Zn atom, and the charge density of the substrate17,34,52. The VESTA software was utilized for the visualization of adsorption structure and charge density distribution53.

Molecular dynamics (MD) simulations were performed on nanocrystalline ZnS with varying ρGB using the LAMMPS package54. The Stillinger-Weber interatomic potential was adopted55. Visualization and post-processing of atomic configurations were carried out using Ovito software56. The ZnS models were constructed via the Voronoi tessellation method, implemented within the Atomsk software57. The equal numbers of zinc atoms were controlled to randomly distribute on the ZnS substrate. A hybrid Monte Carlo/molecular dynamics optimization was employed to explore energetically favorable adsorption sites and migration pathways for the zinc atom through ZnS. The atomic entropy fingerprint method, a proven approach for effective GB identification58, was adopted to distinguish the grain boundary of ZnS and the zinc-atom migration track. The relevant atomic configurations were supplied in Supplementary Data 2. Checking Supplementary Information for more details on modeling information.

Peer review rounds
[{"round": 1, "reviewer_comments": {"reviewer_1": "The authors present a study into suppressing dendrite formation on the zinc metal anode in the context of rechargeable aqueous zinc batteries. The idea centers on using an interfacial layer of ZnS to control the anode’s surface microstructure. They study the relationship of its grain structure to the overall cycling performance of the anode, finding optimal conditions that trade-off between its mechanical and ionic conductivity properties.\nThe study is interesting and has good analysis. I think it has some decent significance to the field of rechargeable aqueous zinc batteries, although their results cannot directly translate to other rechargeable battery metal anodes without being backed up with significant extra experimental studies (well-beyond the scope of a single paper). Whether this meets the novelty/impact criteria for Nature Comms will be up to the editors based on this assessment.\nSome more specific comments:\nThe title needs to mention the context of aqueous zinc rechargeable batteries. While I appreciate the authors would like to suggest the idea of structural crystallography of the anode interface has broad relevance across all metal anodes, these findings can’t really be taken as universal to all metal anodes on the basis of just the results in this manuscript. It lacks any further studies of other chemistries, or even other artificial interface materials, and the level of studies needed would be more than a doubling of the amount of work already in this submission.\nHow does the grain structure evolve over repeated cycles? If it doesn't change, why not? If it does, does this have any ramifications for long-term use?\nIs there any ZnS dissolution?\nWhy was ZnS selected as the artificial interface layer?\nI appreciate it’s difficult to write in a non-native language! But the writing is not good. A thesaurus has been overused (misused) throughout, and has made it difficult to follow as a result. Sometimes due to poor grammar, or convoluted phrasing, or just incorrect use of a word. Again, I appreciate the authors are likely non-native speakers, but the authors can make it easier for themselves by not feeling the need to use overtly ostentatious language. The paper needs an extensive rewrite to make it readable. Some (of many possible) examples: “... which may render multiple competitive and/or synergistic electro-chemomechanical mechanisms, complexing the regulation principles.” Some of this sentence is fine, but this last bit is not correct. “Certainly, if the impacts are competitive, it is demanded to delineate the threshold of microstructure characteristic that can effectively reconcile the kinetics strength trade-off” is faintly comical in how contrived it is to seem sophisticated. Also, the word \"doesn't\" appears as an informal contraction in the manuscript.\nOn page 14, the authors claim “crystallographic microstructure engineering does not involve chemical addition and can be realized in situ during ASEI synthesizing, making this route intrinsically cost-effective and highly practicable.” This is directly contradicted by their own work, where they have to use a pulsed laser deposition technique in order to control the texturing adequately. The authors can’t have it both ways: it is either essential to control the ASEI crystal structure, in which case it will be necessary to use sophisticated thin-film deposition techniques, or making an artificial surface interface is simple, in which case it can be done via a simple in situ electrochemical deposition. Without experimental evidence, I cannot see how they can make their current claim here regarding practicality, and certainly not how it is more practical than simple electrolyte engineering. I think it is fine to broadly argue the merits of artificial anode creation versus electrolyte engineering (which isn’t a particularly new set of insights), but this work doesn’t really address one of the main limits with artificial SEIs, which was not their quality but rather their ease of scalable implementation. PLD isn't exactly industrially practical compared to electrolyte additives. To be honest, I think the whole discussion around figure 6 b is misleading and largely unnecessary, and should just be removed.", "reviewer_2": "This manuscript presents a thorough investigation into crystallographic microstructure engineering of artificial solid-electrolyte interphases (ASEIs) to improve the stability of metal anodes. Using ZnS-based ASEIs in aqueous Zn metal batteries as a representative system, the authors tackle the challenge of dendrite suppression by systematically elucidating the relationships among grain orientation, grain boundary density (ρGB), and the resulting electrochemical and mechanical properties of ASEIs. The identification of an optimal microstructure—characterized by a predominant (111) orientation and a critical ρGB,c < 55 μm/μm²—demonstrates significant cycling performance (3400 cycles, 99.92% Coulombic efficiency), marking a notable advancement. The study convincingly argues that crystallographic optimization can outperform traditional compositional modifications, offering a potentially universal ASEI design strategy. This work is of interest and could be considered for publication in Nature Communications after the following critical issues are addressed.\n1. The ZnS layer fabricated via pulsed laser deposition (PLD) exhibits a thickness of approximately 1.5 μm. This value substantially exceeds the conventional thickness range of SEIs, which are typically on the order of several to tens of nanometers. Thus, referring to this layer as an “ASEI” may be conceptually misleading. It would be more appropriate to describe it as a modification layer or an interfacial coating.\n2. While the ZnS layer with (111) orientation demonstrates superior mechanical robustness, the underlying Zn metal anode is relatively soft and mechanically weaker. The mechanical mismatch at the ZnS/Zn interface could result in uneven stress distribution during cycling, potentially introducing localized stress concentrations (e.g., shear and tensile stresses). These may act as mechanical failure initiation sites on the Zn anode and should be thoroughly evaluated.\n3. The manuscript lacks discussion on the chemical stability of the ZnS layer under repetitive Zn plating/stripping. It remains unclear whether the ZnS layer undergoes chemical reactions with the electrolyte or evolves during extended cycling. Addressing this question is crucial for validating the long-term reliability of the engineered interface.\n4. To convincingly demonstrate the practical effectiveness of ZnS coatings in suppressing dendritic growth, symmetric Zn//Zn cell testing should be conducted under higher areal capacity conditions. This would better mimic realistic usage scenarios and further validate the claimed performance improvements.\n5. A minor issue: Table S1 should include additional critical parameters influencing electrochemical performance, such as electrolyte composition and volume, areal capacity, and depth of discharge. These are essential for enabling proper comparison and reproducibility.", "reviewer_3": "This manuscript presents an impressive story in the exploration of new aSEI design route. Taking the ZnS aSEI served in aqueous zinc batteries as a paradigm, the optimal microstructure state—predominant in-plane (111) orientation coupled with a critical grain boundary density ρGB,c was identified by systematical microstructure modulation. This optimization outperforms most reported chemical composition-dependent aSEI designs, delivering unprecedented effectiveness in dendrite suppression, anode lifespan extension and plating/stripping cycling stabilization. It indicates the emergence of a transformative solution to the long-standing bottleneck of efficacy limitation and cross-strategy incompatibility in conventional aSEI designs. Indeed, having elucidated the mechanisms of how microstructural characteristics affect electrochemical kinetics and mechanical strength, a new aSEI design route—crystallographic microstructure engineering—was proposed and rationalized. These findings constitute a respectable progress, with notable innovations in aSEI design concept and anode performance improvement, in the field of rechargeable metal batteries. It can meet the standards of Nature Communications, and is likely to engage both academic and industrial audience in energy science community. I would like to support its publication.\nThe majority of claims in the manuscript have been well rationalized. But there is still a critical issue which may deserve the authors’ attention. The implementation of crystallographic microstructure engineering in aSEI inevitably involves synergistic optimization of multiple microstructure characteristics. Thus, key questions remain: How does the modulation sequence of different microstructural characteristics affect the outcomes, and what principles on the modulation sequence should be followed to achieve the ‘truly’ optimal microstructure state? Since the optimal state of a microstructure characteristic should be interdependent with others, the coordinated optimization of multiple characteristics therefore must be affected by their modulation sequence. It may attain a fake or artifactual optimal state if the modulation sequence is improper. Just taking the ZnS aSEI as an example: if one first identifies the optimal grain boundary density ρc under a non-(111) orientation, then fixes ρc while searching for the optimal orientation, would the resulting ‘optimal’ microstructure state and anode performances differ from those determined in current work? In this regard, to ensure the reliability and practicality of crystallographic microstructure engineering in aSEIs, it is critical to elucidate the principles of the modulation sequence and interdependencies of multiple microstructure characteristics.\nMinor additional suggestions:\n(1)Line 189-191: The statement “…the high elastic modulus and low Schmid factor…improve the elastic limit and the resolved shear stress for defect multiplication” is really confusion. Low Schmid factor renders low resolved shear stress on slip plane, thus requiring higher applied stress for defects activity.\n(2)Line 70: Non-standard reference formatting.\n(3)Line 92: What does “CE” means?\n(4)Line 93: Should is be stated as \"most chemical composition optimized\" or \"chemical composition optimized\"?\n(5)It is suggested to delete the less-used abbreviations, such as “PLD”, to enhance the readability.", "reviewer_4": "This work proposes that the crystallographic structural design of an artificial solid–electrolyte interphase (ASEI) can modulate Zn anode behavior, ultimately achieving enhanced cycling stability. The findings may provide some useful insights into interfacial engineering strategies for Zn-based batteries, which could be published in Nature Communications.\nHowever, several important issues should be addressed as follows:\n1) The study demonstrates performance improvement of Zn anodes using a crystallographically tailored ZnS_ST(111)_55 ASEI. However, given the broader claim of ASEI design, the authors should discuss the applicability of this approach to other metallic anodes. Can the same crystallographic design strategy be extended to systems beyond Zn—e.g., Li, Na, or Mg? Some discussion or hypothetical extension would strengthen the conceptual universality.\n2) Although the manuscript emphasizes crystallographic microstructural rather than chemical composition-dependent control, it remains unclear whether this crystallographic modulation is effective only for ZnS, or potentially applicable to other compounds. The authors should comment on whether similar performance could be realized using other sulfides or even non-sulfide materials.