bluuebunny/crossref_metadata_2025 huggingface dataset:
Nucleation Behavior of Pitting and Evolution of Stripping on Lithium Metal Batteries
Authors: Zhang Hanrui , Ulusel Mert , Shi Feifei
Published: December 2024

The stripping reaction of lithium will greatly impact the cyclability and safety of Li metal batteries. However, lithium pits' nucleation and growth, the origin of uneven stripping, are still poorly understood. In this study, we analyze the nucleation mechanism of Li pits and their morphology evolution with a large population and electrode area (>0.45 cm2). We elucidate the dependence of pit size and density on current density and overpotential, which is aligned with classical nucleation theory. With laser scanning confocal microscope, we reveal the preferential stripping on certain crystal grains and a new stripping mode between pure pitting and stripping without pitting. Descriptors like circularity and the aspect ratio (R) of pit radius to depth are used to quantify the evolution of lithium pits in three dimensions. As pits grow, growth predominates along the through-plane direction, surpassing the expanding rate at the in-plane direction. After analyzing more than 1000 pits at each condition, we validate that the overpotential is inversely related to the pit radius and exponentially related to the rate of nucleation. With this established nucleation-overpotential relationship, we can better understand and predict the evolution of surface area and roughness of lithium electrodes under different stripping conditions. The knowledge and methodology developed in this work will significantly benefit lithium metal batteries' charging/discharging profile design and the assessment of large-scale lithium metal foils. DOI of publication: 10.1021/acsami.4c01530

Acknowledgments: H.Z., M.U., and F.S. thank the support from the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the US Department of Energy through the Advanced Battery Materials Research Program. F.S. thanks the support from the National Science Foundation under Grant No. 2239690.
Case Dependent Metal Dissolution in Li/NMC Batteries
Authors: Merrill Laura C , Gruenwald Hannah Kay , McBrayer Josefine , Fritzsching Keith J.
Published: December 2024

Though active materials (electrolyte, electrodes) drive the performance of batteries, the non-active materials (current collector, case material) and cell format (e.g., pouch cell, coin cell) can also influence battery performance. Many next-generation battery systems implement high theoretical capacity electrodes with wide operating voltages to enable high energy density batteries. To achieve this, Li metal anodes are often paired with high voltage, Ni-rich LiNixMnyCo1-x-yO2 (x ≥ 0.6, “NMC”) cathodes. Many focus on the development of electrolyte formulations that can effectively cycle Li metal with high Coulombic efficiency while maintaining electrochemical stability at the cathode material. These electrolytes are typically based on high, or localized-high, concentrations of lithium bis(fluorosulfonylimide) (LiFSI). Electrolytes based on LiFSI are suspected to be incompatible with both Al current collectors and stainless steel cathode caps, and typically the stainless steel cathode cap is coated with Al to mitigate corrosion.

Here we explore the effect of inactive cell components on Li/NMC battery performance. We investigate mechanistic pathways of case and current collector metal dissolution and the influence of the inactive cell components on NMC transition metal dissolution in both high and localized high concentration electrolytes. We combine electrochemical experiments with ex-situ nuclear magnetic resonance spectroscopy and X-ray fluorescence experiments to track the metal dissolution within the electrolyte with cycling. We also explore the prevalence of galvanic corrosion when two dissimilar metals are in electrical contact with each other (e.g., Al current collector and the steel coin cell case) in each electrolyte. We find that the localized high concentration electrolyte has greater amounts of metal dissolution when cycled in stainless steel compared to the diluent-free high concentration electrolyte, suggesting the addition of the diluent solvents drives the material incompatibility with typical stainless steel coin cell parts.

SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525
(Invited) Mechanisms Governing Lithium Metal and Alloy Anodes in Solid-State Batteries
Authors: McDowell Matthew Todd
Published: December 2024

Solid-state batteries offer the promise of improved energy density and safety compared to lithium-ion batteries, but electro-chemo-mechanical evolution and degradation of materials and interfaces can play an outsized role in limiting their performance. Here, I will present my group’s recent work on understanding structural evolution, interfacial dynamics, and chemo-mechanics in solid-state batteries with both lithium metal and alloy-based anodes. Lithium metal batteries are especially beneficial if used in an “anode-free” configuration in which there is no lithium initially present at the anode current collector. Using X-ray tomography, cryo-FIB, and finite-element modeling, we show that lithium metal anode-free solid-state batteries are intrinsically limited by current concentrations at the end of stripping due to localized lithium depletion. This causes accelerated short circuiting compared to lithium-excess cells. Based on these results, the beneficial influence of metal alloy interfacial layers on controlling lithium evolution and mitigating contact loss from localized lithium depletion will be introduced and discussed. In the second part of the talk, the characteristics of dense, foil-based alloy anodes are introduced. Alloy foils such as aluminum and tin are shown to exhibit improved interfacial stability and better long-term cycling in solid-state batteries compared to liquid-cell batteries due to reduced solid-electrolyte interphase formation. A new design for multiphase aluminum foil alloy anodes is introduced, in which microstructural control over the foil is shown to play a key role in significantly improving reversibility in solid-state batteries. This anode design mitigates chemo-mechanical degradation and offers a paradigm that does away with slurry coating, potentially reducing manufacturing costs. The influence of stack pressure on electrode evolution is investigated. Taken together, these findings show the promise of both lithium metal and alloy anodes for solid-state batteries, with divergent reaction mechanisms giving rise to different operating conditions necessary for each class of materials.
Ion Transport Enhancement Mechanism in Polymer/Ceramic Composite Electrolyte with High-Entropy Li-Garnet
Authors: Ock Jiyoung , Lehmann Michelle , Fu Zhezhen , Wang Yangyang , Bhattacharya Amit , Wang Tao , Dai Sheng , Clement Raphaele J , Sokolov Alexei P. , Chen Xi Chelsea
Published: December 2024

