bluuebunny/crossref_metadata_2025 huggingface dataset:
Stretchable Li Ion Battery Electrodes Using Ga-Based Liquid Metal and Ionic Liquids
Authors: Fujimoto Hikaru , Usami Natsuka , Kanto Moeka , Ota Hiroki , Watanabe Masayoshi , Ueno Kazuhide
Published: December 2024

Liquid metal has low melting point, high thermal and electronic conductivity, and fluidity. In addition to having above properties, eutectic gallium-indium (Ga-In) are characterized by low volatility and low toxicity compared to a typical liquid metal such as Hg1). Ionic liquids have attracted considerable attention owing to unique properties such as high ionic conductivity, low volatility, and thermal stability. In previous works, we reported ion gels, composed of polymer networks swollen with ionic liquid, as highly ion-conducting, self-standing and flexible gel electrolytes 2). In this study, to prepare a stretchable electrode having high electronic and ionic conductivity as well as high stretchability and flexibility, we combine liquid metal Ga-In and Li4Ti5O12 (LTO) with the ion gel. Ga-In is expected to function as a “deformable current collector” while LTO serves as the active material in a stretchable electrode. This composite stretchable electrode (metal gel electrode3)) has a potential to be used for stretchable Li ion batteries in wearable devices. To meet the requirements of stretchable batteries used in the wearable devices, we studied effects of ionic liquid and polymer structures on the electrochemical properties and stretchable properties of the prepared metal gel electrodes.

Acknowledgements

This study was supported in part by Core Research for Evolutionary Science and Technology (CREST) of the Japan Science and Technology Agency (JST).

References

1) N. Kazem, et al, Adv. Mater., 2017, 29, 1-14.

2) M. A. B. H. Susan, et al, J. Am. Chem. Soc., 2005, 127, 4976.

3) J. Asada, et al, Macromol. Chem. Phys., 2021, 223, 2100319.
Evaluation and Regulation of Interfacial Reaction of Cathode for Lithium-Sulfur Batteries to Improve Electrochemical Performance
Authors: Lee Seungmin , Hu Enyuan
Published: December 2024

In the pursuit of high-energy-density batteries, sulfur (S)-based materials have emerged as promising cathode materials due to high-capacity (1,672 mAh g-1 for lithium-sulfur) [1]. However, their degradation caused by the dissolution of reaction intermediates during electrochemical cycling, has led to diminished electrochemical performance. To address this issue, various surface treatments, including the formation of chemical/physical protective layers and doping with heteroatoms, have been explored [1-2]. Despite these efforts, real-time evaluation of the degradation and the effectiveness of such surface modifications on electrochemical performance remains challenging due to the difficulty in distinguishing between degradation and electrochemical reactions.

In this context, our aim is to evaluate the degradation of high-capacity S-based cathodes using electrochemical techniques in real-time. Specifically, we distinguish the chemical reactions from the electrochemical reactions based on the numerical analysis and further quantify the degradation. Furthermore, we apply our evaluation method to assess the effectiveness of surface treatments on electrode materials.

References

[1] S. Lee, K. Eom et al., Electrochimica Acta, 2022, 412, 140092

[2] S. Lee, K. Eom et al., Journal of Power Sources, 2023, 582, 233517
In Situ Formed Metal-p-n Heterojunction for Ultrahigh Energy Density Supercapattery: Decelerates Ion Diffusion to Sustain Slow Discharge
Authors: Selvaraj Seenivasan , T. Sivagurunathan Amarnath , Kim Do-Heyoung
Published: December 2024

Supercapatteries combine both diffusion-controlled and capacitive charge storage mechanisms to simultaneously deliver exceptional power density and energy density. Though developing materials that combine both charge storage mechanisms for use as supercapattery electrodes is difficult, one solution has been to modify a material that inherently has one of these mechanisms so that it also exhibits the other form of charge storage. In the present study, we modulate the electrochemical reconstruction of a W5N4 electrode to modify its charge storage from pure battery-type to pseudocapacitive. This modulation was carried out by embedding Co in W5N4 (Co-W5N4), leading to the formation of W-doped CoOOH as an active phase. The incorporation of a thin layer of TiO2 (Co-W5N4/TiO2) through atomic layer deposition minimized tungsten dissolution during reconstruction, thus generating in-situ a dynamic metal–p-n junction heterostructure (Co-W5N4||CoOOH||TiO2) that modulated the charge flow, achieving high-rate capability (retaining 53.1% at 50 A g−1 compared to 2 A g−1)and cyclic stability (82.8% after 100,000 cycles at a high current density of 40 A g−1). As illustrated by operando electrochemical impedance spectroscopy and physicochemical analysis, the dynamic response of metal–p-n junction sustains the pseudocapacitive charge storage mechanism at high current rate. This p-n junction modulated the diffusion speed of OH− ions due to a decrease and an increase in the width of the depletion layer under charging and discharging, respectively. The solid-state supercapattery device assembled with a positive CoWN/TiO2 electrode and a negative NiMo2S4/Fe2O3 electrode attained an impressive energy density of 259.5 Wh kg−
1 at a power density of 2550 W kg−
1 and operated in a stable manner over 25,000 cycles. Our study thus highlights the importance of the band structure and its dynamic response to the operating conditions, and our approach can be extended to the design of a variety of energy-storage electrodes and energy-conversion catalysts.
Accelerating the Electrochemical Formation of the δ Phase in Manganese-Rich Rocksalt Cathodes
Authors: Holstun Tucker , Mishra Tara , Huang Liliang , Yang Xiaochen , Ceder Gerbrand
Published: December 2024

Recently, advancements in Mn-based disordered rocksalt (DRX) cathodes have demonstrated not only high energy density but also an electrochemical transformation to a spinel-like phase, now referred to as the δ phase1,2,3. The δ phase possesses a unique domain structure, a flattened voltage profile and improved rate capability. However, two important challenges remain: the necessity to mill the material to reduce particle size after synthesis, and the prolonged cycling required to complete the transformation to spinel-like partial order. To address these challenges, we present the development of an electrochemical formation method that enables rapid and in-situ formation of this partially disordered spinel phase from a DRX cathode, including in micron-sized single crystals.