\n3) The ASEI layer in this work is controlled to be ~1.5 μm. Is there a critical thickness threshold? Please discuss how ASEI thickness affects the performance overall.\n4) The grain size distributions in Figs. S2 and S5 are central to the argument regarding grain boundary (GB) effects. However, the method used to extract these distributions is not clearly described. Since GBs are central to the discussion, direct and spatially resolved techniques such as EBSD would provide more conclusive insights. Please clarify the current method and consider incorporating more direct microstructural evidence.\n5) It is unexpected that a modest increase in ρGB from 35 to 40 leads to doubled cycle life and other performance gains. Meanwhile, Fig. S5b shows that ZnS_ST_35 has a much broader grain size distribution compared to other samples. Since similar ρGB values can achieved with different grain size profiles, please discuss whether the performance improvement is solely attributable to ρGB, or if the size distribution also plays a critical role.\n6) How does the ASEI layer evolve during cycling? Are there structural changes (e.g., roughening, cracking, dissolution)? If operando or ex-situ monitoring has been performed (e.g., operando cross-sectional imaging, post-cycling cross-sectional SEM), please present them to support the working mechanism of ASEI clarified in this study.\n7) In Fig. 5d, the MC/MD simulations suggest Zn preferentially deposits along GBs in low-ρGB ASEI, while flat Zn deposition occurs underneath the ZnS ASEI in high-ρGB cases. However, these trends seem to differ from some experimental observations. Please clarify the connection and discrepancies herein.\n8) In the DFT calculation of adsorption energy, was the charge of adsorbed Zn atom considered? Or simply a neutral Zn atom?", "reviewer_5": "I co-reviewed this manuscript with one of the reviewers who provided the listed reports. This is part of the Nature Communications initiative to facilitate training in peer review and to provide appropriate recognition for Early Career Researchers who co-review manuscripts."}, "author_response": "Responses to Reviewers\nReviewer #1:\nComments: The authors present a study into suppressing dendrite formation on the zinc metal\nanode in the context of rechargeable aqueous zinc batteries. The idea centers on using an\ninterfacial layer of ZnS to control the anode’s surface microstructure. They study the relationship\nof its grain structure to the overall cycling performance of the anode, finding optimal conditions that\ntrade-off between its mechanical and ionic conductivity properties.\nThe study is interesting and has good analysis. I think it has some decent significance to the field\nof rechargeable aqueous zinc batteries, although their results cannot directly translate to other\nrechargeable battery metal anodes without being backed up with significant extra experimental\nstudies (well-beyond the scope of a single paper). Whether this meets the novelty/impact criteria\nfor Nature Comms will be up to the editors based on this assessment.\nResponse: Thank you for the kind comments and suggestions sincerely. The concerns are definitely\nsolid and helpful, which have been seriously considered. Revisions were made accordingly, as\nhighlighted using red font in the Revised Manuscript or Revised Supplementary Information.\nComment 1.1: The title needs to mention the context of aqueous zinc rechargeable batteries.\nWhile I appreciate the authors would like to suggest the idea of structural crystallography of the\nanode interface has broad relevance across all metal anodes, these findings can’t really be taken\nas universal to all metal anodes on the basis of just the results in this manuscript. It lacks any\nfurther studies of other chemistries, or even other artificial interface materials, and the level of\nstudies needed would be more than a doubling of the amount of work already in this submission.\nResponse 1.1: Thanks for the constructive suggestion. To accurately encapsulate the main findings and\nenhance reader comprehension, the title has been revised as \"Crystallographic Microstructure\nEngineering for Artificial Solid Electrolyte Interphases toward Ultra-Stable Zinc Anode\". While, an\nalternative title, \"Crystallographic Microstructure Engineering for Artificial Solid Electrolyte\nInterphases toward Ultra-Stable Metallic Anode: a paradigm in Aqueous Zn Battery Application\", is\nalso considered but temporarily set aside due to its excessive verbosity. We would be happy to hear\nfrom you if there are any more considerations on the title.\nIndeed, the previous manuscript is limited by the lack of extended verification and discussion on\nthe broad applicability and transferability of the proposed ASEI design route, crystallographic\nmicrostructure engineering, to other metallic anodes. The reviewer's feedback brings this to our\nattention. Thank you sincerely for this.\n1 / 34\nActually, synergistic regulation of multiple crystallographic microstructural features within a\nsingle ASEI, to the authors' knowledge, remained unexplored prior to this work, while several studies\nhad reported the optimization of individual microstructural property in specific ASEIs. This insight\noffers a potential shortcut for validating the broad applicability of ASEI crystallographic microstructure\nengineering, which entails regulating the typical microstructural characteristics to the optimal states\nbased on the principle of integrating and/or balancing electrochemical kinetics and mechanical strength.\nSpecifically, if there are enough cases in which targeted modulation of individual crystallographic\nmicrostructural feature in a specific ASEI—involving the principle of synergizing or balancing\nmechanical strength and electrochemical kinetics—can effectively improve anode performance, the\nbroad applicability of this design route can be thereby confirmed. In this logic framework, three\nfundamentals must be met by the cases. (i) The principle of integrating or balancing mechanical strength\nand electrochemical kinetics should be followed or be the underlying mechanism in ASEI's\nmicrostructure modulation. (ii) Significant improvement in anode cycling stability is rendered by the\nmodulation. (iii) The cases meeting the first two fundamentals must encompass diverse metallic anode\nsystems such as the ASEIs in Zn, Li, Na, and Mg anodes. Simultaneously engineering multiple\ncrystallographic microstructural features within a single ASEI, although highly desirable, is not\nmandatory.\nGuided by this logic, we systematically retrieved the experimental records and theoretical\ninvestigations related to the crystallographic microstructural regulation of ASEIs. The representative\ncases are collected in Table S2 (Revised Supplementary Information, Page S22). Surprisingly, a\nnumber of ASEI design cases, involving those served in Zn, Li, Na, and Mg metal anodes, indeed meet\nthe above fundamentals. For instance, Zhou et al. demonstrate that a highly (001)-orientated Li N ASEI\n3\nextends the cycling life of Li metal anode by ~1.25-fold compared to the randomly oriented counterpart,\ndue to the integration of high mechanical modulus and ionic conductivity1. A comparative analysis of\nNa₂S ASEIs with controlled grain sizes—as reported by Yu et al. and Yang et al.—reveals that a critical\nsize of ∼50 nm can markedly improve the cycling stability of Na anode, outperforming coarser\nmicrostructures2,3. Moreover, Fu et al. verifies that the Mg-MOF-74 ASEI with a strong (101) texture\nenables a dramatic improvement in the cycling lifespan of Mg anode, which is attributed to the\noptimized Mg2+ diffusion kinetics4. These paradigms collectively confirm the broad applicability of\ncrystallographic microstructure engineering across various metal anode systems.\nTo address these insights, an additional discussion has been incorporated in the Revised\nManuscript as follows (the last paragraph in Page 14) to validate the broad applicability and\ntransferability of crystallographic microstructure engineering.\nNote that crystallographic microstructure engineering also holds significant potential for\napplication to ASEIs with diverse chemistries across various metal anode systems. This can be\nsupported by the documented experimental cases and/or theoretical analyses in which variations in\nASEI microstructure always dramatically affect anode cycling stability, as summarized in Table S2.\nSpecifically, three fundamentals are shared among these cases. First, a significant extension in anode\n2 / 34\nlifespan is always achieved at a specific ASEI microstructure state17,21. Second, the underlying\nmechanisms often involve, directly or indirectly, the principle of ASEI crystallographic microstructure\nengineering—integrating and balancing electrochemical kinetics and mechanical strength44 Third,\nalthough most efforts have focused on regulating individual crystallographic microstructural features,\ncases meeting the first two fundamentals encompass ASEIs with diverse chemistries and applied in\nvarious anode systems, including sulfides, oxides, nitrides, fluorides, or metal-organic complexes, used\nin Zn, Li, Na, and Mg anodes (Table S2). These suggest that advancing crystallographic microstructure\nengineering in more ASEIs—enabling synergistic optimization of key microstructural characteristics\nthrough scalable, low-cost processes—holds promise for enhancing the performance of next-generation\nmetal batteries.\nComment 1.2: How does the grain structure evolve over repeated cycles? If it doesn't change,\nwhy not? If it does, does this have any ramifications for long-term use?\nResponse 1.2: The concerns are absolutely insightful. The stability of ASEI grain structure is essential\nto ensure low ASEI consumption rate and thus functional sustainability during service. Actually, the\nevolutions of grain structure—including the crystallographic microstructure and chemical composition,\nand the possible influence on ASEI's functionality have been considered and verified during the\ninvestigation. Specifically, high-resolution microstructural characterization, crystallographic analysis\n(via XRD), and chemical composition profiling (via XPS) were conducted at multiple cycling stages,\nas partially shown in Fig. S9 (Revised Supplementary Information, Page S16). The results\ndemonstrate that the current ASEIs, especially the ZnS_ST_55 sample, exhibit exceptional\nmicrostructural and chemical stabilities, which remain almost unchanged during cycling. There are two\nkey physics behind this. (i) The intrinsic mechanical stability of ZnS grains prevents\nmechanochemically driven coarsening or phase transformation, even upon cracking and fragmentation.\n(ii) The chemical inertness of ZnS suppresses the chemical reactions with electrolyte, thereby avoiding\nside reaction-induced dissolution and/or decomposition.\nIn the Revised Manuscript, a streamlined discussion has been added in the first paragraph of\nPage 13 as follows to address the grain structure stability.\n…Another key point worth to note is that the ZnS ASEIs exhibit exceptional grain structure\nstability, chemical stability and insolubility during service, with no detectable grain coarsening,\nphase transformation, or side reactions with the electrolyte (Figs. S2c-d & S9). This makes cracking\nfollowed by fragmentation the primary mechanism of ASEI consumption. Minimal mechanical damage thus\nendows ZnS_ST_55 ASEI with the lowest consumption rate, thereby enhancing its functional\nrobustness…\nPlease check Response 1.3 for the explanations of ASEI insolubility.\nIn the Revised Supplementary Information, an Extended Discussion entitled \"Grain structure\nstability and chemical stability of ZnS ASEIs during repeated Zn plating/stripping cycles\" (Page S3)\n3 / 34\nhas been added as below to detail the experimental results and underlying physic.\nThe ASEI's grain structure and chemical stability is another critical prerequisite to ensure the\nfunctional sustainability and thus the electrode cycling stability. Here, microstructure evolution of\nZnS_ST_ρ ASEIs over repeated Zn plating/stripping cycles is investigated (Fig. S9). In contrast to\nGB\nthe thriving dendrite developed in bare Zn (Figs. S9a1, b1 & c1), ZnS ASEIs exhibit different degrees\nof dendrite suppression. Owing to sluggish electrochemical kinetics, the lowest-ρ ASEI develops\nGB\nultra-large Zn protrusions (Figs. S9a2 & b2), with the original microstructure retaining in the\nsurrounding regions (Fig. S9c2), suggesting highly non-uniform Zn deposition. For the ρ case, the\nGB,c\nASEI demonstrates exceptional structural integrity, remaining nearly intact during the initial cycle (Fig.