bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of Lattice Flexibility on Electrochemical Ion Insertion: Structural Dynamics in WO3 vs WO2.9
Authors: Musico Vincenzo , Holzapfel Noah , Tsai Wan-Yu , Balke Nina , Augustyn Veronica
Published: December 2024

The demand for high energy and high power energy storage devices drives the search for electrode materials that can exhibit high capacities and fast kinetics. One strategy to achieve these properties is through the use of ion insertion-type electrodes that can undergo at least 1 e- transfer (for high specific capacity) with little structural change (for fast kinetics). To investigate this strategy, we examined the ion insertion behavior of WO3 with the related oxygen deficient Magnéli phase, WO2.9. WO2.9 contains crystallographic shear planes, which are planes of edge-sharing WO6 octahedra within a corner-sharing framework. The presence of crystallographic shear planes is proposed to increase ion insertion kinetics because they decrease the lattice flexibility of the material.

To test this hypothesis, we performed cyclic voltammetry in aqueous and non-aqueous electrolytes as well as galvanostatic intermittent titration technique (GITT) and galvanostatic charge discharge (GCD) to study the kinetics H+ and Li+ insertion into WO3 and WO2.9. In acidic electrolytes, WO3 inserts more H+, achieving a capacity of 41 mAh/g, compared to WO2.9 which has a capacity of 17.5 mAh/g. In non-aqueous electrolytes, WO2.9 can insert more Li+ than WO3, achieving a capacity of 127 mAh/g at a rate of C/10 compared to WO3, which has a capacity of 100 mAh/g. During Li+ insertion, WO2.9 exhibits a diffusion coefficient of 10-8 cm2/s compared to WO3, which has a diffusion coefficient of 10-10 cm2/s. To measure the lattice flexibility during H+ insertion, we performed operando AFM experiments. We measured the local change in thickness of tungsten oxide electrodes in aqueous acidic electrolyte during electrochemical cycling. We observe that WO2.9 undergoes less deformation during proton insertion and de-insertion than WO3. However, it undergoes higher deformation per e-/formula unit. To investigate the lattice flexibility and structural changes during Li+ insertion and de-insertion, we performed in situ XRD and observed that WO2.9 undergoes a small volumetric contraction of < 0.6% during the insertion of 1.14 Li+ per formula unit. This study reports the benefits and tradeoffs of utilizing non-stoichiometric oxides like WO2.9 as electrodes for insertion-type high power energy storage.
High-Performance Na-Ion Battery Anode Using Graphene Oxide Quantum Dots
Authors: Boud Shahd , Seo Hyung Kee
Published: December 2024

Graphene Oxide Quantum Dots (GOQD) have shown remarkable potential in enhancing the performance of sodium-ion (Na-ion) battery anodes. This study explores the potential of GOQD as an anode material, leveraging its unique properties to enhance the performance of Na-ion batteries. GOQD are known for their exceptional electrical and optical properties, biocompatibility, and low toxicity, making them an ideal candidate for energy storage applications. Our research demonstrates that integrating GOQD into Na-ion battery anodes significantly improves their charge-discharge capabilities, stability, and cycle life. The small size and high surface area of GOQD contribute to an increased interaction with the sodium ions, facilitating faster ion transport and higher capacity. Additionally, the presence of GOQD in the anode material enhances the electrical conductivity, which is crucial for the rapid electron transfer necessary for high battery performance.
New Applications of Knudsen Effusion Mass Spectrometry (KEMS) for Gas Evolution Analysis in Lithium-Ion Batteries
Authors: Buch Jonas , Tahir Uzair , Markus Torsten , Henriques David
Published: December 2024

Kems4Bats, a new research group initiated under the BMBF's NanoMatFutur framework at Hochschule Mannheim, employs both established and innovative experimental methods to analyze thermal and gaseous emissions in lithium-ion batteries. Operating from a state-of-the-art laboratory equipped with advanced instrumentation, the group examines how variations in electrode materials and particle dimensions influence diffusion and gas generation. Key research focuses include studying diffusion processes, the formation of solid electrolyte interfaces, and the impacts of fast charging on battery aging. Significant achievements of Kems4Bats include the development of a new instrument based on the KEMS (Knudsen effusion mass spectrometry) method, which enables precise, real-time in-situ measurements of gas evolution in lithium-ion batteries. Moreover, this device allows for highly accurate measurements of vapor pressures, particularly for organic substances with high vapor pressures, such as electrolyte solvents. Additionally, the group has established a battery production line, enhancing the safety and effectiveness of these energy storage systems.