To gain a deeper understanding of this transformation process, we carry out a systematic study to determine whether the transformation to the δ phase can be accelerated through a precycling formation process. By employing this novel electrochemical approach to purposefully stimulate the transformation, we successfully reduce the time required from several weeks to as little as one day for Mn-rich DRX. Extended cycling and synchrotron X-ray diffraction confirm that these materials exhibit both equivalent performance and resulting structure to those obtained through conventional cycling over a much longer duration. Further characterization of this material using HAADF and 4-D STEM reveals the complex local structure of the spinel-like partial ordering. It is hoped that such a practical electrochemical formation method allows for an acceleration of research on these earth-abundant and energy-dense materials.

Li, L.; Lun, Z.; Chen, D.; Yue, Y.; Tong, W.; Chen, G.; Ceder, G.; Wang, C. Fluorination-Enhanced Surface Stability of Cation-Disordered Rocksalt Cathodes for Li-Ion Batteries. Adv Funct Mater 2021, 31 (25), 2101888. https://doi.org/10.1002/adfm.202101888.

Ahn, J.; Giovine, R.; Wu, V. C.; Koirala, K. P.; Wang, C.; Clément, R. J.; Chen, G. Ultrahigh-Capacity Rocksalt Cathodes Enabled by Cycling-Activated Structural Changes. Adv. Energy Mater. 2023. https://doi.org/10.1002/aenm.202300221.

Cai, Z.; Ouyang, B.; Hau, H.-M.; Chen, T.; Giovine, R.; Koirala, K. P.; Li, L.; Ji, H.; Ha, Y.; Sun, Y.; Huang, J.; Chen, Y.; Wu, V.; Yang, W.; Wang, C.; Clément, R. J.; Lun, Z.; Ceder, G. In Situ Formed Partially Disordered Phases as Earth-Abundant Mn-Rich Cathode Materials. Nat. Energy 2023, 1–10. https://doi.org/10.1038/s41560-023-01375-9.
Solubility-Enhanced Iron Complex Posolytes for Redox Flow Batteries
Authors: Okazawa Atsushi , Kakuchi Takayuki , Akahori Keisuke , Kawai Kosuke , Okubo Masashi
Published: December 2024

Redox flow batteries (RFBs) are promising stationary energy storage devices for renewables. Commercial RFBs possess potential disadvantages such as cost and resource constraint due to the use of vanadium. Therefore, organic compounds and metal coordination complexes have drawn much attention as redox active materials for RFB electrolytes. We focus on less expensive terpyridine iron complexes that have higher redox potential of approximately 1 V (vs. SHE) as an active material for both aqueous and non-aqueous RFB posolytes.[1] However, terpyridine iron complexes generally possess low solubility in nonaqueous and aqueous solvents. In this study, we improved the solubility of the complexes by multi-componentization based on asymmerizing molecular structures and using the diverse ion effect as shown in Figure 1, and then explored an application as active materials in posolytes.

Symmetric terpyridine-iron complexes, [Fe(R-tpy)2](PF6)2 (R-tpy: substituted terpyridine ligand), were synthesized by simple mixing with R-tpy ligands and an iron source in high yields of 96-98%. Cyclic voltammogram of a butoxy-substituted complex, [Fe(BuOtpy)2]2+ (1BuO), shows redox potentials of 0.57 V (vs Fc/Fc+) in CH3CN. The Fe2+/Fe3+ redox couple shifts to a higher potential compared to 0.72 V (vs Fc/Fc+) for the parent complex, [Fe(tpy)2]2+ (1H), because of the electron-donating substituent on the ligand. The solubility of 1BuO·(PF6)2 in CH3CN was estimated as 0.13 M by a UV-Vis method using a calibration curve, which is comparable to that of 1H·(PF6)2 (0.16 M). Such a low solubility of 1BuO·(PF6)2 is due to a stronger lattice energy derived from a tight packing between the iron complex cations and PF6
−. The mixing of 1H and 1BuO produced a mixture containing a new asymmetric complex [Fe(BuOtpy)(tpy)]2+. The solubility of the mixture increased to 0.49 M, which enhances a theoretical volumetric capacity of posolytes three times than those of the single-component ones (Figure 2). Further solubility improvement was achieved using complexes substituted with poly(ethylene glycol)-type chains.

Reference

[1] A. Okazawa, T. Kakuchi, M. Okubo, APL Mater.
11, 110901 (2023).