\nS9a3). Even after 50 cycles, only trace embryonic cracks are observed (Fig. S9b3), and the majority of\nmicrostructure remains intact (Fig. S9c3). Such high efficiency in dendrite suppression is primarily\nendowed by the combination of high electrochemical kinetics and mechanical strength. For the ASEI\nwith extremely high ρ , however, early delamination, accompanied by numerous short cracks, appears\nGB\nquickly due to the low mechanical strength (Fig. S9a4), which leads to crazing cracking and diffusive\ngrowth of dendrites with further cycling (Fig. S9b4). Meanwhile, the regions appear intact at low\nmagnification (Fig. S9b4) have, in fact, already developed dispersed Zn dendrite nuclei and nano-cracks\n(Fig. S9c4). Such ρ -dependent microstructure evolution and dendrite growth behaviors in ASEI\nGB\nactually inherit the degradation physics in the charging process (presentations about Fig. 5). Importantly,\nfor all ASEIs with varying ρ , no microstructural instabilities—such as grain coarsening or phase\nGB\ntransformation—were detected after cycling, including in the inactive regions near dendrites,\nfragmented ASEI sheets, or crack edges (Figs. S9c2-c4). This confirms the high grain structure stability\nof the current ASEI.\nX-ray diffraction patterns and elemental chemical state examinations using XPS reveal that the\nZnS ASEI holds excellent chemical stability during repeated Zn plating/stripping cycles (Figs. S9d &\ne). As shown, the diffraction peak remains almost unchanged even after 50 cycles, with no disappearing\nor newly generated peaks, except for slight intensity fluctuations caused by sample difference. XPS\nspectra show stable Zn 2p and S 2p chemical states during cycling. These results indicate that the ZnS\nASEI resists side reactions with the electrolyte. In contrast, bare Zn develops strong characteristic peaks\nof Zn SO (OH) ·H O after cycling due to aggravated side reactions.\n4 4 6 2\n4 / 34\nFig. S9 | Grain structure stability and chemical stability of ZnS ASEIs during repeated Zn\nplating/stripping cycles. Top-view SEM image showing the dendrite growth and crack damage\nmorphologies of bare Zn and ZnS_ST_ρ ASEIs after (a) 10 and (b) 50 cycles at 0.5 mA cm-2. High-\nGB\nresolution SEM image showing the localized grain structure of (c1) bare Zn and (c2-c4) ZnS_ST_ρ\nGB\nASEIs after 50 cycles. (d) X-ray diffraction patterns of bare Zn and ZnS_ST_55 ASEI at the initial state\nand after 50 cycles. XPS spectra of bare Zn and ZnS_ST_55 ASEI at the initial state and after 50 cycles\nat binding energies corresponding to (e1) Zn 2p, and (e2) S 2p. The nearly unchanged XRD peaks in\n(d) and stable Zn 2p or S 2p chemical states shown in (e1-e2) prove the high chemical stability10-12.\nComment 1.3: Is there any ZnS dissolution?\nResponse 1.3: We have obtained evidences verifying that the ZnS ASEI possesses exceptional\ninsolubility. Given the thinness of the ZnS layer, reaction with or dissolution into the electrolyte would\ninduce detectable attenuation in its X-ray diffraction peaks. Moreover, reaction with the electrolyte\nwould generate byproducts, such as the Zn SO (OH) ·4H O, compromising the surface morphology\n4 4 6 2\nand grain structure. Interestingly, the ZnS ASEI exhibits nearly unchanged XRD patterns and grain\n5 / 34\nmorphologies after 7-days immersion in the electrolyte (Figs. S2c-d). These constitutes key evidence\nsupporting the insolubility. Further evidence is that the grain morphology and chemistries of ASEI\nremain stable as well in the repeated Zn plating/stripping cycles, even when severe cracking and\nfragmentation occur, as presented in Figs. S9c-e and discussed above (Response 1.2). Such exceptional\ninsolubility and chemical stability contribute significantly to the viability of ZnS in aqueous zinc\nbatteries, and is exactly one of the motivations for selecting it as a model system to investigate the\ncrystallographic microstructure engineering.\nIn the Revised Manuscript, to ensure contextual logical coherence, the insolubility has been\naddressed alongside microstructural and chemical stability as follows (the first paragraph in Page 13):\n…Another key point worth to note is that the ZnS ASEIs exhibit exceptional grain structure\nstability, chemical stability and insolubility during service…\nIn the Revised Supplementary Information, a streamlined discussion clarifying the insolubility\nof ZnS ASEI during repeated cycling has been added as a part of the Extended Discussion entitled\n\"Grain structure stability and chemical stability of ZnS ASEIs during repeated Zn plating/stripping\ncycles\" (Page S3) as follows:\nMeanwhile, the ZnS ASEI exhibits exceptional insolubility during service. Given the thinness of\nthe ZnS layer, dissolution into the electrolyte would induce X-ray diffraction peak attenuation. Reaction\nwith electrolyte would generate byproducts and compromises surface morphology and grain structure.\nHowever, the ZnS ASEI exhibits nearly unchanged XRD pattern and grain morphology after 7-days\nimmersion in the electrolyte (Figs. S2c-d). These confirm the insolubility. Moreover, the stable XRD\npattern, grain morphology and chemical state of ASEIs during repeated Zn plating/stripping cycles\nconstitute the evidence of insolubility as well (Fig. S9).\nFig. S2 | …(c) X-ray diffraction and (d) microstructure morphology before and after 7-days immersion\nin the 2M ZnSO electrolyte, compared between the bare Zn and ZnS_ST_55 ASEI. The nearly\n4\nunchanged diffraction patterns and surface morphology of ZnS ASEI suggest exceptional chemical\nstability and insolubility. This is in contrast to the severe diffraction peak shift and stacked\nZn SO (OH) ·4H O by-product in bare Zn.\n4 4 6 2\n6 / 34\nComment 1.4: Why was ZnS selected as the artificial interface layer?\nResponse 1.4: In this work, ZnS is selected as a model material to investigate the crystallographic\nmicrostructure engineering of ASEI design. The primary motivation lies in its potential application in\nZn metal anode, owing to its acceptable ionic conductivity, electronic insulation, high mechanical\nstrength and chemical stability5-9. Chemical stability encompasses the chemical inertness against side\nreaction and good insolubility.\nIn the Revised Manuscript (the last paragraph of Introduction Section, Page 3), a concise\nstatement on this point is provided as follows:\n\"Here, these issues are discussed in a sphalerite-phase zinc sulfide (ZnS) ASEI served in aqueous\nzinc batteries, as it represents one of the available ASEIs with acceptable ionic conductivity, mechanical\ntoughness, and chemical stability, yet it remains susceptible to dendrite growth26,27.\".\nComment 1.5: I appreciate it's difficult to write in a non-native language! But the writing is not\ngood. A thesaurus has been overused (misused) throughout, and has made it difficult to follow as\na result. Sometimes due to poor grammar, or convoluted phrasing, or just incorrect use of a word.\nAgain, I appreciate the authors are likely non-native speakers, but the authors can make it easier\nfor themselves by not feeling the need to use overtly ostentatious language. The paper needs an\nextensive rewrite to make it readable. Some (of many possible) examples: \"… which may render\nmultiple competitive and/or synergistic electro-chemo-mechanical mechanisms, complexing the\nregulation principles.\" Some of this sentence is fine, but this last bit is not correct. \"Certainly, if the\nimpacts are competitive, it is demanded to delineate the threshold of microstructure characteristic\nthat can effectively reconcile the kinetics strength trade-off\" is faintly comical in how contrived it is\nto seem sophisticated. Also, the word \"doesn't\" appears as an informal contraction in the\nmanuscript.\nResponse 1.5: We appreciate the reviewer's comments. Yes, the language of original manuscript lacked\nnative fluency. In this revision stage, we engaged a native English-speaking professor specializing in\nsolid-state battery materials to refine the text. We really hope that the revised version now can meet\njournal's standards. For instance, the inappropriate expression \"Certainly, if the impacts…strength\ntrade-off\" has been revised as \"Should the impacts exhibit a trade-off relationship, it is necessary to\nidentify the critical threshold of microstructural characteristics that optimally balances mechanical\nstrength and kinetic performance, as exemplified by the regulation of the ρ of ZnS ASEI (the upper\nGB\npart in Fig. 6a).\" (the last paragraph in Page 13). The expression \"a new ASEI design route doesn't\ninvolve chemical composition manipulation\" has been polished to be \"a new ASEI design route that\navoids chemical composition manipulation\" (the first paragraph in Page 3). The initial expression \"…\nwhich may render multiple competitive and/or synergistic electro-chemo-mechanical mechanisms,\n7 / 34\ncomplexing the regulation principles\" has been revised as \"…, which may lead to multiple competitive\nand/or synergistic electro-chemo-mechanical mechanisms that complicate the regulation principles\"\n(the 2nd paragraph in Page 3). The expression \"Herein, a key characteristic of ZnS ASEI's optimal\ncrystallographic microstructure state—predominant in plane (111) orientation—can be identified\" has\nbeen revised as \" Herein, a key characteristic of the optimal crystallographic microstructure state—\npredominant in-plane (111) orientation—of ZnS ASEI can be identified.\" (the first paragraph in Page\n9). More revisions can be found in the updated version.\nComment 1.6: On page 14, the authors claim \"crystallographic microstructure engineering does\nnot involve chemical addition and can be realized in situ during ASEI synthesizing, making this\nroute intrinsically cost-effective and highly practicable.\" This is directly contradicted by their own\nwork, where they have to use a pulsed laser deposition technique in order to control the texturing\nadequately. The authors can't have it both ways: it is either essential to control the ASEI crystal\nstructure, in which case it will be necessary to use sophisticated thin-film deposition techniques,\nor making an artificial surface interface is simple, in which case it can be done via a simple in situ\nelectrochemical deposition. Without experimental evidence, I cannot see how they can make their\ncurrent claim here regarding practicality, and certainly not how it is more practical than simple\nelectrolyte engineering. I think it is fine to broadly argue the merits of artificial anode creation versus\nelectrolyte engineering (which isn't a particularly new set of insights), but this work doesn't really\naddress one of the main limits with artificial SEIs, which was not their quality but rather their ease\nof scalable implementation. PLD isn't exactly industrially practical compared to electrolyte additives.\nTo be honest, I think the whole discussion around figure 6 b is misleading and largely unnecessary,\nand should just be removed.\nResponse 1.6: Thanks for the reminding. PLD employed in this work is indeed not a low-cost process.\nWe apologize for the inappropriate claims and overinterpretation in the original manuscript. In the\nrevised version, terms such as \"low-cost\" and \"highly practicable\" along with associated statements,\nhave been removed.\nWe fully agree with the reviewer's perspective that electrolyte engineering and scalable ASEI\nconstruction technique are research priorities for rechargeable metal batteries. While as unveiled by the\nkey findings of this work and the cases collected in Table S2, crystallographic microstructure design of\ninorganic ASEIs can significantly enhance their functional durability and robustness. For instance, an\nASEI with optimized crystallographic orientation and/or grain size can enhance anode longevity by\nseveral-fold to an order of magnitude compared to conventional ASEIs. Such efficacy rivals or even\nsurpasses that of electrolyte engineering. This finding holds significant implications as it indicates a\nroute to further enhance battery longevity beyond the limitations of electrolyte engineering, especially\nwhen the latter's efficacy proves insufficient. Indeed, a scalable ASEI construction process with precise\n8 / 34\ncrystallographic control is fundamental for implementing this route. Although such a process has not\nyet been realized, it may be not beyond reach. Typically, a TiO ASEI with strong (001) texture was\n2\nsynthesized for Zn anode protection through a simple hydrothermal method by Wang et al.10. Using a\nscalable electrochemical method, Guo et al. optimized the finer grain size of Li Bi ASEI in Li metal\n3\nbatteries11. Developing facile ASEI synthetization and microstructure control processes is a key focus\nof our future work. However, we maintain that clarifying how ASEI crystallographic microstructure\ninfluences its functional robustness is necessary as well, as the underlying principles can guide the\noptimization and selection of synthesis processes.