The improvement and detailed study of lithium-ion batteries are essential for advancing energy storage technologies. Understanding how gases evolve within these batteries during their formation, operational cycles, and aging is crucial for enhancing their performance and safety. Historically, Knudsen Effusion Mass Spectrometry (KEMS) has been an effective method for measuring the temperature-dependent vapor pressures of various materials, both organic and inorganic. This technique aids in calculating important thermodynamic properties. This study expands the application of KEMS to investigate gas evolution in lithium-ion batteries, marking a significant development in battery diagnostics.

A unique prototype was developed to modify the KEMS approach, allowing for accurate monitoring of gas species evolution in lithium-ion batteries. This innovation not only provides detailed insights into the types and quantities of gases produced at different stages of the battery lifecycle but also broadens the traditional boundaries of KEMS measurements. Our modified system allows for the analysis of substances with high vapor pressures, such as electrolyte components, which were previously challenging to study due to methodological limitations.

The results of this research shows the complex patterns of gas formation in lithium-ion batteries, providing essential insights for improving battery design and establishing higher safety standards. This research not only advances the field of battery technology but also highlights the adaptability of KEMS as a powerful tool in materials science.
Aligned Nano-Porous Electrospun Composite Electrolyte Based on Cellulose Acetate Casted with Chitosan for Flexible and Wearable Solid-State Sodium-Ion Batteries
Authors: Hassan Md. Mehadi , Conners Brett , Ebrahimian Mashhadi Mojtaba , Lu Qingye
Published: December 2024

The rapid advancement of modern wearable and smart microelectronics industries has led to a growing demand for cost-effective and sustainable flexible and wearable batteries. In this context, sodium-ion batteries (SIBs) emerge as a promising alternative to the prevailing lithium-ion batteries due to the higher abundance of sodium than lithium, their low cost, enhanced safety, and environmental friendliness. In this study, we introduce a nanoarchitecture strategy utilizing biodegradable, biocompatible, and naturally abundant materials—cellulose acetate (CA) and chitosan (CH) biopolymers—to fabricate nano-porous aligned electrospun composite electrolyte (AECE) for flexible and wearable solid-state SIBs. The aligned nano-porous electrospun morphology of CA fiber mats was tailored by adjusting key parameters such as the rotation speed of the collector, binary solvent system of dichloromethane and acetone, relative humidity, and the concentration of the CA feed solution. Subsequently, a straightforward solution casting step was carried out on the surface of the CA fiber mats using a solution of 1wt.% CH biopolymer and 10 wt.% NaPF6 salt to fabricate mechanically robust (12.34 MPa), thin-film (~76 µm), and flexible nano-porous AECE. The enhanced mechanical property of AECE was developed due to good compatibility of CH and CA biopolymers, as well as the binding property of positively charged CH with negatively charged CA. The microstructure of nano-porous aligned CA mats and optimized AECE were investigated through scanning electron microscopy (SEM) analysis. The room temperature (RT = 23°C) Na-ion conductivity (4.12 x 10-4 S/cm2) of nano-porous AECE demonstrated improved performance compared to that of non-porous AECE and randomly distributed nano-porous electrospun composite electrolytes because of the consistent Na+ transfer channels through highly porous and compact morphology of aligned electrospun CA fibers and the polymer matrix of CH. Uniform galvanostatic Na plating and stripping at RT is observed over 100 hours at 0.1 mA·cm-2 current density, indicating good electrochemical stability and compatibility with sodium metal. Further long-time RT Na plating-stripping and full-cell SIB performance with AECE are under investigation. Overall, as developed novel nano-architecture of porous aligned CA electrospun within the composite matrix facilitates smooth charge carrier activity, making it a promising candidate for flexible and wearable solid-state SIBs.