Given the growing demand for electrification, delivering safe, high power, and high energy in lithium-ion batteries is a key challenge. One possible approach is incorporating Li-ion conductive ceramics into a polymer electrolyte matrix. Benefiting from both components, composite electrolytes may deliver high safety, improved ionic conductivity, enhanced electrochemical stability, and feasible construction for solid-state batteries. Specifically, it is crucial to understand and verify the ion transport enhancement mechanism in such a composite electrolyte, as the conductivity in the electrolytes directly affects the overall cell performance and the electrolyte design principles for these systems may change.

In this work, we investigate the ion transport enhancement mechanism in composites made with a single-ion conducting (SIC) polymer electrolyte with high-entropy Li-garnet (HE-LLZO) micron-sized powders. We use broadband dielectric spectroscopy (BDS), thermal gravimetric analysis (TGA), rheology measurement and proton nuclear magnetic resonance (1H NMR) to understand the ion transport kinetics in the composites. At 30 °C, 30 wt% HE-LLZO composites with SIC polymer showed almost 8-fold enhancement in conductivity. The addition of HE-LLZO leads to the different degree of polymerization compared to that of the pure polymer, implying that the substantial amount of unpolymerized monomer facilitated the conductivity in the composites. To further investigate the reaction mechanism in the composites, Fourier transform infrared (FT-IR) spectroscopy results will be presented along with 1H NMR data. Electrochemical properties and cell performance will be compared to further illustrate the effects of HE-LLZO on the composite.

Acknowledgements

This work was supported as part of the Fast and Cooperative Ion Transport in Polymer-Based Materials (FaCT), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences at Oak Ridge National Laboratory under contract DE-AC05-00OR22725.
Composite Lithium and Thick Cathode for High-Energy Long-Cycling Lithium-Sulfur Batteries
Authors: Yu Sicen , Wang Shen , Miao Qiushi , Hui Zeyu , Hyun Gayea , Peng Zhi , Holoubek John , Yu Xiaolu , Gao Junwei , Yang Jihui , Liu Ping , Liu Jun
Published: December 2024

Lithium-sulfur (Li-S) batteries are recognized as a promising candidate for next-generation energy storage systems due to their high theoretical energy density and the abundance of sulfur. However, achieving a long-cycling Li-S battery with a specific energy capacity more than 300 Wh kg−1 presents several challenges, notably lithium metal pulverization induced by non-uniform stripping leading to pit formation and subsequent dendritic deposition. This detrimental cycle exacerbates cell shorting and capacity degradation, particularly under conditions of high electrode loading and low electrolyte condition. To address this problem, we developed a composite lithium metal anode that incorporates nanometer-sized carbon particles uniformly dispersed throughout. This design promotes more uniform lithium stripping by intercepting the uneven growth of pits with the carbon particles. The following deposition of lithium on these carbon particles demonstrates improved uniformity compared to surfaces with irregular pits. As a result, the composite lithium demonstrated a pulverization rate significantly slower than that of commercial lithium, extending Li-S battery cycle life threefold when integrated into batteries with sulfurized polyacrylonitrile (SPAN) cathodes operating at an areal capacity of 8 mAh cm−2. Additionally, we present a strategy to further enhance Li-S battery energy density by increasing the active mass of the cathode, exemplified by a SPAN cathode with an areal capacity of 8 mAh cm−2 and an active-material-ratio of 96wt%, showcasing superior cycling stability.
Interfacial and Electrolyte Solution Reactions at Nickel-Rich Electrodes
Authors: Jones Kieran , Denison Benjamin , McNulty Rory , Walsh Darren Anthony , Newton Graham , Johnson Lee R
Published: December 2024

The demand for secondary batteries has rapidly grown, driven by the societal transition to electric and hybrid modes of transportation, with the lithium-ion battery finding extensive application throughout the energy storage industry. To attain the energy density required to meet the needs of society, research efforts have shifted to pushing the voltage limits of the cell and the use of high nickel contents, for example, LiNi0.8Mn0.1Co0.1O2 (NMC811) and LiNiO2. These nickel-rich layered metal oxides offer increased capacity, and also limit or entirely remove the need for expensive and unsustainable cobalt in the cell. Despite their promise, these nickel-rich electrodes are known to decompose at high voltages, 4.2 V-4.5 V depending on nickel content, with nickel’s oxidation state changing from +4 to +2, forming a rock salt-like structure, and evolving oxygen. The redox and structural changes occurring in the bulk materials are well documented, but the interfacial and electrolyte solution reactions are less well understood.