\nFig. 6b provides a comparison in Zn plating/stripping cycling longevity among the Zn anodes\noptimized by different routes, including ASEI crystallographic microstructure engineering, chemical\ncomposition-dependent ASEI design, electrolyte engineering, ASEI orientation optimization and zinc-\nhost regulations. It shows that ASEI crystallographic microstructure engineering has exceptional\nefficacy in improving ECS performance, which rivals or even exceeds that achieved by other routes.\nTo avoid possible misinterpretation, redundant discussions around Fig. 6b in the original manuscript have\nbeen replaced with the following concise and objective presentation (the 2nd paragraph in Page 14,\nRevised Manuscript):\n…Such performance enhancement rivals or even exceeds that achieved by chemical composition-\ndependent ASEI design, electrolyte engineering, ASEI orientation optimization and zinc-host regulation\n(Fig. 6b). This comparison demonstrates the exceptional efficacy of ASEI crystallographic\nmicrostructure engineering in improving ECS performance.\nReferences involved in the above responses:\n1. Chen, K. et al. Flower-shaped lithium nitride as a protective layer via facile plasma activation for\nstable lithium metal anodes. Energy Storage Mater. 18, 389-396 (2019).\n2. Jiang, Y. et al. Artificial Heterogeneous Interphase Layer with Boosted Ion Affinity and Diffusion\nfor Na/K-Metal Batteries. Adv. Mater. 34, 2109439 (2022).\n3. Zhang, D., Li, B., Wang, S. & Yang, S. Simultaneous Formation of Artificial SEI Film and 3D\nHost for Stable Metallic Sodium Anodes. ACS Appl. Mater. Interfaces 9, 40265-40272 (2017).\n4. Wang, Y., Cheng, F., Huang, Y., Cai, C. & Fu, Y. Vertically-oriented growth of MgMOF layer via\nheteroepitaxial guidance for highly stable magnesium-metal anode. Energy Storage Mater. 61,\n102911 (2023).\n5. An, Y. et al. Rational Design of Sulfur-Doped Three-Dimensional Ti C T MXene/ZnS\n3 2 x\nHeterostructure as Multifunctional Protective Layer for Dendrite-Free Zinc-Ion Batteries. ACS\nNano 15, 15259-15273 (2021).\n6. Hao, J. et al. An In‐Depth Study of Zn Metal Surface Chemistry for Advanced Aqueous Zn‐Ion\nBatteries. Adv. Mater. 32, 2003021 (2020).\n9 / 34\n7. Lee, B. et al. Insights into the design of zincophilic artificial protective layers enabling uniform\nnucleation and deposition for stable dendrite-free Zn anodes. J. Colloid Interface Sci. 680, 640-\n650 (2025).\n8. Liu, X. et al. Stabilizing zinc anodes for long-lifespan zinc-nickel battery through the in-situ\nconstruction of zincophilic interface layer. Energy Storage Mater. 58, 311-321 (2023).\n9. Wang, D. et al. Insight on Organic Molecules in Aqueous Zn‐Ion Batteries with an Emphasis on\nthe Zn Anode Regulation. Adv. Energy Mater. 12, 2102707 (2022).\n10. Zhang, Q. et al. Revealing the role of crystal orientation of protective layers for stable zinc anode.\nNat. Commun 11, 3961 (2020).\n11. Shao, Y. et al. Bismuth-Contained Lithiophilic Protective Layer on Lithium Metal Anode In Situ\nGenerated via Electrochemical Method. ACS Sustainable Chem. Eng. 10, 11493-11500, (2022).\n10 / 34\nReviewer #2:\nComments: This manuscript presents a thorough investigation into crystallographic\nmicrostructure engineering of artificial solid-electrolyte interphases (ASEIs) to improve the stability\nof metal anodes. Using ZnS-based ASEIs in aqueous Zn metal batteries as a representative\nsystem, the authors tackle the challenge of dendrite suppression by systematically elucidating the\nrelationships among grain orientation, grain boundary density (ρ ), and the resulting\nGB\nelectrochemical and mechanical properties of ASEIs. The identification of an optimal\nmicrostructure—characterized by a predominant (111) orientation and a critical ρ < 55\nGB,c\nμm/μm2—demonstrates significant cycling performance (3400 cycles, 99.92% Coulombic\nefficiency), marking a notable advancement. The study convincingly argues that crystallographic\noptimization can outperform traditional compositional modifications, offering a potentially universal\nASEI design strategy. This work is of interest and could be considered for publication in Nature\nCommunications after the following critical issues are addressed.\nResponse: Thanks for the kind comments. The following concerns are particularly insightful and have\nbeen seriously considered. Revisions were made accordingly, as highlighted using red font in the\nRevised Manuscript and the Revised Supplementary Information.\nComment 2.1: The ZnS layer fabricated via pulsed laser deposition (PLD) exhibits a thickness of\napproximately 1.5 μm. This value substantially exceeds the conventional thickness range of SEIs,\nwhich are typically on the order of several to tens of nanometers. Thus, referring to this layer as\nan “ASEI” may be conceptually misleading. It would be more appropriate to describe it as a\nmodification layer or an interfacial coating.\nResponse 2.1: It's exactly an insightful comment.\nSEI is generally recognized as an electronically insulating and ionically conducting passivation\nlayer, acted between the electrode and electrolyte (J. Electrochem. Soc 144, L208 (1997), Peled).\nIndeed, the conventional SEIs and ASEIs generally exhibit a thickness of several to tens of nanometers\nto maintain efficient ionic transport. However, to the authors' knowledge, neither the original SEI\nconcept introduced by Peled et al. nor subsequent extensive research has established a definitive\nthickness range or provided a clear physical rationale for the thickness threshold (J. Electrochem. Soc\n144, L208 (1997); J. Electrochem. Soc 126, 2047 (1979)).\nMeanwhile, several leading research groups have recently advanced ASEI thickness to micrometer\nscale, motivated by the pursuit of enhanced mechanical stiffness to mitigate dendrite-induced stress\nconcentration1-6. For instance, Archer's research group (Nat. Energy 3, 889-898 (2018)) engineered a\nmechanically stable Langmuir-Blodgett ASEI in thickness of ~2-3 μm, which could not only stabilize\n11 / 34\nthe Li anode but also can be facilely assembled. Zhou's group (Nat. Commun. 15, 3085 (2024))\ndemonstrated a Li N-rich SEI in thickness of ~5-20 μm, which effectively facilitated interfacial ion\n3\ntransport and simultaneously provide sufficient mechanical stiffness. The research by Lu's group (J.\nAm. Chem. Soc. 145, 22456-22465 (2023)) constructed a 1.8 μm-thick gradient SEI with organic-\nrich surface (CH OC- and C ) and bottom (ZnF ), integrating the merits of fast ionic diffusion and\n2 5 2\nmechanical flexibility.\nIn this study, the thickness of the PLD-deposited ASEI layer was controlled at ~1.5 μm to ensure\nsufficient stiffness while maintaining ionic conductivity, thereby enhancing its mechanical damage\ntolerance and functional durability. A streamlined explanation on the principle of ASEI thickness\nchosen has been added in the Revised Manuscript (the last paragraph in Page 4) as follow: \"Note\nthat the 1.5 μm deposition thickness was chosen to ensure adequate mechanical stiffness and fast ionic\ntransport31\".\nThe authors think that whether calling it \"coating\" or \"ASEI\" does not violate the general\nconnotation of ASEI in the context of battery technology and can be readily understood by readers. For\nexample, in the work demonstrating an optimal ASEI thickness at the micrometer scale, Cui's group\ninterchangeably used the terms \"coating\" and \"ASEI\" (e.g., \"...there existed an optimal coating\nthickness (≈1 µm, 1 mil doctor blade) for the artificial SEI layer...\") (Adv. Mater. 29, 1605531 (2017)).\nWe would appreciate the reviewer's guidance should there be any further considerations on this matter.\nComment 2.2: While the ZnS layer with (111) orientation demonstrates superior mechanical\nrobustness, the underlying Zn metal anode is relatively soft and mechanically weaker. The\nmechanical mismatch at the ZnS/Zn interface could result in uneven stress distribution during\ncycling, potentially introducing localized stress concentrations (e.g., shear and tensile stresses).\nThese may act as mechanical failure initiation sites on the Zn anode and should be thoroughly\nevaluated.\nResponse 2.2: It's a solid suggestion. As schematized in Fig. S4e, the mechanical piercing of dendrites\nresults in high stress concentration in the ASEI layer. Specifically, the stress concentration arises from\ntwo mechanical effects: the direct piercing effect of dendrite, and the deformation mismatch effect\nbetween dendrite and ASEI. During dendrite nucleation and early growth, the stress concentration\ninduced by direct piercing scales proportionally with dendrite height due to the elastic interaction with\nASEI. As the dendrite grows, stress concentration increases quickly to yield the soft dendrite, the\ninteraction with the ASEI transitions to elastic/plastic interaction. Namely the ASEI's strong constraint\nmakes the dendrite tip yield, while the ASEI remains elastic owing to its high strength. This deformation\nincompatibility, manifested as Poisson's ratio difference-induced strain mismatch, introduces extra\nshear constraint between them, which intensifies the stress concentration in ASEI. High stress\nconcertation could trigger mechanical damage in ASEI, featured by crack nucleation, crack propagation\nand delamination from the Zn substrate, ultimately compromising the dendrite-suppressing\n12 / 34\nfunctionality.\nIn the Revised Manuscript (the last paragraph in Page 12), to ensure contextual logical\ncoherence and readability, a concise statement on the mechanism of dendrite-induced high stress\nconcentration has been added as bellow:\n… Low ρ renders limited Zn nucleation sites but a faster growth rate for each nucleus. The\nGB\ngrowing Zn dendrites have a direct piercing effect on ASEI, and the strength mismatch between them\ncould introduce extra shear interactions (Fig. S4e). These effects collectively yield sparsely distributed\nyet intense stress concentrations along GBs (Fig. 5c1) …\nIn the Revised Supplementary Information, an Extended Discussion entitled \"Dendrite-induced\nstress concentration in ASEI\" (Page S2) and Fig. S4e (Page S10) are included, to provide readers with\nin-depth mechanistic insights on the stress concentration in ASEI.\nThe mechanical piercing of dendrites results in high stress concentration in the ASEI layer.\nSpecifically, the stress concentration arises from two mechanical effects: the direct piercing effect of\ndendrite, and the deformation mismatch effect between dendrite and ASEI (Fig. S4e). During dendrite\nnucleation and early growth, the stress concentration induced by direct piercing scales proportionally\nwith dendrite height due to the elastic interaction with ASEI. As the dendrite grows, stress concentration\nincreases quickly to yield the soft dendrite, the interaction with the ASEI transitions to elastic/plastic\ninteraction. Namely the ASEI's strong constraint makes the dendrite tip yield, while the ASEI remains\nelastic owing to its high strength. This deformation incompatibility, manifested as Poisson's ratio\ndifference-induced strain mismatch, introduces extra shear constraint between them, which intensifies\nthe stress concentration in ASEI (Fig. S4e). High stress concertation could trigger mechanical damage\nin ASEI, featured by crack nucleation, crack propagation and delamination from the Zn substrate (Fig.\n5c), ultimately compromising the dendrite-suppressing functionality.\nFig. S4 | …(e) Schematics illustrating the mechanical interaction between dendrite and ASEI: elastic\ninteraction occurs at the initial dendrite nucleation stage, while elastic/plastic interaction renders\ncomplex stress state and high stress as dendrite continue to grow. σ represents the equivalent\neq,ZnS\nstress derived from the normal stress σ and shear stress 𝜏 on ZnS ASEI, where 𝜏 is\nZnS ZnS ZnS\nprimarily caused by the passion's ratio difference between elastic ASEI and plastic dendrite.\nComment 2.3: The manuscript lacks discussion on the chemical stability of the ZnS layer under\nrepetitive Zn plating/stripping. It remains unclear whether the ZnS layer undergoes chemical\n13 / 34\nreactions with the electrolyte or evolves during extended cycling. Addressing this question is crucial\nfor validating the long-term reliability of the engineered interface.\nResponse 2.3: Thanks for the reminding. The chemical stability of ASEI is indeed a critical\nconsideration. This point actually has been verified in the investigation stage through two independent\nexperiments. First, we conducted a 7-days immersion experiment in the electrolyte (Figs. S2c-d). The\nresults show nearly unchanged XRD patterns and surface morphology with no generated byproducts.\nSecond, high-resolution microstructural characterization, crystallographic analysis (via XRD), and\nchemical composition profiling (via XPS) were conducted at multiple Zn plating/stripping cycling\nstages (Fig. S9), which unveil well-retained original grain morphology with no dissolution trace, no\ndisappearing or newly generated diffraction peaks, and stable Zn 2p or S 2p chemical states, respectively.