Figure 1
Coupling Electron Transfer Reactions of Quinones with Grotthuss Proton Transport of Concentrated Hydrogen-Bonded Electrolytes
Authors: Munoz Sanchez Miguel , Khokhar Vaishali , Savinell Robert F. , Gurkan Burcu E
Published: December 2024

Concentrated Hydrogen Bonded Electrolytes (CoHBEs) such as deep eutectic solvents and ionic liquids have been studied for redox flow batteries. The CoHBEs approach has advantages for large-scale energy storage in flow batteries due to its potentially high redox reactant solubility, large electrochemical stability window, low volatility, and the ability to be made of non-toxic and non-corrosive materials. However, they are often viscous and thus transport of ions and reactants are hindered. Protic Concentrated Hydrogen Bonded Electrolytes (P-CoHBEs) are structured electrolytes that facilitate ionic conductivity through Grotthuss type proton transport, and thus decoupling ionic conductivity from electrolyte viscosity. Imidazoles protonated with an acid is an example of a P-CoHBEs. Ideally, coupling a proton coupled electron transfer redox couple with a P-CoHBE will be useful for storing energy in a flow battery. In this research, we studied the charge transfer mechanism and kinetics of 9,10-anthraquinone (AQ) in a P-CoHBE composed of levulinic acid (LA) and 1H-Imidazole (Im) by electroanalytical techniques. The details of the experiments, the measurement results, and interpretation of data will be described in this presentation. The electrochemical behavior of AQ was found to be sensitive to the LA:Im composition where the hydrogen bonding and speciation were effectively varied, thus directly impacting the diffusivity of AQ. The La:Im composition also affected the proton-coupled electron transfer mechanism and under certain conditions the 2-electron transfer of AQ⇌AQ-⇌ AQ2- was observed to occur at a single potential at -0.91 V vs. Fc/Fc+. This suggests tunability of the hydrogen network for efficient and reversible PCET reactions based on P-CoHBEs’ component pKa values and Kamlet Taft parameters. By innovatively decoupling proton conductivity from viscosity through the potential exploitation of the Grotthuss mechanism, our research opens new avenues for enhancing ion transport efficiency in flow batteries and lays the groundwork for designing protic P-CoHBEs that optimize the hydrogen network for quick and reversible PCET reactions on quinones.
Investigation of Hydrogen Isotope Conductivity through Single- and Multi-Layer Graphene
Authors: Temme Robert , Abel Bernd
Published: December 2024

Since its discovery, the outstanding properties of graphene regarding electrical and thermal conductivity as well as mechanical stability have increased the interest of the scientific community in this versatile material. The intensive investigations on the material uncovered even more unique properties that were previously thought to be physically impossible. In 2014 Hu et al. had shown that pristine graphene, which was prior thought to be an impermeable barrier, could be penetrated by ions.[1] Especially ions of hydrogen isotopes seem to be able to penetrate graphene at a fast rate. This permeation is supposed to cause a separation where protium passes more easily than the other isotopes which is still thoroughly discussed in recent literature. Contrary to single layer graphene, the permeability through multiple layers of graphene as an A-B-stacking seems to be less discussed nor investigated. Theoretical calculations of Eren et al. proposed a possible and fast interstitial movement of ions through multi-layered 2D-materials.[2] Within this work we were able to prove that in fact, several layers of graphene could be penetrated by protons and deuterons. By utilizing impedance spectroscopy, it was possible to show that the ions pass through the graphene layers. The currents produced in this electrochemical ion pump exceeded 500 mA/cm2 and showed that the graphene added almost no additional resistance. Combining impedance spectroscopy with mass spectrometry, we were also able to analyze whether isotope separation occurred for protons and deuterons. With electrochemical measurements we validated conduction of ions through graphene but were unable to find any separation. Therefore, our results are challenging a lot of recent results in this field.

References:

[1]- Hu, S., Lozada-Hidalgo, M., Wang, F. et al. Proton transport through one-atom-thick crystals. Nature 516, 227–230 (2014). doi.org/10.1038/nature14015

[2]- Eren, Ismail, Yun An, and Agnieszka B. Kuc. "Hydrogen Transport Between Layers of Transition Metal‐Dichalcogenides." Advanced Materials Interfaces 11.4 (2024): doi.org/10.1002/-admi.202300798
(Invited) Synthesis and Interfacial Control of Electrode Architectures
Authors: Dai Sheng
Published: December 2024

Enhancements in electrochemical energy storage are rooted in the meticulous design of nanotextures achieved through the fabrication of electrode materials with precise compositions and structures. The intricate interplay between solvent and solute structures, along with dynamics at the charged interface, the transport of ions within pores, solvation/desolvation processes within pores nearing bare-ion dimensions, and the formation of interfaces through chemical reactions, all stand as pivotal parameters. This talk will delve into various synthesis methods tailored for energy storage, encompassing both inorganic and polymer electrodes. The aim is to illustrate how our synthesis strategies yield nanostructured polymers and oxides that not only boast high storage capacities but, more importantly, exhibit significantly enhanced electronic and ionic conductivities. These augmented transport properties within electrode architectures serve as the prerequisite for bestowing high-rate capabilities upon the corresponding energy storage systems.
Improving Corrosion Resistance By Anodizing of Aluminum Vapor-Deposited Magnesium
Authors: Araki Takuma , Tomita Shunsuke , Kikuchi Tatsuya
Published: December 2024

Magnesium can be widely available in various engineering applications, such as electronic components and vehicles, due to their light weight and high specific strength. However, magnesium easily corrodes in our environments, thus surface finishing is very important for improving corrosion resistance of magnesium. Although plasma electrolytic oxidation (PEO) is widely used for the corrosion protection of magnesium, this method requires higher voltages more than 200-300 V. In the present investigation, we describe a novel corrosion protection method of magnesium via vacuum vapor deposition of thin aluminum and subsequent anodizing.