Keywords

Cellulose acetate, chitosan, aligned electrospun, sodium-ion battery, and Na plating-stripping.
MnO2-Conductive Nanodiamond Composite Electrode for High Energy Density Aqueous Capacitor
Authors: Imai Kazuto , Kondo Takeshi
Published: December 2024

Electric double-layer capacitors (EDLC) have the advantage of faster charge-discharge rates and superior cycle life compared to rechargeable batteries, but have the disadvantage of low energy density. In order to increase energy density of EDLCs, it is necessary to increase cell voltage and specific surface area. Another possible strategy to enhance the energy density is combination with redox-active compounds to form pseudocapacitor. We have developed boron-doped nanodiamond (BDND) as a novel electrode material for EDLC, which has a wide potential window in aqueous electrolytes, high voltage application capability, and large specific surface area. The aim of this study is to fabricate a pseudocapacitor by compositing BDND with MnO2 in order to further improve the energy density.

BDND was prepared by depositing a boron-doped diamond (BDD) layer on the surface of nanodiamond particles by microwave plasma CVD followed by heat treatment in air to minimize the sp2 carbon impurities. BDND ink was prepared by mixing BDND and ethanol. The BDND ink was then applied on a glassy carbon current collector, and MnO2-BDND electrodes were prepared by electrodeposition of MnO2 on the BDND using constant potential electrolysis in 0.6 M MnSO4/0.8 M H2SO4 at +1.25 V vs. Ag/AgCl. Cyclic voltammetry (CV) in 1 M Na2SO4 was used to evaluate the electrochemical properties of the MnO2-BDND electrode.

MnO2-BDND electrodes were prepared with various MnO2 deposition times of 1, 3, 5, and 15 min. It was found from the CV current density that the MnO2-BDND prepared at a deposition time of 3 min exhibited the largest capacitance of 43.5 F/g, while the capacitance of unmodified BDND electrode was 14.5 F/g. Therefore, MnO2 deposition time of 3 min was determined to be the optimum condition; the reason for the decrease in the CV current of MnO2-BDND with a deposition time of 5 and 15 min is considered to be due to excess amount of MnO2 with poor conductivity on the electrode surface. Energy density of the MnO2-BDND/1 M Na2SO4 system was calculated with a cell voltage of 1.5 V to be 21.2 Wh/kg, which was greater than that of the BDND/1 M Na2SO4 system (9.1 Wh/kg). Therefore, BDND-based high energy density aqueous capacitor is expected to be fabricated by the combination with MnO2.
Effect of Cell Diameter on Charge-Discharge Performance in All-Solid-State Batteries
Authors: Kamei Ayaka , Zhong Chengchao , Shimoda Keiji , Okazaki Ken-ichi , Orikasa Yuki
Published: December 2024

All-solid-state batteries are expected to offer high safety and energy density. The discovery of solid electrolytes with high ionic conductivity has accelerated development toward practical applications. However, high performance has only been demonstrated in small cells at the laboratory level and has not yet been introduced in larger all-solid-state batteries that can be used in electric vehicles and energy storage systems. To the best of our knowledge, no studies have been reported on all-solid-state batteries when large cells are used. To elucidate the factors required for large-scale all-solid-state batteries, we fabricated all-solid-state battery cells with various diameters and compared their charge-discharge performance.

Composite electrode was prepared by mixing the cathode active material Nb-coated LiNi1/3Mn1/3Co1/3O2, the solid electrolyte Li6PS5Cl, and the conductivity aid acetylene black in a weight ratio of 1:1:0.1 in an argon atmosphere. In-Li alloy was used for the counter electrode. Electrodes and electrolytes were placed in ceramic tubes with inner diameters of 10 and 30 mm with a fabrication pressure of 188 MPa and a stack pressure of 40 MPa. Galvanostatic charge-discharge measurements were performed between 2.0 and 4.0 V. AC impedance measurements were also carried out.