\nGiven the ZnS ASEI's mere 1.5 μm thickness, any obvious reaction with or dissolution into the electrolyte\nwould lead to detectable attenuation of X-ray diffraction peaks, even alterations in chemical state, and\nconsequent degradation of grain morphology. Therefore, the results shown in Figs. S2c-d and Fig. S9 can\neffectively verify the exceptional chemical stability and insolubility of current ASEI. This is exactly\none of the motivations for selecting it as a model system to investigate the crystallographic\nmicrostructure engineering.\nIn the Revised Manuscript (the first paragraph in Page 13), to ensure contextual logical\ncoherence and readability, the microstructural stability, chemical stability and insolubility of ZnS ASEI,\nalong with their implications, are briefly discussed as bellow:\n… Another key point worth to note is that the ZnS ASEIs exhibit exceptional grain structure\nstability, chemical stability and insolubility during service, with no detectable grain coarsening,\nphase transformation, or side reactions with the electrolyte (Figs. S2c-d & S9). This makes cracking\nfollowed by fragmentation the primary mechanism of ASEI consumption. Minimal mechanical damage thus\nendows ZnS_ST_55 ASEI with the lowest consumption rate, thereby enhancing its functional\nrobustness …\nPlease check Responses 1.2 and 1.3 for the explanations of ASEI microstructural stability.\nMoreover, in the Revised Supplementary Information, an Extended Discussion entitled \"Grain\nstructure stability and chemical stability of ZnS ASEIs during repeated Zn plating/stripping cycles\"\n(Page S3) has been added to detail the experimental results and underlying physics.\nComment 2.4: To convincingly demonstrate the practical effectiveness of ZnS coatings in\nsuppressing dendritic growth, symmetric Zn//Zn cell testing should be conducted under higher\nareal capacity conditions. This would better mimic realistic usage scenarios and further validate\nthe claimed performance improvements.\nResponse 2.4: It's a constructive suggestion. Galvanostatic Zn plating/stripping cycling performance\nof bare Zn, Zn@ZnS_x_55, and Zn@ZnS_ST_ρ symmetric cells under a higher areal capacity of 5.0\nGB\n14 / 34\nmAh cm-2 have been provided in the Revised Supplementary Information (Fig. S3a2 and Fig. S8a2).\nFig. S3 | Galvanostatic Zn plating/stripping cycling performance of bare Zn and Zn@ZnS_x_55\nsymmetric cells at (a1) 10 mA cm-2, 1 mAh cm-2, and (a2) 5 mA cm-2, 5 mAh cm-2\n.\nFig. S8 | Galvanostatic Zn plating/stripping cycling performance of bare Zn and Zn@ZnS_ST_ρ\nGB\nsymmetric cells at (a1) 10 mA cm-2, 1 mAh cm-2, and (a2) 5 mA cm-2, 5 mAh cm-2\n.\nAs shown in Fig. S3a2, even under high areal capacity up to 5 mAh cm-2, the trend that cycling\nlife decreases significantly with the weakening of ZnS (111) texture is well maintained, further\ncorroborating the ZnS (111) texture-dictated ECS performance as proposed. Fig. S8a2 again reveals the\nnonmonotonic dependence of cycling life on ρ , further substantiating the existence of the optimal\nGB\nρ ~55 μm/μm2.\nGB,c\nIn the Revised Manuscript, the lifespan-extension effect under a higher areal capacity condition\nhas been addressed in the last paragraph of Page 5 as follows:\n… However, such a lifespan-extension effect deteriorates substantially as the ZnS (111) texture\nweakens, a trend consistently observed irrespective of the current density or areal capacity (Figs. 2a &\nS3a) …\nComment 2.5: A minor issue: Table S1 should include additional critical parameters influencing\nelectrochemical performance, such as electrolyte composition and volume, areal capacity, and\ndepth of discharge. These are essential for enabling proper comparison and reproducibility.\nResponse 2.5: Thanks for the reminders. More parameters that may influence the electrochemical\nperformance, including electrode thickness, electrolyte composition and volume, areal capacity and\ndepth of discharge (DoD), have been supplemented in Table S1 (Revised Supplementary Information,\nPage S18).\n15 / 34\nReferences involved in the above responses:\n1. Kim, M. S. et al. Langmuir-Blodgett artificial solid-electrolyte interphases for practical lithium\nmetal batteries. Nat. Energy 3, 889-898 (2018).\n2. Pokharel, J. et al. Manipulating the diffusion energy barrier at the lithium metal electrolyte\ninterface for dendrite-free long-life batteries. Nat. Commun. 15, 3085 (2024).\n3. Xu, W. et al. Fluoride-Rich, Organic-Inorganic Gradient Interphase Enabled by Sacrificial\nSolvation Shells for Reversible Zinc Metal Batteries. J. Am. Chem. Soc. 145, 22456-22465 (2023).\n4. Pathak, R. et al. Fluorinated hybrid solid-electrolyte-interphase for dendrite-free lithium\ndeposition. Nat. Commun. 11, 93 (2020).\n5. Liu, Y. et al. An Artificial Solid Electrolyte Interphase with High Li‐Ion Conductivity, Mechanical\nStrength, and Flexibility for Stable Lithium Metal Anodes. Adv. Mater. 29, 1605531 (2016).\n6. Han, D. et al. A non-flammable hydrous organic electrolyte for sustainable zinc batteries. Nature\nSustain. 5, 205-213 (2021).\n16 / 34\nReviewer #3:\nComments: This manuscript presents an impressive story in the exploration of new aSEI design\nroute. Taking the ZnS aSEI served in aqueous zinc batteries as a paradigm, the optimal\nmicrostructure state—predominant in-plane (111) orientation coupled with a critical grain boundary\ndensity ρGB,c was identified by systematical microstructure modulation. This optimization\noutperforms most reported chemical composition-dependent aSEI designs, delivering\nunprecedented effectiveness in dendrite suppression, anode lifespan extension and\nplating/stripping cycling stabilization. It indicates the emergence of a transformative solution to the\nlong-standing bottleneck of efficacy limitation and cross-strategy incompatibility in conventional\naSEI designs. Indeed, having elucidated the mechanisms of how microstructural characteristics\naffect electrochemical kinetics and mechanical strength, a new aSEI design route—\ncrystallographic microstructure engineering—was proposed and rationalized. These findings\nconstitute a respectable progress, with notable innovations in aSEI design concept and anode\nperformance improvement, in the field of rechargeable metal batteries. It can meet the standards\nof Nature Communications, and is likely to engage both academic and industrial audience in\nenergy science community. I would like to support its publication.\nResponse: Thanks for the kind comments. The insightful concerns have been seriously considered.\nRevisions have been highlighted using red font in the Revised Manuscript and the Revised\nSupplementary Information.\nComment 3.1: The majority of claims in the manuscript have been well rationalized. But there is\nstill a critical issue which may deserve the authors' attention. The implementation of\ncrystallographic microstructure engineering in aSEI inevitably involves synergistic optimization of\nmultiple microstructure characteristics. Thus, key questions remain: How does the modulation\nsequence of different microstructural characteristics affect the outcomes, and what principles on\nthe modulation sequence should be followed to achieve the 'truly' optimal microstructure state?\nSince the optimal state of a microstructure characteristic should be interdependent with others, the\ncoordinated optimization of multiple characteristics therefore must be affected by their modulation\nsequence. It may attain a fake or artifactual optimal state if the modulation sequence is improper.\nJust taking the ZnS aSEI as an example: if one first identifies the optimal grain boundary density\nρc under a non-(111) orientation, then fixes ρc while searching for the optimal orientation, would\nthe resulting ‘optimal’ microstructure state and anode performances differ from those determined\nin current work? In this regard, to ensure the reliability and practicality of crystallographic\nmicrostructure engineering in aSEIs, it is critical to elucidate the principles of the modulation\nsequence and interdependencies of multiple microstructure characteristics.\n17 / 34\nResponse 3.1: It's exactly a solid suggestion. Indeed, an inevitable issue in the implementation of\nsynergistic optimization of multiple crystallographic microstructure characteristics is establishing the\nregulation sequence. An improper regulation sequence may lead to a fake or artifactual optimal state. The\nprimary cause of this issue is the interdependent mechano-electrochemical effects of specific microstructural\ncharacteristics. For instance, the effects of grain boundary density (ρ ) on ionic conductivity and\nGB\nmechanical strength are largely affected the prevailing grain orientation and texture. Alternatively, the effects\nof some microstructure characteristics are intrinsically dictated by the chemical composition and lattice\nstructure, such as the optimal grain orientation that balances electrochemical kinetics and mechanical\nstrength. This calls for a universal principle clarifying the regulation sequence.\nIn the Revised Manuscript (the first paragraph of 'Crystallographic microstructure engineering\nfor ASEI' Section, Page 13), a streamlined discussion has been provided as follows to clarify regulation\nsequence of multiple microstructure characteristics.\n… Note that identifying the optimal ASEI microstructure state should follow the principle—\nprioritizing characteristics dictated by the material's chemical composition, then those dependent on\nthese identified ones (Fig. S10). In the ZnS case, the (111) orientation is intrinsically dictated by its\nchemical composition and sphalerite-phase lattice, thus necessitating to be identified with priority.\nWhile the effect of regulating ρ may depend on the prevailing crystal orientation and should therefore\nGB\nbe determined subsequently. Failure to follow this sequence may yield a pseudo-optimal microstructural\nstate.\nComment 3.2: Line 189-191: The statement “…the high elastic modulus and low Schmid factor…\nimprove the elastic limit and the resolved shear stress for defect multiplication” is really confusion.\nLow Schmid factor renders low resolved shear stress on slip plane, thus requiring higher applied\nstress for defects activity.\nResponse 3.2: We sincerely apologize for the oversight. As the reviewer noted, our original intention\nwas to convey that a lower Schmid factor reduces the resolved shear stress on slip plane, which helps\nto suppress defects multiplication such as dendrite growth-induced cracking. The statement (the last\nparagraph in Page 6, Revised Manuscript) has been corrected as: \"Such ZnS (111) texture-imparted\nhigh mechanical strength and creep resistance can be primarily attributed to the high elastic modulus\nand low Schmid factor of (111) crystal facet (Figs. 2h & i), which improve the elastic limit and reduce\nthe resolved shear stress for defect multiplication, respectively.\".\nComment 3.3: Line 70: Non-standard reference formatting.\nResponse 3.3: Thanks for the reminding. This has been corrected in accordance with the journal's\nrequirement (the 4th paragraph of Introduction section, Page 3 of the Revised Manuscript). The\ncitation formats throughout this manuscript have also been carefully checked.\n18 / 34\nComment 3.4: Line 92: What does “CE” means?\nResponse 3.4: Thanks for the reminding. \"CE\" refers to the coulombic efficiency, which is a specialized\nterm to evaluate electrochemical reversibility. It has been defined at its first occurrence (the first\nparagraph of Introduction section, Page 2 of the Revised Manuscript). The manuscript has been\nthoroughly reviewed to avoid similar oversights.\nComment 3.5: Line 93: Should it be stated as \"most chemical composition optimized\" or \"chemical\ncomposition optimized\"?\nResponse 3.5: It's a good suggestion. The statement (the last paragraph in Page 3, Revised\nManuscript) has been revised as: \"Such efficacy rivals, or even surpasses that achieved by most\nchemical-composition dependent strategies, proving a new ASEI design route—crystallographic\nmicrostructure engineering.\"\nComment 3.6: It is suggested to delete the less-used abbreviations, such as “PLD”, to enhance\nthe readability.\nResponse 3.6: Thank you for the kind reminding. Such redundant descriptions have been eliminated for\nbrevity. Meanwhile, the English has also been professionally polished to enhance readability.\n19 / 34\nReviewer #4:\nComments: This work proposes that the crystallographic structural design of an artificial solid\nelectrolyte interphase (ASEI) can modulate Zn anode behavior, ultimately achieving enhanced\ncycling stability. The findings may provide some useful insights into interfacial engineering\nstrategies for Zn-based batteries, which could be published in Nature Communications. However,\nseveral important issues should be addressed as follows:\nResponse: We sincerely appreciate the kind comments and suggestions. The concerns have been\naddressed point by point. Revisions were made accordingly, as highlighted using red font in the\nRevised Manuscript and Revised Supplementary Information.