Commercially available 99.95 wt% magnesium plates were electrochemically polished in a 0.5 M NaCl/diethylene glycol solution (308 K) at 75 V for 3 min. After electropolishing, a thin aluminum layer measuring up to 2 µm in thickness was coated onto the magnesium specimens by vacuum deposition. The aluminum-deposited magnesium specimens were anodized in a 0.3 M oxalic acid solution at a constant current of 30 Am-2 for up to 60 min to form anodic porous alumina. Finally, the anodized specimens were immersed in boiling water for 15 min to seal the pores. The surface and cross-section of the anodized specimens were examined by optical microscopy (OM) and scanning electron microscopy (SEM).

Figure 1 shows the voltage-time curves of the aluminum-deposited magnesium specimens during constant current anodizing in a 0.3 M oxalic acid solution at 30 Am-2. Here, the thickness of aluminum layer was adjusted to a) δ = 100 nm, b) 500 nm, c) 1 µm, and d) 2 µm. In the case of thinner aluminum thickness such as 100 nm and 500 nm, the voltages exhibit an almost steady value, and the dissolution of the bottom magnesium substrate was observed by SEM observations. This is due to the presence of microdefects reaching the magnesium substrate in the thin aluminum film. On the other hand, the voltages increase to approximately 30-35 V during anodizing using thick aluminum layer-deposited specimens, and an anodic porous alumina was formed. However, the voltage drastically decreased, and the magnesium substrate dissolved. Consequently, a corrosion-resistant porous alumina film could be successfully formed on the magnesium specimen by choosing the appropriate anodizing time.

Figure 1
High-Speed Manufacturing(<1 min) of Ultra-Thin Lithium Metal Anode for Safe and High-Energy Battery
Authors: Kim Jueun , Park Minjoon
Published: December 2024

Lithium metal batteries (LMB) are gaining attention as next-generation batteries due to their unique high energy density and high output. However, practical difficulties in the commercialization of lithium metal anodes (LMA) persist due to several inherent challenges. Conventional methods for manufacturing lithium metal anodes, such as the physical rolling of lithium metal onto copper foil, have limitations in achieving sufficiently thin lithium layers due to the resistivity of copper foil. LMA thicker than 30 μm lead to a high N/P ratio in batteries, resulting in lithium wastage and the formation of uneven solid electrolyte interphase (SEI) layers during cycling, which increase dead lithium and degrade battery performance.

As an alternative, we propose a strategy to drastically reduce the manufacturing time of lithium metal anodes while forming a stable interface. By applying optimized pressure tailored for the pouch cell used during lithium electroplating, we reduce the lithium-ion diffusion distance and ensure uniform contact between the lithium deposition target and the lithium source. Simultaneously, optimizing the temperature increases lithium ion mobility, mitigating concentration gradients within the cell during reactions and minimizing the imbalance of electric fields at the electrode surface. Consequently, electrodeposition occurs with low nucleation overpotential, forming stable lithium nuclei, and enabling smooth subsequent fast deposition reactions. We confirmed the feasibility of increasing the current density up to a maximum of 400 mA cm⁻², approximately 400 times higher than values reported in previous literature, with a deposition time of 36 seconds for the formation of 4 mAh cm⁻². Using this strategy, LMA deposited at 60 mA cm⁻² for 4 minutes, assembled with lithium iron phosphate (LFP), demonstrated stable cell performance over 170 cycles.

Furthermore, to enhance the cycling reversibility of lithium metal electrodes, we coated copper foil with lithiophilic Silicon Nitride (SN) layers. By depositing lithium on SN-coated Cu foil under controlled temperature and pressure, we observed reduced nucleation overpotential, dramatic increases in the size of lithium grain boundaries, and decreased porosity. Increased grain boundary size reduces contact with the electrolyte, thereby reducing side reactions and enhancing cell cycle stability. We performed coulombic efficiency (CE) tests to evaluate the reversibility of lithium on SN@Cu, demonstrating stable operation at 3 mA cm⁻² for 200 cycles. Additionally, symmetrical cell tests conducted at a current density of 1 mA cm⁻² and a capacity of 1 mAh cm⁻² exhibited further improved performance for over 400 cycles. Based on these two strategies, we anticipate practical applications in LMBs.

Figure 1
Oxidation of Ni Foil at 873K between Ar-1%O2 and Ar-5%H2 Gas Atmospheres
Authors: Kawamura Kenichi , Inoue Soichiro , Koinuma Yudai , Namba Ken
Published: December 2024

The thickness of the thermally grown oxide scale estimated from the diffusion coefficient is thinner than the experimental thickness. The reasons for this have been proposed to be the effects of grain boundaries, which are high-speed diffusion paths for oxide films, and the effects of cracks, but these have not yet been quantitatively addressed. In this study, we attempted to quantify physical defects such as cracks and pinholes in the oxide film.

One side of the Ni foil (100 μm thick) was oxidized with Ar-1%O2 and the other side was exposed with Ar-5%H2 at 873 K. At this time, the hydrogen that permeated through the Ni foil was converted into water and quantified using a dew point meter.