Here we consider how the surface chemistry of the nickel-rich electrodes changes during cycling and how this may impact degradation at the surface. Specifically, we track the formation and decomposition of surface products quantitatively. These events are compared to the potentials at which oxygen is released from the cell, monitored using online electrochemical mass spectrometry, to unravel degradation reactions of the electrolyte solutions. We have combined a range of methods including nuclear magnetic resonance spectroscopy, gas chromatography–mass spectrometry, and fluorimetry to understand electrolyte degradation at NMC811 electrodes and have been successful in identifying vinylene carbonate in extracted electrolyte, among other components. These data confirm previous reports that NMC811 is able to form vinylene carbonate in situ. Vinylene carbonate is added to lithium-ion cells to stabilise the graphite negative electrode, including in next generation nickel-rich cells, but due to its formation within NMC811 cells, we show its addition is not required. Finally, we consider how vinylene carbonate forms within the cell and unpick the reactive species responsible for its production. In particular, singlet oxygen has been proposed to be released from the NM811 electrodes into the electrolyte solution where it can act as an oxidant. This reaction has been explored using photocatalysts and here we consider the validity of this approach and the reaction of singlet oxygen with the electrolyte solution.
New Hybrid Nano-Architecture of Sulfur Electrode for Lithium-Sulfur Batteries
Authors: Ezzedine Mariam , Jardali Fatme , Florea Ileana , Sorin Costel
Published: December 2024

Lithium-Sulfur batteries have the potential to provide a much greater energy storage capacity than current Lithium-ion batteries. However, Lithium-Sulfur batteries are hampered by challenges arising from the cell level, such as poor conductivity of sulfur, its volume expansion, and the lithium polysulfides shuttle effect. The technology developed in our lab overcomes these fundamental challenges by implementing an innovative electrode architecture that exploits the properties of vertically aligned carbon nanotubes (VACNTs). The hierarchical-assembled-nanostructured battery positive electrode is based on carbon nanotube carpets grafted by 100% sulfur nanomaterial. Coupling it with metallic lithium as negative electrode results in high energy and power, and long-life Lithium-Sulfur battery (Figure 1). The positive electrode topology enables to store more electrical charge more rapidly than any other commercial electrode, positively impacting the power and energy storage capacity of the battery. The Lithium-Sulfur batteries exclude inactive components (such as binders/additives essential for traditional Lithium-ion batteries), thus eliminating the “dead weight” found in the today’s batteries.

Electrochemical performance tests have shown that the Lithium-Sulfur batteries developed in our work have substantially improved capacity performance, stability and cycle life compared to conventional Lithium-Sulfur batteries. At a discharging rate of 2C (i.e., 30 minutes), the cells have shown a stable specific capacity of 400 mAh g-1 over 1000 cycles.
Minimized Li-Ion Coordination Diluent Differentiating Dual-Anion-Derived Solid Electrolyte Interphase Towards Long-Life Lithium Metal Batteries
Authors: Wang Donghai , Li Guoxing
Published: December 2024

Rechargeable lithium (Li) metal batteries face persistent challenges in maintaining stable electrochemical performance, attributed to Li metal's high reactivity and the SEI's instability. Electrolyte composition plays a crucial role in reducing parasitic reactions at the Li metal anode and establishing a stable SEI. In this study, a novel fluorinated cyclic ether was synthesized, exhibiting enhanced electrochemical stability and minimizing Li-ion coordination capability. Its role in manipulating SEI formation was demonstrated, showcasing a bilayer SEI with a Li2O-rich inner layer and a LiF-rich outer layer, ensuring impressive stability and reversibility of Li metal anodes. The developed electrolyte showed significant enhancement in calendar life and cycling stability of Li (50 µm)||NMC811 (4 mAh/cm2) cells, leading to prototype pouch cells with a remarkable cycling stability of 80% capacity for up to 470 cycles, achieving 410 Wh/kg. This work highlights the potential of electrolyte engineering in advancing next-generation Li metal batteries towards high-energy-density applications.
On the Calendar Life of Li Metal Batteries
Authors: Zhang Ji-Guang
Published: December 2024

Significant progresses have been made on the long-term cycle life of lithium (Li) metal batteries (LMBs) in recent years. However, far less progress has been reported on the calendar life of LMBs. Here we will give an overview on the main challenges and progresses in this filed. A perspective on the path towards long-term calendar life of LMBs will also be discussed. The main mechanism for the limited calendar life of LMBs is the chemical (instead of electrochemical) reaction between electrolyte and Li metal anode (LMA) during storage. These reactions are controlled by the chemical reactivity of electrolyte with Li and the surface area of Li exposed to the electrolyte before long term storage. Li has the lowest reductive potential (-3.04 V vs. standard hydrogen electrode) among all anode materials and is also the most reactive anode against non-aqueous electrolyte used in batteries. The reaction rate is mainly controlled by the design of electrolyte. Therefore, develop an electrolyte that exhibits a minimal reaction rate with the LMA and can form a stable SEI is the most critical factor in the calendar life of LMBs. Compared with graphite based Li ion batteries (LIBs) or even silicon based LIBs, significant volume change and generation of porous Li structure (including stacks of solid electrolyte interphase and “dead” Li) formed before long term storage leads to very large surface area of Li anode, therefore accelerates degradation of Li anode. An optimized cell pressure can enhance the formation of large Li particles, reduce dendrite growth and amount of electrolyte which can directly react with Li, therefore extent the calendar life of LMBs. In addition to electrolyte selection and minimize the exposure of LMA to electrolyte, several approaches that may extend the calendar life of LMBs for their large-scale applications will also be discussed in this presentation.
(ECS Charles W. Tobias Young Investigator Award Address) Lithium Oxide Content in the Li Metal Anode Solid Electrolyte Interphase Drives High Coulombic Efficiency
Authors: Gallant Betar M.
Published: December 2024