\nComment 4.1: The study demonstrates performance improvement of Zn anodes using a\ncrystallographically tailored ZnS_ST(111)_55 ASEI. However, given the broader claim of ASEI\ndesign, the authors should discuss the applicability of this approach to other metallic anodes.\nCan the same crystallographic design strategy be extended to systems beyond Zn —e.g., Li, Na, or\nMg? Some discussion or hypothetical extension would strengthen the conceptual universality.\nResponse 4.1: In this work, the experimental researches addressed the high efficacy of ASEI\ncrystallographic microstructure engineering in improving Zn anode stability, which entails regulating\nthe typical microstructural characteristics of ZnS ASEI to the optimal states based on the principle of\nintegrating or balancing electrochemical kinetics and mechanical strength. Indeed, the previous\nmanuscript was limited by the lack of extended discussion on the broad applicability of the proposed\nASEI design route to other metallic anodes. The reviewers' feedback brings this to our attention. Thank\nyou sincerely for this.\nAlthough synergistic regulation of multiple crystallographic microstructural characteristics within\na single ASEI, to the authors' knowledge, remained unexplored prior to this work, several studies have\nreported the optimization of individual microstructural characteristics in specific ASEIs. This insight\noffers a potential shortcut for validating the broad applicability of ASEI crystallographic microstructure\nengineering. Specifically, if there are enough cases in which targeted regulation of individual\nmicrostructural characteristics in specific ASEIs—involving the principle of synergizing or balancing\nmechanical strength and electrochemical kinetics—can effectively improve anode performance, the\nbroad applicability of this design route can be thereby confirmed. In this logic framework, three\nfundamentals must be met by the cases. (i) The principle of integrating or balancing mechanical strength\nand electrochemical kinetics should be followed or be the underlying mechanism in ASEI's\nmicrostructure modulation. (ii) Significant improvement in anode cycling stability is rendered by the\nmodulation. (iii) The cases meeting the first two fundamentals must encompass ASEIs with diverse\nchemistries and applied in various anode systems, such as in Zn, Li, Na, and Mg anodes. Simultaneously\nengineering multiple crystallographic microstructural characteristics within a single ASEI, although\n20 / 34\nhighly desirable, is not mandatory.\nGuided by this logic, we systematically retrieved the experimental records and theoretical\ninvestigations related to the crystallographic microstructure regulation of ASEIs. The representative\ncases are collected in Table. S2. Surprisingly, a number of ASEI design cases, involving those served\nin Zn, Li, Na, and Mg metal anodes, indeed meet the above three fundamentals. For instance, Zhou et\nal. demonstrated that a highly (001)-orientated Li N ASEI\n3\nextends the cycling life of Li metal anode by ~1.25-fold compared to the randomly oriented counterpart,\ndue to the integration of high mechanical modulus and ionic conductivity1. A comparative analysis of\nNa₂S ASEIs with controlled grain sizes—as reported by Yu et al. and Yang et al.—reveals that a critical\nsize of ∼50 nm can markedly improve the cycling stability of Na anode, outperforming coarser\nmicrostructure2,3. Moreover, Fu et al. verifies that the Mg-MOF-74 ASEI with a strong (101) texture\nenables a dramatic improvement in the cycling lifespan of Mg anode, which is attributed to the\noptimized Mg2+ diffusion kinetics4. These paradigms collectively confirm the broad applicability of\ncrystallographic microstructure engineering across various metal anode systems.\nTo address these insights, an additional discussion has been incorporated in the manuscript as\nfollows (the last paragraph in Page 14, Revised Manuscript) to validate the broad applicability and\ntransferability of crystallographic microstructure engineering.\nNote that crystallographic microstructure engineering also holds significant potential for\napplication to ASEIs with diverse chemistries across various metal anode systems. This can be\nsupported by the documented experimental cases and/or theoretical analyses in which variations in\nASEI microstructure always dramatically affect anode cycling stability, as summarized in Table S2.\nSpecifically, three fundamentals are shared among these cases. First, a significant extension in anode\nlifespan is always achieved at a specific ASEI microstructure state17,21. Second, the underlying\nmechanisms often involve, directly or indirectly, the principle of ASEI crystallographic microstructure\nengineering—integrating and balancing electrochemical kinetics and mechanical strength44. Third,\nalthough most efforts have focused on regulating individual crystallographic microstructural features,\ncases meeting the first two fundamentals encompass ASEIs with diverse chemistries and applied in\nvarious anode systems, including sulfides, oxides, nitrides, fluorides, or metal-organic complexes, used\nin Zn, Li, Na, and Mg anodes (Table S2). These suggest that advancing crystallographic microstructure\nengineering in more ASEIs—enabling synergistic optimization of key microstructural characteristics\nthrough scalable, low-cost processes—holds promise for enhancing the performance of next-generation\nmetal batteries.\nComment 4.2: Although the manuscript emphasizes crystallographic microstructural rather than\nchemical composition-dependent control, it remains unclear whether this crystallographic\nmodulation is effective only for ZnS, or potentially applicable to other compounds. The authors\n21 / 34\nshould comment on whether similar performance could be realized using other sulfides or even\nnon-sulfide materials.\nResponse 4.2: This is definitely a solid suggestion highly relevant to the previous one.\nActually, the cases summarized in Table S2 have encompassed the ASEIs with diverse chemistries,\nincluding sulfides, oxides, nitrides, fluorides, or metal-organic complexes, utilized in Zn, Li, Na, and\nMg anodes. For instance, Wang et al. achieved a 2-fold lifespan extension in Zn metal anode by\nengineering the crystallographic microstructure of TiO ASEI, transforming the orientation from\n2\nrandom to a predominant (001) texture5. For the TiN ASEI served in zinc anode, Alshareef et al. found\nthat constructing a prominent (200) orientation can enhance the anode lifespan by up to twentyfold,\ncompared to the randomly oriented counterparts6. In the case of LiF ASEI in Li metal anode, refining\nthe grain size from ~300 nm to ~10 nm leads to 8-fold lifespan extension, as revealed by Lucht et al.7.\nFollowing the logic framework addressed in Response 4.1, these paradigms, although in which only\nindividual microstructural features are regulated for each compound, collectively provide a shortcut for\nvalidating the applicability of ASEI crystallographic microstructure engineering to other compounds.\nTo streamline the logic and avoid redundant content, discussions on the applicability of ASEI\ncrystallographic microstructure engineering to other compounds with diverse chemistries across various\nanode systems have been consolidated into a unified section (the last paragraph in Page 14, Revised\nManuscript) as follows:\nNote that crystallographic microstructure engineering also holds significant potential for\napplication to ASEIs with diverse chemistries across various metal anode systems … cases meeting the\nfirst two fundamentals encompass ASEIs with diverse chemistries and applied in various anode systems,\nincluding sulfides, oxides, nitrides, fluorides, or metal-organic complexes, used in Zn, Li, Na, and Mg\nanodes (Table S2) ...\nComment 4.3: The ASEI layer in this work is controlled to be ~1.5 μm. Is there a critical thickness\nthreshold? Please discuss how ASEI thickness affects the performance overall.\nResponse 4.3: It's really an insightful concern. ASEI thickness critically affects anode cycling\nperformance by simultaneously regulating ionic-transport rate and mechanical stiffness, the latter of\nwhich is necessary to resist dendrites-induced cracking and thus suppress their growth. An excessively\nthin ASEI cannot provide sufficient mechanical stiffness, whereas an overly thick one is susceptible to\ncompromise ionic-transport rate8-10. The trade-off between ion-transport kinetics and mechanical\nstiffness as functions of ASEI thickness is expected to delineate a critical thickness that optimizes its\nfunctional robustness. For example, Cui's group identified the optimal thickness of ~1 μm for the Cu N-\n3\nstyrene butadiene rubber composite ASEI, by synergizing electrochemical kinetics and mechanical\nproperty8. For the hybrid ASEI containing LiF, Sn, and Sn-Li alloy composites, the optimal thickness\nof ~25 μm was confirmed, as revealed by Zhou's group10. For the current ZnS ASEI, the thickness is\n22 / 34\ncontrolled at ~1.5 μm to balance mechanical stiffness and ionic conductivity. Specifically, the high\nelastic modulus and low Schmid factor enabled by predominant in-plane (111) orientation (Figs. 2h &\ni), combined with the micron-scale thickness, collectively yield a high stiffness. The ionic conductivity\nexamination demonstrated that the 1.5 μm-thick ZnS ASEI (Fig. 2e), with synergistic optimization of\ngrain orientation and size, can achieves an exceptional ion transport rate of ~1.65×10-4 S m-1.\nThis study focuses on how the crystallographic microstructural characteristics of ASEI affects\ndendrite growth and anode performances, and how to achieve the optimal states of multiple\ncharacteristics. Although ASEI thickness is a key property affecting its functional robustness and\ndeserves in-depth elucidation, it is essentially a geometric property rather than a crystallographic\ncharacteristic targeted in current work. To enhance the clarity of the core argument, a simplified\nstatement addressing the control of ASEI thickness has been incorporated in the Revised Manuscript\nas follows (the last paragraph in Page 4):\n… Note that the 1.5 μm deposition thickness was chosen to ensure adequate mechanical stiffness\nand fast ionic transport31…\nMeanwhile, an Extended Discussion entitled \"Effects of ASEI thickness on anode performance\"\nhas been added in the Revised Supplementary Information (Page S4) to elucidate more physics\nfor the possible existence of the optimal ASEI thickness as follows:\nASEI thickness critically affects anode cycling performance by simultaneously regulating ionic-\ntransport rate and mechanical stiffness, the latter of which is necessary to resist dendrites-induced\ncracking and thus suppress their growth. An excessively thin ASEI cannot provide sufficient mechanical\nstiffness, whereas an overly thick one is susceptible to compromise ionic-transport rate6-8. Thus, the\ntrade-off between ion-transport kinetics and mechanical stiffness as functions of ASEI thickness is\nexpected to delineate a critical thickness that optimizes its functional robustness. For example, Cui's\ngroup identified the optimal thickness of ~1 μm for the Cu N-styrene butadiene rubber composite ASEI,\n3\nby synergizing electrochemical kinetics and mechanical property8. For the hybrid ASEI containing LiF,\nSn, and Sn-Li alloy, the optimal thickness of ~25 μm was confirmed by Zhou's group7. For the current\nZnS ASEI, the thickness is controlled at ~1.5 μm to balance mechanical stiffness and ionic conductivity.\nSpecifically, the high elastic modulus and low Schmid factor enabled by predominant in-plane (111)\norientation (Figs. 2h & i), combined with the micron-scale thickness, collectively yield a high stiffness.\nThe ionic conductivity examination demonstrated that the 1.5 μm-thick ZnS ASEI (Fig. 2e), with\nsynergistic optimization of grain orientation and size, can achieve an exceptional ion transport rate of\n1.65×10-4 S m-1. Indeed, this study focuses on how the crystallographic microstructural characteristics\nof ASEI affects dendrite growth and anode performances, and how to achieve the optimal states of\nmultiple characteristics. Although ASEI thickness is a key property affecting its functional robustness\nand deserves in-depth elucidation, it is essentially a geometric property rather than a crystallographic\ncharacteristic targeted in the current work. This warrants systematic investigation in future studies.\nComment 4.4: The grain size distributions in Figs. S2 and S5 are central to the argument\n23 / 34\nregarding grain boundary (GB) effects. However, the method used to extract these distributions is\nnot clearly described. Since GBs are central to the discussion, direct and spatially resolved\ntechniques such as EBSD would provide more conclusive insights. Please clarify the current\nmethod and consider incorporating more direct microstructural evidence.