In single Ar-1%O2 atmosphere, the oxide film grew according to the parabolic law. On the other hand, when oxidizing one side with Ar-5%H2, not only the film growth was suppressed, but the scale thickness became almost constant after 500 ks. The amount of hydrogen permeation was almost unchanged depending on the presence or absence of the oxide film, indicating that the oxide scale contains physical defects that allow hydrogen to permeate.
Critical Roles of pH and Activated Carbon on the Speciation and Performance of an Archetypal Organometallic Complex for Aqueous Redox Flow Batteries
Authors: Holubowitch Nicolas , Burghoff Alexis
Published: December 2024

A lack of suitable high-potential catholytes (posolytes) hinders the development of aqueous redox flow batteries (RFBs) for large-scale energy storage. Hydrolysis of the charged (oxidized) catholyte typically occurs when its redox potential approaches that of water, with a negative impact on battery performance. Here we elucidate and address such behavior for a representative iron-based organometallic complex, showing that the associated voltage and capacity losses can be curtailed by several simple means.1 We discovered that addition of activated carbon cloth (ACC) to the reservoir of low-cost, high-potential [Fe(bpy)3]2+/3+ catholyte-limited aqueous redox flow batteries (Fig. 1) extends their lifetime and boosts discharge voltage – two typically orthogonal performance metrics. Similar effects are observed when the catholyte’s graphite felt electrode is electrochemically oxidized (overcharged) and by modifying the catholyte solution’s pH, which was monitored in situ for all flow batteries. Modulation of solution pH alters hydrolytic speciation of the charged catholyte from the typical dimeric species, µ-O-[FeIII(bpy)2(H2O)]2
4+, converting it to a higher-potential µ-dihydroxo form, µ-[FeIII(bpy)2(H2O)(OH)]2
4+, at lower pH. The existence of free bpyH2
2+ at low pH is found to strongly correlate with battery degradation. Near-neutral-pH RFBs employing a viologen anolyte, (SPr)2V, in excess with the [Fe(bpy)3]2+/3+ catholyte containing ACC exhibited high-voltage discharge for up to 600 cycles (41 days) with no discernible capacity fade. Correlating pH and voltage data offers powerful fundamental insight into organometallic (electro)chemistry with potential utility beyond battery applications. The findings, with implications toward a host of other “near-neutral” active species, illuminate the critical and underappreciated role of electrolyte pH on intracycle and long-term aqueous flow battery performance.

(1) Burghoff, A.; Holubowitch, N. E. Critical Roles of pH and Activated Carbon on the Speciation and Performance of an Archetypal Organometallic Complex for Aqueous Redox Flow Batteries. J. Am. Chem. Soc.
2024, 146 (14), 9728-9740. DOI: 10.1021/jacs.3c13828.

Figure 1. pH monitored in situ during long-term green catholyte experiment with ACC additions. (a) Schematic of pH probe experimental setup; (b) raw data for voltage and catholyte pH vs. time; (c) voltage and pH around the first ACC addition (80 mg at t = 37 h); (d) voltage and pH around the second ACC addition (80 mg at t = 64 h).

Figure 1
(Digital Presentation) Nanoscale Sculpturing of Al and Al Alloys for Heterogeneous Al-Cu Joints
Authors: Baytekin Gerngross Melike , Gerngross Mark Daniel , Carstensen Juergen , Adelung Rainer
Published: December 2024

Heterogeneous Al-Cu joints are nowadays generated in a huge variety of different techniques depending on the intended application, such as corrosion protection of Al components, electric connections with improved interfaces, or even lightweight current collectors for batteries.

Four major techniques are commonly used that can be further subdivided into cladding (including roll cladding, thermo-compression bonding, friction welding etc.), vapor deposition (including PVD, CVD etc.), thermal spraying and chemical plating (including electroless and electrochemical plating). Each of the methods offers certain advantages and disadvantages for the formation of Al-Cu joints. Typically observed disadvantages are the formation of intermetallic Al-Cu compounds (IMC), higher electric resistivity, a rather low mechanical strength under static or cyclic mechanical load conditions.

The present work follows the electrochemical route to form Al-Cu joints utilizing nanoscale sculpturing of the Al substrate [1] as a starting point to overcome these above described typically observed disadvantages of Al-Cu joints. The resulting nanoscale sculptured Al-Cu joint is intensively characterized with respect to its structural (see Fig. 1), chemical and mechanical properties. It was found that such Al-Cu joints offer a high mechanical load bearing capability because of the interlocking zone between Al and Cu offering a gradual change, so that an optimum stress transfer can occur without the risk of a stress pile-up at the interface between both metals.

Furthermore, no intermetallic Al-Cu phases grow at the interface between Al and Cu during deposition which could mechanically weaken the joint due to embrittlement, especially under cyclic loading conditions. Another advantage is the absence of Al-Cu intermetallics in the joint, being of great importance if high current or high voltage applications are intended.

Fig 1: Nanoscale sculptured Al surface with cubic interlocking surface structures in cross-section (left) and cross-sectional view on Al-Cu joint after electrochemical Cu deposition on nanoscale sculptured Al surface (right).

[1] M. Baytekin-Gerngross, M.D. Gerngross, J. Carstensen, and R. Adelung, Nanoscale Horizon 1(6), 467 (2016).

Figure 1
(Invited) One Dimensional Anodic TiO2 Nanotubes for Energy and Catalytic Applications
Authors: Sopha Hanna , Sepúlveda Sepúlveda Lina Marcela , Macak Jan M.
Published: December 2024

Self-organized TiO2 nanotube (TNT) layers, prepared by anodization of Ti have in suitable electrolytes, attracted considerable scientific and technological interest, especially due to their wide range of applications including (photo-) catalysis, hydrogen generation and biomedical uses [1,2].

The advantages of anodic TNT layers compared to TiO2 nanotubes prepared by other methods (e.g. hydrothermal) are the tunability of dimensions, their directionality, the ability to absorb significant amount of incident light, and the possibility to utilize nanotube interiors and exteriors for decoration or coating with secondary materials [2].