Despite remarkable improvements in Li cycling Coulombic efficiency (CE) in recent years, Li anodes still cannot meet the >99.9% CE needed for >1,000 cycle life. This shortfall arises from uncontrolled reactivity at the solid electrolyte interphase (SEI) and its resulting properties, leading to inhomogeneous plating and stripping, continuous electrolyte consumption, and loss of active Li inventory. Despite progress in electrolyte design, the lack of precise SEI understanding hinders attempts to rationally design an improved interface towards bridging remaining gaps in CE.

Recent advancement in quantitative chemical analysis of cycled Li anodes has enabled unprecedented understanding of the origin of capacity loss. Pioneering work by Meng et al. demonstrated the method of titration gas chromatography (TGC) for quantifying the amount of metallic Li0 which becomes entrapped in the electrode residuals over repeated cycling.1 The authors showed that Li0 is mainly responsible for capacity loss at intermediate values of CE, and decreasing Li0 is therefore effective for improving performance. As CE becomes very high, however, losses become dominated by the SEI formation itself.2

This talk will describe our efforts to build upon and advance chemical titration by coupling to gas chromatography (GC) and other liquid-phase assays, which has enabled tracking of an extended array of key SEI phases and their proportions over cycling. Beyond Li0, such methods enable accurate resolution of capacity loss as stranded phases to semicarbonates (ROCO2Li), lithium carbide (Li2C2), olefins (RLi), LiF, and P-containing phases, as well as total Li loss, which allow for compositional trends with CE to be revealed. In a prior work,3 we achieved chemical resolution of up to ~70% of the total capacity loss and ~33% of SEI phases, yet still with significant unknown phase contributions. Recently, we have further advanced these titration techniques to quantify an additional key SEI phase, lithium oxide (Li2O),4 which substantially improves upon these numbers. Statistical analysis of correlations between major ionic and organic phases and CE unambiguously reveal that Li2O content is the most strongly predictive of high CE, even moreso than LiF content—widely asserted to be a uniquely beneficial SEI component—or decreasing Li0. By designing several new O-rich and low-F or F-free electrolytes that achieve highly competitive CE breaching 99%, we reveal a compelling electrolyte design landscape based on oxygenation, rather than fluorination.

Fang, J. Li, M. Zhang et al., Nature 2019,572, 511–515.

M. Hobold, J. Lopez, R. Guo, et al., Nature Energy 2021, 6, 951-960.

M. Hobold and B. M. Gallant, ACS Energy Letters 2022, 7, 3458-3466.

M. Hobold, C. Wang, K. Steinberg et al., Nature Energy 2024 (published ASAP).
Highly Li-Concentrated Ionic Liquid Electrolytes Enable High Stability of LiNiO2
Authors: LIU Huazhen , Maeda Hiroki , Hwang Jinkwang , Matsumoto Kazuhiko
Published: December 2024

Since the commercialization of lithium-ion batteries (LIBs) in 1991, LIBs have widely served as a power supply, from consumer electronics and electric vehicles to large-scale energy storage systems. The surge in energy markets, especially the expanding demand for electric vehicles, highlights the urgent need for LIB technologies that provide high energy density, durability, and cost-effectiveness. This drives the expectations of cobalt-free LiNiO2 as positive electrode, which possesses a low cost and an impressively high theoretical energy density (1050 Wh kg−1) for future use.1
However, the commercial application of LiNiO2 is blocked by ongoing issues such as Ni dissolution, structural disordering, and particle cracking, resulting in a low reversible specific capacity, low cyclability, and safety risk.2 Moreover, the use of LiPF6-containing carbonate-based electrolytes makes Ni dissolution drastic due to the attack by HF, which is produced by hydrolysis of LiPF6.3 Exploring electrolytes containing chemically stable salts, such as Li[FSA] ([FSA]− = bis(fluorosulfonyl)amide), becomes an attractive option to enhance cycling stability and mitigate parasitic reactions.

In this study, Li[FSA]-based ionic liquids (ILs) electrolytes including two different cations ([C2C1im]+ = 1-ethyl-3-methylimidazolium, [C3C1pyrr]+ = N-methyl-N-propylpyrrolidinium) are investigated for their performance toward LiNiO2 cathode. 1 mol dm−3 LiPF6-EC/DMC (1:1 v/v) is chosen as the baseline electrolyte. All the IL electrolytes exhibit enhanced cycle performance than the baseline electrolyte, especially highly concentrated [C3C1pyrr]-based electrolytes, reaching a capacity retention of 73.1% after 500 cycles. The surface morphology and chemical characterization reveal the stable cathode electrolyte interphase formed on the LiNiO2 cathode, which is capable of suppressing Ni dissolution and alleviating capacity fade. Moreover, Al corrosion behavior is examined in different electrolytes, which reveals the Al current collector corrosion is mitigated in the highly concentrated [C3C1pyrr]-based electrolyte.