\nResponse 4.4: As shown in Figs. S2a & S5b, the current PLD-synthesized ZnS ASEIs exhibits\nrelatively uniform grain size distribution, with no bimodal mixture of ultra-large or small grains. To\nensure accurate results, grain size distribution was determined following the steps below:\n(i) Select clear high-magnification SEM images, then measure the size of all grains within the\nrandomly chosen areas using ImageJ software. In this step, the size of a grain is calculated as the\nmean of two randomly drawn perpendicular diameters.\n(ii) After ensuring that over 350 grains were measured for each ASEI, calculate the frequency within\neach size interval to obtain grain size distribution.\n(iii) Compare the average grain size obtained by the above manual counting with that measured by the\nstandard Heyn linear intercept method (ASTM E112-13), ensuring a relative error less than 5%.\nIn the Methods Section of Revised Manuscript (the 2nd paragraph in Page 16), a statement has\nbeen supplemented to clarify this.\n… The distribution and mean value of grain size for each ASEI were determined by manually\nmeasuring the dimensions of over 350 spatially consecutive grains. The average grain size was validated\nagainst that determined by the standard Heyn linear intercept method (ASTM E112-13) to ensure\naccuracy …\nThe detailed procedure of grain size measurement has also been added in the Revised\nSupplementary Information as a part of the Extended Discussion entitled \"Grain size distribution of\nASEIs and impact on cycling performance\" (Page S5).\nIndeed, high-resolution EBSD/TKD or TEM characterizations of ASEIs is highly desirable, but is\nlimited by significant experimental difficulties. First, the grain size in some of the current ASEIs has\nbeen reduced to ~30 nm, surpassing the resolution limit of conventional EBSD technique. Second, the\nPLD-synthesized ZnS material is very susceptible to electron irradiation-induced damage and\ndecomposition. This renders the preparation of high-quality thin foils via electron/ion beam-based\ntechniques (for TKD/TEM observations) extremely challenging, and simultaneously makes it almost\nimpossible to stably withstand either the prolonged exposure in TKD mapping or the high-energy\nelectron beam in TEM characterization. As exemplarily shown in Fig. R1, which were captured while\ntrying to cut TKD foils, ZnS layer decomposed almost instantly even under a weak ion-beam of only\n500 pA (10 kV). While, a TKD mapping process generally takes more than 30 minutes, and TEM\nobservation is usually performed at a voltage of more than 100 kV.\n24 / 34\nFigs. R1 | Real-time monitoring of electron irradiation-induced rapid damage in PLD-synthesized\nZnS. (a) Snapshots at varying irradiation times. (b) Complete video documentation of the damage\nprogression.\nActually, high-magnification SEM images (Figs. 1b & S5a) can also clearly present the\nmicrostructure and grain size of the current ASEIs to a certain extent. Fig. S5d presents the only TEM\nimage obtained through rapid exposure on a relatively thick specimen, which remains heavily noise-\ndegraded due to electron irradiation-induced damage, precluding clear resolution of grain morphology.\nComment 4.5: It is unexpected that a modest increase in ρGB from 35 to 40 leads to doubled\ncycle life and other performance gains. Meanwhile, Fig. S5b shows that ZnS_ST_35 has a much\nbroader grain size distribution compared to other samples. Since similar ρGB values can achieved\nwith different grain size profiles, please discuss whether the performance improvement is solely\nattributable to ρGB, or if the size distribution also plays a critical role.\nResponse 4.5: It's really a careful observation. The authors fully agree with the reviewer that the breadth\nof ASEI grain size distribution is another potential factor, alongside the ρ , affecting its functionality\nGB\nand failure behavior. The underlying mechanism likely stems from that a broader grain size distribution\nleads to more heterogeneous development among dendrites. Specifically, for an ASEI with broader\ngrain size distribution, ion transport and deposition in the region with coarser grains are confined to\nlimited GB channels, leading to form locally sparser but faster-growing dendrites. Such thrive dendrites\nact as spearheads progressing short-circuiting. In short, the broader the grain size distribution, the more\nheterogeneous the dendrites growth and thus the quicker the short circuit.\nTo show the differences in the distribution breadth and mean value of grain size across ASEIs, the\ndistribution histograms were replotted using unified x-axis interval (Fig. S5b). Indeed, ZnS_ST_35\n25 / 34\nexhibits a broader grain size distribution than others due to the prolonged growth duration during the\nsynthesis process. Such broad distribution may promote the development of dendrite protrusions by\nexacerbating nucleation heterogeneity (Fig. 5a1), which holds a potential factor responsible for the\ndramatic lifespan shrinkage compared to the ZnS_ST_40 system. However, beyond this factor, a more\nstriking distinction responsible for the lifespan shrinkage is that over 70% grains in ZnS_ST_35 ASEI\nare larger than those in ZnS_ST_40 ASEI, i.e., the dramatic ρ difference between them (Fig. S5b).\nGB\nFig. S5 | Microstructure of a set of ZnS_ST_ρ ASEIs: (a) Top-view SEM images and (b) grain size\nGB\ndistributions …\nDecoupling the individual effects of distribution breadth and average value of grain size on cycling\nlife demands controlled experiments and simulations—a endeavor that merits a dedicated, systematic\ninvestigation beyond the workload of this paper. Therefore, a streamlined discussion as bellow has been\nadded in the Revised Manuscript (the last paragraph in Page 12) to address that the broader grain\nsize distribution of ZnS-ST-35 ASEI is another potential factor, alongside the low ρ , which is\nGB\nresponsible for the formation of sparse dendrite protrusions and the dramatic lifespan shrinkage\ncompared to the ZnS_ST_40 system.\nMoreover, the broader grain size distribution of the ZnS-ST-35 ASEI is also a potential factor\npromoting dendrite protrusion formation since it exacerbates nucleation heterogeneity (Fig. S5b).\nFurthermore, in the Revised Supplementary Information, an Extended Discussion entitled\n\"Grain size distribution of ASEIs and impact on cycling performance\" (Page S5) has been provided to\ndetail the above physics.\nFig. S5b shows the differences in the distribution breadth and mean value of grain size across\nASEIs. Interestingly, ZnS_ST_35 ASEI exhibits a broader grain size distribution than others due to the\nprolonged growth duration during the synthesis process. Such broader grain size distribution indicates\nthe mixture of the coarser and finer grains. In the plating/stripping process, ion transport and deposition\nin the region with coarser grains are confined to limited GB channels, leading to form locally sparser\nbut faster-growing dendrites, i.e., exacerbated heterogeneities in nucleation and growth renders the\ndevelopment of 'bump-like' dendrite protrusions (Figs. 5a & S9). Such thrive dendrites act as spearheads\nprogressing short-circuiting. These suggests that the broader grain size distribution of ZnS_ST_35 ASEI\nis another potential factor, alongside the ρ , dictating the formation of dendrite protrusions and the\nGB\ndramatic lifespan shrinkage compared to the ZnS_ST_40 system. Decoupling the individual effects of\ngrain size distribution breadth and ρ on cycling life demands controlled experiments and simulations,\nGB\nwhich demands dedicated and systematic investigations.\nComment 4.6: How does the ASEI layer evolve during cycling? Are there structural changes (e.g.,\nroughening, cracking, dissolution)? If operando or ex-situ monitoring has been performed (e.g.,\noperando cross-sectional imaging, post-cycling cross-sectional SEM), please present them to\nsupport the working mechanism of ASEI clarified in this study.\nResponse 4.6: The concerns are absolutely insightful. Indeed, the working mechanism and performance\nof ASEIs is related to its structural changes and chemical stability during cycling, possibly involving\nmicrostructure damage (e.g., cracking and roughening), grain structure variation, chemical stability,\nand solubility.\nHere, this issue is systematically addressed through two sets of independent experiments. First,\nmicrostructure morphology and grain structure characterizations (via SEM), crystallographic analysis\n(via XRD), and chemical composition profiling (via XPS) were conducted at multiple plating/stripping\ncycling stages of ASEIs with varying ρ (Fig. S9), to unveil the evolutions of damage, grain structure\nGB\nand chemical property of ASEI layer. Second, the XRD pattern and microstructure morphology before\nand after 7-days immersion in the electrolyte are compared to clarify the dissolution behavior (Figs.\nS2c-d). The results collectively prove that, although dendrite-induced cracking evolves significantly\nduring cycling and varies with ρ , the ZnS ASEIs exhibit exceptional grain structure stability, chemical\nGB\nstability and insolubility. These highlight the degradation kinetics, namely cracking followed by\nfragmentation constitutes the primary consumption mechanism during service. The minimal mechanical\ndamage in the ZnS_ST_55 ASEI results in the lowest consumption rate, thereby achieving high\nfunctional robustness.\nThe evolutions of ρ -dependent dendrite growth and ASEI damages actually inherit the\nGB\ncorresponding mechanisms in the charging process (presentations about Fig. 5). To ensure contextual\nlogical coherence and avoid redundancy, a streamlined discussion clarifying the dominant role of\ndendrite-induced cracking in ASEI consumption has been incorporated into the Revised Manuscript\n(the first paragraph in Page 13) as follows.\n…Another key point worth to note is that the ZnS ASEIs exhibit exceptional grain structure\nstability, chemical stability and insolubility during service, with no detectable grain coarsening,\nphase transformation, or side reactions with the electrolyte (Figs. S2c-d & S9). This makes cracking\nfollowed by fragmentation the primary mechanism of ASEI consumption. Minimal mechanical damage thus\nendows ZnS_ST_55 ASEI with the lowest consumption rate, thereby enhancing its functional\nrobustness…\nIn the Revised Supplementary Information, an Extended Discussion entitled \"Grain structure\nstability and chemical stability of ZnS ASEIs during repeated Zn plating/stripping cycles\" (Page S3)\n27 / 34\nhas been added to detail ASEI evolutions during cycling, sequentially including the mechanical\ndamages and grain structure, the chemical stability and the dissolution as below:\nThe ASEI's grain structure and chemical stability is another critical prerequisite to ensure the\nfunctional sustainability and thus the electrode cycling stability. Here, microstructure evolution of\nZnS_ST_ρ ASEIs over repeated Zn plating/stripping cycles is investigated (Fig. S9). In contrast to\nGB\nthe thriving dendrite developed in bare Zn (Figs. S9a1, b1 & c1), ZnS ASEIs exhibit different degrees\nof dendrite suppression. Owing to sluggish electrochemical kinetics, the lowest-ρ ASEI develops\nGB\nultra-large Zn protrusions (Figs. S9a2 & b2), with the original microstructure retaining in the\nsurrounding regions (Fig. S9c2), suggesting highly non-uniform Zn deposition. For the ρ case, the\nGB,c\nASEI demonstrates exceptional structural integrity, remaining nearly intact during the initial cycle (Fig.\nS9a3). Even after 50 cycles, only trace embryonic cracks are observed (Fig. S9b3), and the majority of\nmicrostructure remains intact (Fig. S9c3). Such high efficiency in dendrite suppression is primarily\nendowed by the combination of high electrochemical kinetics and mechanical strength. For the ASEI\nwith extremely high ρ , however, early delamination, accompanied by numerous short cracks, appears\nGB\nquickly due to the low mechanical strength (Fig. S9a4), which leads to crazing cracking and diffusive\ngrowth of dendrites with further cycling (Fig. S9b4). Meanwhile, the regions appear intact at low\nmagnification (Fig. S9b4) have, in fact, already developed dispersed Zn dendrite nuclei and nano-cracks\n(Fig. S9c4). Such ρ -dependent microstructure evolution and dendrite growth behaviors in ASEI\nGB\nactually inherit the degradation physics in the charging process (presentations about Fig. 5). Importantly,\nfor all ASEIs with varying ρ , no microstructural instabilities—such as grain coarsening or phase\nGB\ntransformation—were detected after cycling, including in the inactive regions near dendrites,\nfragmented ASEI sheets, or crack edges (Figs. S9c2-c4). This confirms the high grain structure stability\nof the current ASEI.