The presentation will review the recent advancements in TNT layer synthesis for their use for the photocatalytic degradation of pollutants in the liquid and in the gas phase. This will include the upscaling of TNT layers from the laboratory scale to several dozens of cm2 [3-6], with a strong focus on the anodization of 3D Ti substrates by bipolar electrochemistry, which cannot be directly connected to the potentiostat (such as Ti meshes) [5-6]. The application of these large scale TiO2 nanotube layers in flow-through photocatalytic reactors will be discussed [3-6]. Additionally, the selective etching of double wall TiO2 nanotube layers towards single wall TiO2 nanotube layers [7] and single nanotube powders [8, 9] will be presented, showing the possibility of preparing magnetically guidable single nanotube photocatalysts by a decoration with Fe3O4.

The presentation will also summarize recent advancements in the utilization of TNT layers in energy conversion and energy storage applications [10], in particular Li-ion microbatteries. Experimental details and photocatalytic and battery results will be presented and discussed.

References

[1] J.M. Macak et al., Curr. Opin. Solid State Mater., 11 (2007) 3.

[2] F. Dvorak et al., Appl. Mater. Today 14 (2019) 1-20.

[3] H. Sopha et al., Electrochem. Commun. 111 (2020) 106669.

[4] H. Sopha et al., Appl. Mater. Today, 29 (2022) 101567.

[5] H. Sopha, et al., Nano Lett. 21 (2021) 8701.

[6] H. Sopha, et al., Nano Lett. 23 (2023) 6406.

[7] M. Motola et al., Electrochem. Commun., 97 (2018) 97.

[8] D. Beketova et al., ACS Appl. Nano Mater. 3 (2020) 1553.

[9] M. Sepúlveda et al., Ceram. Int., 49 (2023) 6764.

[10] V. Galstyan, J.M. Macak, T. Djenizian, Appl. Mater. Today 29 (2022) 10161.
Open-Air Plasma Assisted Organosilicon Coating on AM60 Mg Alloy for Corrosion Protection
Authors: Jun Jiheon , Lim Yong-Chae , Su Yi-Feng , Pappas Daphne , Robinson Ryan
Published: December 2024

Mg alloy structural parts are of high interest to realize lightweight automobiles. However, corrosion susceptibility of Mg is one of the key technical challenges for the application of Mg alloys as vehicle parts. In this work, open-air plasma assisted organosilicon coating was deposited on AM60 Mg alloy as corrosion barrier using different deposition processes. This deposition process can minimize use of wet chemicals and be installed to existing industrial plasma devices. Corrosion evaluation of uncoated and organosilicon coated AM60 samples was conducted using electrochemical impedance spectroscopy, polarization and hydrogen collection measurements in 3.5% NaCl solution at room temperature. Post-immersion AM60 samples were characterized in comparison to unexposed AM60 samples using SEM, STEM and EDS to investigate progress of corrosion attack in uncoated and organosilicon coated surface conditions. According to corrosion evaluation, organosilicon coating provides corrosion protection for AM60 substrates in the initial stage. Long-term immersion results are currently under investigation.
(Invited) Atmospheric Corrosion of Multi-Materials on Winter Road Condition in Cold Region
Authors: Fushimi Koji , Nomura Kosaku , Sakairi Masatoshi
Published: December 2024

The use of multi-materials such as composites of carbon fiber reinforced thermoplastic (CFRTP) and high-strength steel or CFRTP and aluminum alloy is one of the main strategies for weight reduction in automotive body. When multi-materials are used outdoors, however, they are subject to galvanic corrosion, which increases the risk of failure and shortens their service life. On winter roads in cold regions, automotive bodies suffer significant corrosion due to the large amount of salt particles sprayed as an anti-freeze agent. If the corrosion products of the multi-material are relatively protective, the progression of corrosion can be prevented. Therefore, wet-and-dry cycle test was conducted on a coated multi-material joint consisting of CFRTP/high-strength steel or CFRTP/aluminum alloy plates to simulate winter road conditions in Northern Europe, and corrosion products formed in the crevice of multi-materials joint were investigated using a membrane potential measurement as well as Raman spectroscopy and X-ray fluorescence microscopy.

The wet-and-dry cycle test, in which a sample was immersed in a 5:1 mixture of NaCl and CaCl2 solutions for 0.25 h and then repeatedly subjected to a wet atmosphere of 90%RH, 283 K for 4 h and a dry atmosphere of 10%RH, 308 K for 4 h more than a dozen times, was performed according to Kozaki [1]. After several weeks or more of exposure under the wet-and-dry cycle test conditions, corrosion products filled the crevice of the multi-material sample and did not to allow air leakage through the crevice gap. Ion selectivity of the corrosion products in the crevice obtained by the membrane potential measurement was found to be anionic rather than cationic selective in all tests. The products formed in the test using dilute mixture solution were relatively porous hydroxides and oxides and showed larger fixed charge concentrations than those formed in the test using concentrated solution. It was suggested that the density and composition of corrosion products play important roles in preventing atmospheric, galvanic corrosion in the gap of CFRTP/high-strength steel or CFRTP/aluminum alloy joints.