References

[1] T. Deng, X. Fan, L. Cao, J. Chen, S. Hou, X. Ji, L. Chen, S. Li, X. Zhou, E. Hu, D. Su, X. Yang and C. Wang, Joule, 2019, 3, 2550-2564.

[2] E. Quisbert, F. Fauth, A. Abakumov, M. Blangero, M. Guignard, and C. Delmas, Small, 2023, 19, 2300616.

[3] R. Pan, E. Jo, Z. Cui, and A. Manthiram, Adv. Funct. Mater., 2023, 33, 2211461.
Data-Driven Understand of High Entropy Rocksalt Type Li-Ion Battery Cathodes
Authors: Wang Lin , He Zhengda , Ouyang Bin
Published: December 2024

High entropy battery materials (HEBMs) have rapidly emerged in recent years. They offer new pathways for achieving excellent electrochemical performance and show promise in reducing reliance on critical metals, such as Ni and Co. Specifically, high entropy disordered rocksalt type (HE-DRX) cathodes have demonstrated exceptional rate performance attributed to enhanced disorder. In this presentation, we will share a dataset comprising 18810 DFT-computed high entropy disordered rocksalt type (HE-DRX) Li-ion battery cathode materials. Our computational investigation comprehensively explores the entire combinatorial space of 27 typical metal species and various Li or F contents present in DRX cathodes. Building on our previous research, which revealed enhanced rate capability by minimizing chemical short-range order, we will present our interpretation of design principles aimed at creating more stable and more disordered HE-DRX cathodes. Eventually, we will also demonstrate our global machine-learning model that can predict the stability of any HE-DRX cathode composition with an error of less than 5 meV/atom.
Chemical Prelithiation of Silicon Oxide Anodes for Improved Performance in Lithium-Ion Batteries
Authors: Bonneux Gilles , Feng Kun , Moeremans Boaz , D'Haen Jan , Ruttens Bart , Safari Momo , Van Bael Marlies K.
Published: December 2024

Si/SiOX-based materials possess significant potential as an anode in Li-ion batteries, due to their high capacity, stable cycling performance and the volume expansion buffering of the SiOX matrix upon lithiation of silicon nanodomains. However, one of the main challenges is their low initial coulombic efficiency (ICE), due to SEI formation and irreversible parasitic reactions which trap Li ions inside the electrode matrix or at the interface. Prelithiation aims to compensate for the large initial irreversible capacity losses, which can be achieved by introducing active lithium directly into the anode material before cycling.

Through chemical prelithiation, the electrode coating or active material powder is brought in contact with a reactive Li-containing precursor solution via immersion, which allows a direct reaction at the surface. The precursor system ideally requires a sufficiently low redox potential to achieve (partial) prelithiation of the SiOX matrix, while minimizing full Si lithiation and Li plating at the electrode surface. Lithium-Arene complexes dissolved in (cyclic) ether solvents have been shown to have adequate reducing strength (0.2-0.3V vs. Li/Li+) to allow these redox reactions.

In this study, the effects of chemical prelithiation on the battery performance are evaluated inside a half-cell, mainly focusing on the initial cycles. Additionally, the effect of prelithiation on the morphology and composition of the electrode (active) material will be investigated using electron microscopy (SEM) and X-ray diffraction (XRD), including the effect of air exposure on the phase stability. Furthermore, the chemical state of the sample surface is studied, giving deeper insights into its interfacial reactivity and composition. Ultimately, this study aims to create a better understanding of the advantages and disadvantages of this prelithiation method on Si/SiOX-based anodes, paving the way for the development of more efficient lithium-ion batteries.
Electrochemical Reactions of Graphite Fluoride Electrodes in Ionic Liquids
Authors: Ito Yuta , Yoshii Kazuki , Takeuchi Tomonari , Okumura Toyoki
Published: December 2024

Li-graphite fluoride (CF
x
) primary batteries show the highest energy density (2180 Wh kg−
1) among commercialized Li primary batteries, long life storage, and wide operating temperature range, and are the power sources for medical equipment, stand-alone devices, remote keyless systems, and space crafts. Recently, Li-CF
x
cells could be used as secondary batteries1 and are attracting attention as next-generation storage batteries with high energy density. Current problems of conventional Li-CF
x
batteries are safety issues due to using flammable organic electrolytes and short cycle life originated from oxidative decomposition of organic solvents while using as secondary batteries. In this study, we focused on the application of ionic liquids which shows nonvolatile, nonflammable, and wide electrochemical potential window. However, there had been no previous reports of Li-CF
x
battery operation using ionic liquids.

In Li-CF
x
primary batteries with organic electrolytes, solvent and Li+ co-intercalate into CF
x
layer to form an intermediate product and that decomposes to LiF and amorphous carbon (intermediate mechanism).2 Because of the strong interaction between organic solvent and Li+, the solvated Li+ can diffuse into the bulk of the CF
x
. The slow desolvation within the CF
x
layer contributes to the small and dispersed crystallization of LiF, and CF
x
can react completely.3 In the case of ionic liquids, however, Li+ and CF
x
may react directly due to the lack of solvent, resulting in localized crystallization of LiF, inhibiting subsequent Li+ intercalation and preventing CF from reacting completely.