\nX-ray diffraction patterns and elemental chemical state examinations using XPS reveal that the\nZnS ASEI holds excellent chemical stability during repeated Zn plating/stripping cycles (Figs. S9d &\ne). As shown, the diffraction peak remains almost unchanged even after 50 cycles, with no disappearing\nor newly generated peaks, except for slight intensity fluctuations caused by sample difference. XPS\nspectra show stable Zn 2p and S 2p chemical states during cycling. These results indicate that the ZnS\nASEI resists side reactions with the electrolyte. In contrast, bare Zn develops strong characteristic peaks\nof Zn SO (OH) ·H O after cycling due to aggravated side reactions.\n4 4 6 2\nMeanwhile, the ZnS ASEI exhibits exceptional insolubility during service. Given the thinness of\nthe ZnS layer, dissolution into the electrolyte would induce X-ray diffraction peak attenuation. Reaction\nwith electrolyte would generate byproducts and compromises surface morphology and grain structure.\nHowever, the ZnS ASEI exhibits nearly unchanged XRD pattern and grain morphology after 7-days\nimmersion in the electrolyte (Figs. S2c-d). These confirm the insolubility. Moreover, the stable XRD\npattern, grain morphology and chemical state of ASEIs during repeated Zn plating/stripping cycles\nconstitute the evidence of insolubility as well (Fig. S9).\n28 / 34\nFig. S2 | …(c) X-ray diffraction and (d) microstructure morphology before and after 7-days immersion\nin the 2M ZnSO electrolyte, compared between the bare Zn and ZnS_ST_55 ASEI. The nearly\n4\nunchanged diffraction patterns and surface morphology of ZnS ASEI suggest exceptional chemical\nstability and insolubility. This is in contrast to the severe diffraction peak shift and stacked\nZn SO (OH) ·4H O by-product in bare Zn.\n4 4 6 2\nFig. S9 | Grain structure stability and chemical stability of ZnS ASEIs during repeated Zn\nplating/stripping cycles. Top-view SEM image showing the dendrite growth and crack damage\n29 / 34\nmorphologies of bare Zn and ZnS_ST_ρ ASEIs after (a) 10 and (b) 50 cycles at 0.5 mA cm-2. High-\nGB\nresolution SEM image showing the localized grain structure of (c1) bare Zn and (c2-c4) ZnS_ST_ρ\nGB\nASEIs after 50 cycles. (d) X-ray diffraction patterns of bare Zn and ZnS_ST_55 ASEI at the initial state\nand after 50 cycles. XPS spectra of bare Zn and ZnS_ST_55 ASEI at the initial state and after 50 cycles\nat binding energies corresponding to (e1) Zn 2p, and (e2) S 2p. The nearly unchanged XRD peaks in\n(d) and stable Zn 2p or S 2p chemical states shown in (e1-e2) prove the high chemical stability10-12.\nComment 4.7: In Fig. 5d, the MC/MD simulations suggest Zn preferentially deposits along GBs\nin low ρGB ASEI, while flat Zn deposition occurs underneath the ZnS ASEI in high-ρGB cases.\nHowever, these trends seem to differ from some experimental observations. Please clarify the\nconnection and discrepancies herein.\nResponse 4.7: We sincerely appreciate the comment.\nFig. 5d presents the ρ -dependent Zn2+ transport and deposition processes. Indeed, if only ion\nGB\ntransport and deposition uniformity are considered, higher ρ should lead to more uniform deposition,\nGB\nand thus weaker dendrite and ASEI degradation are expected. However, experimental observations\nrevealed that the weakest dendrite growth and minimal ASEI damage occur in the ρ ~55 m/m2\nGB,c\ncase, not at higher ρ (Fig. 5). This arises an apparent logical discrepancy. The underlying physics of\nGB\nthis lies in that ASEI degradation is affected by both deposition uniformity and mechanical strength,\nand these two factors exhibit mutually exclusive dependence on ρ (Figs. 4a-f and the last two\nGB\nparagraphs in Page 9 of the Revised Manuscript). This renders a non-monotonic dependence of\nASEI damage on ρ —dendrite-induced crack erosion initially weakens and then intensifies with\nGB\nincreasing ρ (Fig. 5). For the cases with excessively high ρ , even there are relatively uniform initial\nGB GB\ndeposition and high-density dendrite nuclei (the right panel, Fig. 5d), the low mechanical strength\nenables the existing dendrites to readily breach the ASEI as well, resulting in dense microcracks and\ndiffuse dendrite (Figs. 5a5 & c3).\nIn the Revised Manuscript, following a detailed presentation of dendrite growth characteristics\nand corresponding ASEI damage evolving with ρ (the last paragraph in Page 11), the underlying\nGB\nmechanisms for the excessively low ρ case, the excessively high ρ case, as well as the ρ case\nGB GB GB,c\nhave been systematically clarified (the last paragraph in Page 12). Specifically, clarifications about\nthe apparent discrepancy that excessively high ρ enables uniform deposition but still induces severe\nGB\nASEI damage include the following：\n\"The mutually exclusive dependencies of electrochemical kinetics and mechanical strength on ρ\nGB\nsuggest that the ρ is delineated by the trade-off between ECS contribution factors ... Upon reaching\nGB,c\nthe ρ (Fig. 5a3), only a few discrete cracks appear, with no exposed dendrites, indicating effectively\nGB,c\nsuppressed dendrite growth, which are responsible for the improved ECS performance (Figs. 4g-h). The\nappearance of such 'near-ideal' morphology signifies two service characteristics of ASEI that enabled\nby ρ : (i) a homogeneous Zn deposition process alleviating stress concentration, and (ii) improved\nGB,c\n30 / 34\nyield and damage thresholds preserving structural integrity and thus functional stability. When ρ\nGB\nexceeds the ρ (Fig. 5a4), however, abundant short cracks interact and connect into crazing cracks,\nGB,c\nwith diffuse dendrite proliferation appearing from delamination sites. As the ρ improves to an\nGB\nexcessively high value (Fig. 5a5), delamination-induced diffuse dendrites destroy the structural\nintegrity of ASEI, significantly reducing the lifespan and CE of asymmetric cells (Figs. 4g-h) …\" (the\nlast paragraph in Page 11)\n\"As simulated by molecular dynamics, Zn2+ transport and early-stage deposition are ASEI GB-\ndependent processes (Figs. 5d & S7) … Improving ρ can increase the uniformity of Zn deposition by\nGB\nproviding more transport channels and nucleation sites11. However, excessively high ρ reduces the\nGB\nmechanical strength, which enables extensive nucleation of short cracks, eventually leading to\nwidespread crack erosion and diffuse dendrites (Fig. 5c3). In particular, upon approximating ρ ~55\nGB,c\nm/m2, there are sufficient GBs for ionic transport and Zn nucleation, while maintaining relatively\nhigh damage. This represents the optimal trade-off between electrochemical kinetics and mechanical\nstrength, providing a unique opportunity to resist both 'bump-like' protrusions and diffuse dendrite\nformations (Fig. 5c2), thereby enabling ZnS_ST_55 ASEI to maintain good structural integrity …\" (the\nlast paragraph of Page 12)\nComment 4.8: In the DFT calculation of adsorption energy, was the charge of adsorbed Zn atom\nconsidered? Or simply a neutral Zn atom?\nResponse 4.8: The charge of adsorbed Zn atom was not considered in the DFT calculations. Actually,\nemploying a neutral atom in adsorption-energy calculation is a well-established and widely accepted\napproach for evaluating SEI layer adsorption behavior. For instance, based on the adsorption calculation\nof a neutral Zn atom on both hopeite SEI and bare Zn, Guo et al. demonstrated a much stronger Zn\nadsorption capability (binding energy of -2.82 eV) for the former12. Wang et al. simulated the adsorption\nof neutral Zn atom on TiO ASEI and Zn surfaces, and unveiled the stronger affinity of TiO (100) facet\n2 2\naccordingly5. Yuan et al. analyzed the neutral K atom adsorption at the V S and V S /graphene atomic\n3 4 3 4\ninterfaces, confirming that the graphene-V S (020) interface exhibits better adsorption capability13.\n3 4\nUndoubtedly, incorporating the charge of adsorbed Zn atom might better represent the actual reaction\nprocess. Nevertheless, the key factor governing Zn adsorption is the chemical state and surface\naccessibility of the adsorbent's active sites, which are directly dictated by the crystal orientation. For\ninstance, the ZnS (111) orientation has a higher S-site density compared with other orientations, thereby\nenabling superior electrochemical kinetics (Fig. 1a). This suggests that when an adatom is adsorbed\nonto a sufficiently large adsorbent surface, adatom's charge may not significantly affect the adsorption\ntrends across different crystallographic orientations. In other words, adatom adsorption behavior across\nvarious crystal facets can serve as a robust descriptor for identifying the electrochemical kinetics-\npreferred orientation of current ZnS ASEI.\nMoreover, it must be noted that the VASP framework with plane-wave basis set does not allow\n31 / 34\nassigning charges to an individual adsorbate; instead, it only allows modification of the total number of\nelectrons through the NELECT tag, which introduces a homogeneous background charge. This, in turn,\ninevitably induces long-range spurious Coulomb interactions between neighboring periodic structures,\nthereby compromising the reliability of such calculations—the limitation explicitly acknowledged in\nthe VASP manual. Nevertheless, we have still made extensive efforts on charged-atom adsorption\ncalculations, by introducing background charges and considering implicit solvation effect with\nVASPsol program14-21. However, the calculations have proved to be computationally intractable and\nsuffered from severe convergence difficulties, attributable to the inherent methodological limitation\ndescribed above.\nImportantly, the grain orientation/texture-dependent variation of ZnS ASEI's electrochemical\nkinetics that predicted from the adsorption energies of neutral Zn atoms on different crystal facets agrees\nwell with experimental results (Figs. 2c-d), which validates the simulation approach again. A statement\nin the calculation of charge density difference is supplemented in the Methods section of Revised\nManuscript (Page 17):\n…The charge density difference distribution was calculated as:\n   (2)\nZnsubstrate Zn substrate\nwhere  ,  , and  represent the total charge density of the adsorption structure, the\nZnsubstrate Zn substrate\ncharge density of single Zn atom, and the charge density of the substrate17,34,52…\nReferences involved in the above responses:\n1. Chen, K. et al. Flower-shaped lithium nitride as a protective layer via facile plasma activation for\nstable lithium metal anodes. Energy Storage Mater. 18, 389-396 (2019).\n2. Jiang, Y. et al. Artificial Heterogeneous Interphase Layer with Boosted Ion Affinity and Diffusion\nfor Na/K-Metal Batteries. Adv. Mater. 34, 2109439 (2022).\n3. Zhang, D., Li, B., Wang, S. & Yang, S. Simultaneous Formation of Artificial SEI Film and 3D\nHost for Stable Metallic Sodium Anodes. ACS Appl. Mater. 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Surface modification using heptafluorobutyric acid to produce highly stable Li metal\nanodes. Nat. Commun. 14, 2883 (2023).\n20. Zhang, H. et al. Catalytic activity of violet phosphorus-based nanosystems and the role of\nmetabolites in tumor therapy. Nat. Commun. 15, 6783 (2024).\n21. Zhang, R. et al. Novel in situ SEI fabrication on Zn anodes for ultra-high current density tolerance\nenabled by electrical excitation–conjugation of iminoacetonitriles. Energy Environ. Sci. 18, 1011-\n1026 (2025).\n33 / 34\nReviewer #5:\nComments: I co-reviewed this manuscript with one of the reviewers who provided the listed\nreports. This is part of the Nature Communications initiative to facilitate training in peer review and\nto provide appropriate recognition for Early Career Researchers who co-review manuscripts.\nResponse: We sincerely appreciate for your help and support.\n34 / 34"}, {"round": 2, "reviewer_comments": {"reviewer_1": "I am happy with the quality of the response, particularly the new Figure S9 experiments.", "reviewer_2": "The authors have carefully addressed the comments raised in the last round. I recommend the publication of this work.", "reviewer_3": "My raised issues have been well addressed. In my opinion, the revision in the present form can be published in this Journal now.", "reviewer_4": "The authors have adequately addressed my previous concerns with clear and sufficient explanations, and the overall quality of the manuscript has improved. Nevertheless, since the title has been revised to emphasize the Zn anode, it would be advisable to further refine the narrative to ensure consistency with this focus, particularly in the abstract and introductory sections. Such adjustments would help the manuscript convey a more coherent and well-aligned message to the readers.", "reviewer_5": "I co-reviewed this manuscript with one of the reviewers who provided the listed reports. This is part of the Nature Communications initiative to facilitate training in peer review and to provide appropriate recognition for Early Career Researchers who co-review manuscripts."}, "author_response": ""}]

Decision letter