[1] T. Kozaki, M. Umeta, J. Surf. Finish. Soc. Jpn.
73 (2022) 384-389.
Visualization of Hydrogen Absorbed into High Strength Steel during Corrosion Process By Mn Oxide Thin Film
Authors: Sugawara Yu , Omoda Masataka , Ootsuka Shinji
Published: December 2024

Hydrogen embrittlement is a serious problem for high strength steels because the susceptibility increases with the strength of steels. Reducing hydrogen absorption into steels is required for the prevention of hydrogen embrittlement. It is well-known that one of the hydrogen absorption processes for steels is atmospheric corrosion. In general, atmospheric corrosion causes a rough and non-uniform surface, thus hydrogen absorption into steels during the corrosion process is thought to have an uneven distribution. To observe the distribution of hydrogen absorption into steels, we reported a method for hydrogen mapping using a WO3 thin film1,2). As hydrogen enters, the WO3 film formed on the hydrogen-detection side changes color by the reaction from WO3 to HxWO3. In this study, the hydrogen mapping method was improved and became more responsive and visible using Mn oxide instead of WO3. In addition, we succeeded in visualizing the distribution of hydrogen absorption into the high strength steel during the corrosion process in 0.01 M NaCl using the hydrogen mapping method with Mn oxide. The hydrogen mapping test shows that the areas where the color of Mn oxide changed corresponded to the areas where corrosion products were deposited on the hydrogen-entry side. This result suggests that hydrogen absorption into the steel occurred at the corroded areas and did not occur preferentially at the cathodic reaction site.

1) Y. Sugawara, Y. Sakaizawa, A. Shibata, I. Muto, N. Hara, ISIJ Int., 58, 1860 (2018).

2) Y. Sugawara, H. Saito, ISIJ Int., 61, 1201 (2021).
Atmospheric Corrosion of Aluminum and Aluminum/Gold Thin Films
Authors: Stavila Vitalie , Sin-Yiu Carly , Heo Tae Wook , Merrill Laura C , Sugar Josh D , Melia Michael Anthony , Khan Ryan Muhammad , DelRio Frank William , Wood Brandon C. , Noell Philip James , Allendorf Mark D.
Published: December 2024

Aluminum and its alloys are extensively utilized in various applications due to their high thermal and electrical conductivity and inherent resistance to corrosion, primarily due to the formation of a protective oxide layer. However, the strength, durability and electrical properties of many aluminum-based materials and aluminum/gold contacts tend to diminish in humid environments. Therefore, a thorough understanding of the mechanistic aspects of atmospheric corrosion reactions over time in pure Al and galvanic Al/Au couples is crucial for predicting degradation and optimizing performance. Presently, much of our knowledge regarding atmospheric aluminum corrosion is derived from empirical correlations based on extensive corrosion data, typically involving a simplistic relationship between corrosion rates and environmental factors. However, the mechanistic understanding of corrosion processes, particularly during in the presence of electrolytes like sodium chloride found in the environment is not fully elucidated.

Here we propose a new surface approach to obtain mechanistic insights into atmospheric corrosion of Al and Al/Au thin films in the presence of NaCl. The corrosion rate is investigated through a combination of experimental and theoretical approaches, correlating corrosion kinetics with electrolyte chemistry, mass changes, and corrosion byproducts. Quartz crystal microbalance with dissipation (QCM-D) electrodes coated with aluminum and aluminum/gold contacts and sodium chloride serve as the experimental platform. The structure, composition, and surface morphology of the samples are analyzed using various techniques including grazing-incidence X-ray diffraction, FTIR spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy, transmission electron microscopy, and electron energy loss spectroscopy.

Operando data with nanogram resolution provided by the QCM-D technique allows real-time monitoring of corrosion product formation, facilitating the derivation of rate constants for corrosion surface reactions. It is observed that the reaction rate in dry air is negligible, but a significant acceleration occurs at relative air humidity levels of 50% and above. Additionally, this study delves into the impact of sodium chloride on the corrosion rate and reaction products, the influence of surface termination on aluminum oxide/hydroxide formation, and the temperature-dependent acceleration of electrochemical corrosion rates. Finally, by integrating theoretical insights with experimental findings, preliminary understanding of the rate-limiting steps has been achieved, paving the way for the development of validated computational models to simulate early-stage atmospheric corrosion processes.
Moving Next-Generation Phase-Field Models to BMS Applications - a Case Study That Confirms Professor Uzi Landau's Foresight
Authors: Telmasre Tushar , Concepcion Anthony , Kolluri Suryanarayana , Mishra Lubhani , Thiagarajan Raghav Sai , Matam Aditya Naveen , Subramaniam Akshay , Garrick Taylor R. , Subramanian Venkat R.
Published: December 2024

Physics-based electrochemical models play an important role in the model-based analysis, virtual engineering, estimation, control, and Battery Management Systems (BMS) of lithium-ion batteries.1 The diffusion process within the cell electrodes has typically been modeled using Fick's laws of diffusion.2 Recently, the intercalation of lithium ions in the electrode particle was posed as a phase change problem, where the area intercalated with lithium undergoes a phase change compared to the pristine material. Researchers have approached this phase change problem in terms of evolving core-shell problems3,4 and, more recently, using phase field models5,6 that may hold certain advantages over the traditional Fickian diffusion models. In this paper, we briefly discuss the relevance and rich physics of phase-field models and show how proper numerical analysis and schemes can help with implementing these models in BMS applications. Further, an investigation of phase-field model-based optimization framework predicts an impulse-like control profile and was designed to reduce capacity degradation. This work was partially inspired by the pulse-charging protocol proposed by Professor Landau in his 2006 work7. An open-source framework is developed and will be shared for predicting the (im)pulse protocol reported in this.

References:

Ramadesigan, V. et al. Modeling and simulation of lithium-ion batteries from a systems engineering perspective. J Electrochem Soc
159, R31–R45 (2012).

Doyle, M., Fuller, T. F. & Newman, J. Modeling of Galvanostatic Charge and Discharge of the Lithium/Polymer/Insertion Cell. J Electrochem Soc
140, 1526–1533 (1993).

Srinivasan, V. & Newman, J. Discharge Model for the Lithium Iron-Phosphate Electrode. J Electrochem Soc
151, A1517 (2004).