Therefore, in this study, we focused on shortening the diffusion distance of Li+ and made the CF
x
particles finer to submicron size and the electrochemical reaction of CF
x
with Li+ ions were successfully carried out completely in ionic liquids. In this presentation, we will report the fundamentals on the electrochemical reactions of CF
x
electrodes in ionic liquids, including how the components of ionic liquids influence on the electrode potential of CF
x
. The realization of Li-CF
x
batteries using ionic liquids will expand the range of applications with batteries at the environments (undersea, subterranean, and outer space) where conventional batteries have been difficult to be used.

Y. Ito, et al., Chem. Mater., 34, 19, 8711, (2022).

H. Touhara, et al., Solid State Ionics, 14, 163 (1984).

J. Wang, J. Mater. Chem. A, 8, 6105 (2020).
Probing Transition Metal Dissolution/Redeposition Dynamics of NMC 900505
Authors: Meyer Katelyn Marie , Xia Dawei , Promi Anika Tabassum , Lin Feng
Published: December 2024

Transition metal (TM) dissolution from cathode active material into the electrolyte is a well-documented phenomenon occurring across a variety of cathode active materials. These TM complexes deposit on the anode, damaging the solid electrolyte interphase and leading to irreversible capacity loss. Recent work has demonstrated that these TM species may also redeposit onto the cathode and form part of the cathode electrolyte interphase (CEI). However, the dynamics of this redeposition and its driving forces have not been well studied due to characterization challenges. The goal of our work is to better understand TM dissolution/redeposition (D/R) dynamics in NMC cathode materials spatially and as a function of voltage. Using x-ray fluorescence microscopy, we visualize operando TM D/R dynamics on the surface of an NMC 900505 cathode in an organic electrolyte. Our results show that TM redeposition is spatially anisotropic and varies throughout cycling conditions. This work represents the first operando imaging of TM D/R dynamics of an NMC cathode and provides valuable insights for future work on engineering the CEI of nickel-rich NMCs.
Polyimide-Based Composite Separators for Super-Stable Li Metal-Based Batteries
Authors: Kim Patrick Joohyun , Choi Junghyun , Park Min Su , Woo Sujeong
Published: December 2024

Metallic lithium (Li) has garnered significant interest from battery industries and academia investigating next-generation anodes, due to its excellent properties: high specific capacity (3860 mAh g-1), the most negative potential (close to -3.04 V vs. SHE), and low density. Unfortunately, inherent challenges associated with inhomogeneous Li plating/stripping and poor Coulombic efficiency impede the pragmatic use of Li metal anode for conventional batteries. Moreover, thermal shrinkage of polyolefin separators presents a critical issue when Li metal batteries are subjected to high current levels, leading to an inability of the separators to shield the cell from short-circuits effectively.

The fabrication of polyimide-based composite separators via non-solvent-nduced phase separation (NIPS) is particularly promising for enhancing the electrochemical stability of Li metal batteries. A diversity of functional materials has been examined for the preparation of these composite separators, which have subsequently been assessed in Li metal battery systems. Beyond the development of composite structures, the surface modification of polyimide separators has also been explored to further optimize performance in Li metal batteries. Throughout this talk, we are going to give a talk about our research findings and strategic direction in detail. This presentation would assist many researchers in gaining insights into the design of new battery separators.
Data-Driven Design for Electrolyte Additives Supporting High-Performance Lithium-Ion Batteries
Authors: Liao Chen , Wang Bingning , Doan Hieu , Son Seoung-Bum , Abraham Daniel P. , Trask Stephen E. , Jansen Andrew N.
Published: December 2024

We presented here two cases of data-driven electrolyte additive design, using two cathodes as examples. In scenario 1, LiNi0.5Mn1.5O4 (LNMO), a spinel-structured material with an average lithiation/de-lithiation potential at ca. 4.6-4.7 V, was used as an example for the extreme high working potentials and the resultant strains on electrolytes. In this study, we first selected and tested a diverse collection of 28 single and dual additives for the LNMO//Gr system using descriptors representative of chemical functionality.(1) Subsequently, we trained and employed machine learning (ML) models to suggest 6 binary compositions out of 125 based on predicted final area specific impedance (ASI), impedance rise (ΔASI), and final specific capacity(Q). Notably, this approach led to the discovery of a new dual additive which outperforms the initial dataset.

In Scenario 2, the AI-guided workflow undergoes further enhancement for accelerated additive optimization employing new data featuring an earth-abundant cathode material of 0.3Li2MnO3·0.7LiMn0.5Ni0.5O2. This phase of the study introduces a more robust machine learning (ML) model for performance prediction, utilizing Figure of Merit Energy (FOME) and Figure of Merit Power (FOMP) as predictive metrics. Following three , Bayesian optimization iterations, 15 out of 78,000 binary and tertiary additive combinations was suggested for experiments, and several novel addtive compositions exhibiting unexpectedly high performance were subsequently identified. The optimal formulation surpasses the current standard by achieving a performance enhancement of 15-19%, as confirmed through experimental testing conducted in coin cells.

Overall, our findings not only underscores the efficacy of ML in identifying new additives combinations, but also introduces an accelerated material discovery workflow that directly integrates data-drive methods with battery testing experiments.

(1) ACS Omega 2018, 3, 7, 7868–7874
The Li-Ion Battery, the Electrification Revolution, and the Next Ideal Battery
Authors: Xu Kang , Hu Qichao
Published: December 2024

Following Whittingham’s first reversible intercalation electrode (1976) and Goodenough’s identification of oxides as more viable materials (1980), it took more than a decade for the modern lithium-ion batteries (LIBs) to be invented (Asahi Kansai 1986, Sony 1990 and Sanyo 1994). It would take another decade for someone to finally integrate these tiny LIBs into a car (AC Propulsion, 2000) and then verify their commercial viability in mass produced electric vehicles (Tesla, 2004).

Fast forwarding into 2020s, LIB is regarded a strategic technology of national security significance, driven by the compounded forces intertwined with geopolitical animosity, supply chain anxiety as well as climate change concern and responsibility for the environment and future generations. This new complicated scenario, starting about a decade ago but only becoming pronounced in the last 5 years, undoubtedly accelerated the penetration of LIB technology in every aspect of our life, from mobile to transportation to grid-storage, with new application scenarios such as Urban Air Mobility looming over the horizon.

Due to the thermodynamic limits imposed by the intercalation chemistry nature, LIBs cannot meet the expectations of most new applications. The call for a better battery chemistry is never so urgent, and we certainly do not have another four decades to develop such an ideal battery.

In this talk I will discuss the opportunities and challenges of designing the next generation batteries, and highlight the bold and ambitious initiatives of SES in addressing these challenges by leveraging the contemporary AI revolution to explore the large chemical universe.
The Solid Electrolyte Interphase Dispersion Can Predict Cycle and Calendar Lifetimes in Silicon Anodes for Lithium-Ion Batteries
Authors: Carroll Gerard Michael , Schulze Maxwell C. , Veith Gabriel M.
Published: December 2024

The solid electrolyte interphase (SEI) plays a critical role in lithium-ion battery (LIB) anodes. It is responsible for passivating the reactive surface of lithiated anodes against degradation of the electrolyte which enables long cycle and calendar lifetimes for LIBs. This role is especially important in high energy density anodes like silicon, that undergo massive volumetric changes during electrochemical cycling. The mechanism by which the SEI performs this role, however, is not clear which makes designing an SEI to passivate silicon anodes impossible. Through decades of research, dozens of chemical species have been identified within the SEI ranging from inorganic solids to polymeric coatings all of which simultaneously exist in a ‘mosaic’ composition at the anode surface. This mosaic creates a highly dispersive environment in which electrostatic screening of the anode surface from the electrolyte is not always complete. Here, we present an electrochemical technique to directly test the dispersion at the anode surface. We use this technique to screen more than 20 different electrolytes against silicon anodes and find correlations between both the cycle life and calendar life. The insights from this study offer a new framework to think about the SEI and a rapid screening method to test novel electrode/electrolyte combinations.
Dry-Deposited Self-Standing Composite Electrodes for EV Battery Applications
Authors: Kuznetsov Oleg A , Harutyunyan Avetik R.
Published: December 2024

Novel type of composite materials consisting of powdered materials embedded into a 3-dimensional network of pristine individual or a few-bundled single wall carbon nanotubes (SWNTs) has been developed [1]. A wide selection of powdered materials can be used, and SWNT content can be varied in a broad range. The resulted composite materials typically are self-standing, mechanically robust and with electrical conductivity 101-105 S/m, depending on the material composition and density. We have been using this technology to create composites of Li-ion battery materials for self-standing, binder and collector free battery electrodes. Application of these electrodes allows to increase battery energy density up to 40% and increase specific energy up to 70% in relatively small flexible pouch cells [1]. Since we can produce electrodes with very high thicknesses and high loadings of the active material, with minimal amount of electrochemically inactive components, we are studying applicability of such electrodes for large EV-sized batteries and for both high energy and high-power applications typical for EV/EVTOL batteries, and what parameters of the electrode material is necessary for such applications. Normally, EV batteries operate at 0.1C to 0.5C, to allow 10 to 2 hours of driving. However, they need to be able to operate at higher C-rates (2C to 10C typical) for short periods of time, when more power is needed for passing, hill climbing, etc. Battery performance for a particular battery chemistry depends on multiple interdependent parameters: electrode loading, electrode electronic conductivity, electrode density/porosity, electrode thickness, electrolyte ionic conductivity and many others. To achieve high energy density of a battery cell its electrodes are compressed as much as possible, and the amount of the electrolyte is minimized. However, this often leads to insufficient ionic conductivity of the electrodes, and, therefore, poor power performance (high C-rate performance). Parameters of electrodes of EV/EVTOL batteries need to be optimized for these applications. Here we concentrate on dependence of the high C-rate performance of the cells on the electrode density/porosity and electrode thickness with fixed cathode areal loading and conductivity (proportional to the CNT percentage). Cells with electrodes with the density in the 1.5-2 g/cm3 range demonstrate the best C-rate performance in the 3C to 30C range.