Dargaville, S. & Farrell, T. W. Predicting Active Material Utilization in LiFePO Electrodes Using a Multiscale Mathematical Model. J Electrochem Soc
157, A830 (2010).

Zeng, Y. & Bazant, M. Z. Phase Separation Dynamics in Isotropic Ion-Intercalation Particles. SIAM J Appl Math
74, 980–1004 (2014).

Singh, G. K., Ceder, G. & Bazant, M. Z. Intercalation dynamics in rechargeable battery materials: General theory and phase-transformation waves in LiFePO4. Electrochim Acta
53, 7599–7613 (2008).

Purushothaman, B. K. & Landau, U. Rapid Charging of Lithium-Ion Batteries Using Pulsed Currents. J Electrochem Soc
153, A533 (2006).

Figure 1
Revealing Failure Mechanisms in Zinc-Manganese Dioxide Batteries Via Nondestructive Electrochemical Diagnostics
Authors: Engmann Eugene , Atifi Abderrahman
Published: December 2024

The world of long-term-high-density energy storage systems is dominated by the lithium-ion (Li-ion) battery. However, associated setbacks with the Li ion industry such as safety, geopolitical concerns, and rising costs have spearheaded research into investigating alternative approaches to the Li-ion batteries. A promising alternative to the Li-ion battery is the zinc manganese oxide (Zn||MnO2) battery due to its high energy density and much safer chemistry. However, a step towards commercialization of the Zn||MnO2 requires a deep dive into the failure mechanisms native to such cells. These failure mechanisms are identified as electrolyte degradation, increased cell impedance, loss of Zn inventory, and loss of cathode inventory.

Conventionally, techniques employed in identifying failure mechanisms are destructive and time consuming. Thus, there is the need to investigate reliable nondestructive techniques which can predict failure mechanism in Zn|MnO2 cells. In this research an electrochemical approach is pursued, employing the use of cell features such as rest potentials and columbic efficiencies to model various failure mechanisms in Zn||EMD cells. Prior to investigating failure mechanisms, optimization of the Zn||EMD cell is explored based on particle size, EMD weight composition, and electrolyte volume to minimize Mn2+ dissolution.
Energy Storage Capability of Seawater Batteries for Intermittent Power Generation Systems: Conceptualization and Modeling
Authors: Park Sanghun , Son Moon
Published: December 2024

The utilization of renewable energy sources for electricity generation has seen a notable rise owing to the global push for sustainable practices. Nevertheless, the surplus electricity supplied beyond demand poses a significant global challenge due to the disparity between energy generation and consumption. To address this issue effectively, the storage of excess renewable energy in energy storage systems (ESSs) is crucial. This study introduces the concept of a seawater battery (SWB) as an ESS tailored for intermittent power sources and evaluates its energy storage capacity. Four charging scenarios mimicking various renewable energies - namely constant current, solar, tidal, and wind - were subjected to electrochemical testing. The energy efficiency rankings were as follows: solar power (80.4%) > tidal power (79.6%) > wind power (79.4%), showcasing the SWB's capability for storing intermittent renewable energy with reasonable efficiency compared to the ideal constant current charging condition (83.6%). Additionally, artificial intelligence models were developed to estimate the potential of SWBs, with long short-term memory models outperforming artificial neural network models. These models exhibited high precision (R2 > 0.99) and an extremely low error rate (< 0.18%) in predicting SWB potential. The conceptualization and modeling of SWBs as ESSs presented in this study could significantly contribute to the storage and management of intermittent energy sources.
Carbon-Based Perovskite Solar Cells: Interface Engineering of 5-AVAI Additive
Authors: Perrin Lara , Ito Seigo , Tsuji Ryuki , Flandin Lionel , Planes Emilie
Published: December 2024

Perovskite materials have great potential for high efficiencies in photovoltaic devices, with the best performances exceeding 26% in a single junction. We now need to further develop perovskite device architectures that combine ease of industrial development with effective durability. Among the alternatives, mesoporous frameworks based on metal oxide and carbon are promising due to their inherent high stability. In the presented work, two perovskite formulations will be compared: MAPbI3 and (5-AVA)xMA1-xPbI3. Both were infiltrated using drop casting as a final step, which provides a clean industrial process for large scale and stable perovskite devices. The aim was to highlight the differences in behavior between devices based on the traditional MAPbI3 perovskite when fabricated with or without 5-ammonium valeric acid iodide (5-AVAI) as an additive. A detailed study with a large series of characterizations (macroscopic functional properties, LBIC imaging, photoluminescence, UV-visible spectroscopy, X-ray diffraction, impedance spectroscopy) has provided new insights into how carbon-based mesoscopic perovskite solar cells perform and degrade.

Perovskites based on AVAI possess higher performances and durability than the original perovskite formulation, however they also demonstrated a higher potential for species diffusion and interface contamination. A special attention will be thus given to the method used to measure performances by analyzing J-V curves at different scan rates. Indeed, this allowed us to define boundary conditions allowing the observation of two different states within our devices (defined as ‘stable’ and ‘metastable’). This behavior was interpreted as a structural transition [1] and can vary according to the perovskite formulation. In addition, the degradation of performance with aging time under damp-heat conditions was found related to a different mechanism in devices formulated with or without AVAI: the critical damage occurring either at the perovskite interfaces or within the perovskite itself.

References:

[1] De Moor, G.; Charvin, N.; Farha, C.; Meyer, T.; Perrin, L.; Planes, E.; Flandin, L. Understanding the Anomalous J–V Curves in Carbon-Based Perovskite Solar Cells as a Structural Transition Induced by Ion Diffusion. Solar RRL
2024, 2300998.