O.A. Kuznetsov, S. Mohanty, E. Pigos, G. Chen, W. Cai, A.R. Harutyunyan, High energy density flexible and ecofriendly lithium-ion smart battery. Energy Storage Materials, 2023 (54) 266-275, ISSN 2405-8297, doi.org/10.1016/j.ensm.2022.10.023
(Invited) Tracking Lithiation with Advanced Transmission Electron Microscopy
Authors: Su Dong
Published: December 2024

The primary advantages of Li ion batteries (LIBs) over traditional energy storage devices include high voltage, large capacity and stable cycling ability [1]. Despite their tremendous success in the market of portable devices and electric vehicles, people are developing next generation of batteries for large-scale energy storage or severe working environment, which demands LIBs with better cycling stability, safety and higher energy-density. Investigations on how Li ions transport through the components in a battery, such as anode, cathode, and electrolyte, would be helpful to understand the performances of LIBs, and therefore to realize reversible lithiation/delithiation during cycling.

Transmission electron microscopy (TEM) is an indispensable tool in probing real-space local structures at atomic resolution. Recently, advanced TEM techniques have been applied into tracking the transportation of lithium ions in battery materials [2]. Emerging methods like ABF, e-ABF, iDPC, EELS and ptychography offer possibilities to atomically observe Li ions' occupations, identify their chemical environment, and track the dynamics of their insertion and extraction [3-6]. At present, cryo-TEM technique is a hot spot to study the solid-electrolyte interphase where Li contained organic or inorganic compounds are very beam sensitive [7]. In-situ TEM techniques have unparallel merits to track the migration of lithium ions or see the phase transmission of electrode materials [8-9]. In this talk, we introduce the techniques for direct observation of Li species and their research advances in LIB materials. Perspectives for the current challenges and future development to investigate Li-containing materials are discussed.

References:

[1] A. Manthiram, et al., Nature Energy, 6 (2021) P.323.

[2] X. Lei, et al.,Science China Chemistry, (2023) https://doi.org/10.1007/s11426-022-1486-1

[3] L. Gu, et al.,Journal of the American Chemical Society, 133 (2011) p.4661.

[4] S. Li, et al., Angew. Chem. Int. Ed., 59 (2020) p.22092.

[5] S. Weng, et al., Carbon Energy, 5 (2023) p.e224.

[6] X. Lu, et al., Nano Letters, 12 (2012) p.6192.

[7] X. Wang, et al., Nano Letters, 17 (2017) p.7606.

[8] K. He, et al., Nature Communications, 7 (2016) p.11441.

[9] J. Li, et al., Nature Communications, 10 (2019) p.2224.

[10] This work is supported by National Key Research and Development Program of China Grant [No. 2020YFB2007400], the National Natural Science Foundation of China [No. 22075317], and the Strategic Priority Research Program (B) [No. XDB33030200] of Chinese Academy of Sciences.
NMR Studies of High Voltage Electrolyte Decomposition Reactions
Authors: Liu Haoyu , Ilic Stefan , Cabana Jordi , Strmcnik Dusan , Key Baris
Published: December 2024

Lithium-ion batteries have become an irreplaceable part of daily life, yet state-of-art LIBs could not meet the growing demand of higher energy density partially due to limited choices for the cathode and the electrolyte that can provide the desired safety and reliability. One of the solutions is to move towards higher voltage systems. To rationalize the CEI design, on the electrolyte side, fundamental studies of electrochemical decomposition behavior at high voltage of common electrolytes, typically using carbonate-based organic solvent, remain incomplete despite experimental and computational efforts. Several decomposition products of EC were identified, mostly pointing at ring-opened linear molecules such as CO, CO2, glycolic acid and oxalic acid with the presence of active/singlet oxygen or PEO-like polymer owing to Lewis acid induced polymerization. However, in some cases there were no ring opening observed with EC forming vinylene carbonate (VC) or poly-EC instead. While the mechanism of ring-opening reactions that involve deprotonation, nucleophilic and/or electrophilic reactions are straightforward and widely reported, full reaction mechanisms pathways are not yet realized. In this study we combined experimental and computational NMR to track the dynamic evolution of intermediate species to discover their chemical nature by following their NMR fingerprints. The findings will be presented to provide a clearer picture of the effects of high voltage on electrolyte systems in general and their implications on overall battery chemistry.
Fluorine-Free Binder-Based Dry Thick Electrodes Toward Sustainable and Efficient Libs
Authors: Kim Minkyung , Kim Jinsoo
Published: December 2024

Dry electrodes are rigorously developed for sustainable and efficient battery manufacturing. Currently, polytetrafluoroethylene (PTFE) binders dominate dry processes, yet their production contributes to significant CO2 emissions, and concerns persist regarding their high fluorine content, especially in light of evolving Per- and Polyfluorinated Substances (PFAS) restrictions. Moreover, the poor adhesion of bare current collectors necessitates a wet coating-based primer layer. In this study, we introduce an alternative dry processing concept based on a thermoplastic fluorine-free binder with low environmental impact and high productivity. Paraffin, a short-chain family of saturated hydrocarbons known as an n-alkane, is the most stable chemical species owing to its C-H covalent bonds and the wide gap between HOMO-LUMO energies. It also has a low melting temperature, allowing facile cohesion of the active materials to be interconnected by mild pressing activation. This new dry electrode binder provides substantial electrochemical properties based on both NCM cathodes and graphite anodes over 7 mAh cm−2. Furthermore, it implements true solvent-free adhesion without the wet-coating of primers on the current collector. This unique characteristic of paraffin enables a powder-to-electrode manufacturing strategy with pattern coating, which alters the well-known PTFE-based freestanding concept. This integrated approach bridges the gap between materials and processes, paving the way for sustainable advancements in battery electrode technology.