The initial discharge capacities of the cells with the diameters of 10 and 30 mm were both 140 mA h g-1 at a 0.1C rate. From the test of the rate capability, no clear difference was observed between the two cells. Nyquist plot from the AC impedance measurements exhibited one semicircle assigned to charge transfer resistance. The area specific resistance also did not show the difference in the cell diameter. These results imply that the size of the cell diameter does not affect the charge-discharge performance in cells capable of holding high pressures.
Controlling SnOx Stoichiometry via ALD Deposition on Cu Current Collectors: Investigating Stability and Reversibility Enhancement in Lithium Metal Batteries
Authors: Lee Dawon , Chung Roy Byungkyu
Published: December 2024

Recent advancements in battery technology have led to the emergence of various types of secondary batteries with higher capacities to meet increasing demands. Among these, research on Lithium metal batteries (LMBs) with high capacity potential is actively pursued. However, LMBs face stability issues due to dendrite formation and low reversibility in Li plating-stripping processes. To address these challenges, we have modified the surface of Cu current collectors with lithiatable material, SnOx, to inhibit dendrite formation, enhance the stability and reversibility of LMBs. Furthermore, SnOx films reduce the overpotential of Li and enable stable Solid Electrolyte Interphase (SEI) formation. Therefore, they enhance the reversibility of Li plating/stripping processes. SnOx films were deposited via Thermal Atomic Layer Deposition (ALD) at 200°C with a thickness of 20nm. We have already reported the effectiveness of SnOx in enhancing the efficiency and stability of LMBs.[1] Therefore, in this study, we conducted research on the variation in characteristics of LMBs resulting from the control of stoichiometry in this lithiatable SnOx. Stoichiometry was adjusted through two methods. One method involved post-deposition heat treatment, where treatments were conducted at 400°C for one hour under H2 (H2 4%, Ar 96% gas) and N2 atmospheres. Additionally, we adjusted the injection time of H2O, the reactant in ALD, varying it from 1 to 3sec to create an oxygen deficient environment, and analyzed each characteristic accordingly. We will present our findings on the effect of SnOx stoichiometry on the performance and stability of LMBs.

[1] Kim, Junghwan, et al. "Homogeneous Li Deposition guided by Ultra-thin Lithiophilic Layer for Highly Stable Anode-free Batteries." Energy Storage Materials (2023): 102899.

Figure 1
Electrochemical Capacitance and Synthetic Pore Modification in 2D Conductive Metal-Organic Framework
Authors: Lee Gyuwon , Park Sarah S.
Published: December 2024

Electrically conductive 2D metal-organic frameworks (MOFs) are a distinct class of materials known for their crystalline extended structures, porosity, and inherent electrical conductivity resulting from the in-plane conjugation system and out-of-plane π interaction, rendering them promising candidates for active electrode materials in electrochemical energy storage devices. Here, we investigated the charge storage mechanisms of a functionalized Cu-MOF, wherein the pore structure was tailored to enhance polarity. This synthetic modification induced a consequential alteration in its band structure, ultimately impacting its electrochemical performance. Through a comparative analysis with its isostructural parent MOF, our study aimed to elucidate the influence of pore modification on electrochemical capacitance. Our findings demonstrated an increased capacitance under aqueous condition compared to the parent MOF, primarily attributed to the facilitated diffusion of electrolyte ions into and within the MOF pores. While the utilization of 2D conductive MOFs holds promise for advancing energy storage technologies, offering versatile attributes including tunable structures, high surface area, and redox-active moieties, these results underscore the potential of systematic pore engineering to enhance electrochemical capacitance. Our study contributes to the ongoing investigation of electrode materials for supercapacitors, emphasizing the critical interplay between structure and function. We anticipate that our discoveries can stimulate further exploration in advanced materials for electrochemical energy storage applications and drive continued progress in the field of MOF-based electrode materials.
(General Student Poster Award Winner, 2nd Place) Understanding the Unique Phase Evolution of Prussian White Cathodes Mediated by the Intrainteraction in Hexacyanometallate Complexes
Authors: Lee Ju-Hyeon , Bae Jin-Gye , Kim Min Sung , Heo Jeong Yeon , Lee Hyeon Jeong , Lee Ji Hoon
Published: December 2024

Transition metal–based Prussian whites (TM-PWs), consisting of a cyanide anion ((–C≡N–)−) and TM cations in an alternative manner, have a general chemical formula of AxTMm+TMn+(CN)6. PWs are characterized by the TM electronic states that exclusively adopt low spin (LS) toward the C atom and high spin (HS) toward the N atom through the hybridized covalent bonding in the TM–C≡N–TM unit. This property would significantly affect the phase transition behavior upon the release and storage of carrier ions; however, there have been only few studies on their associated features.

In this talk, TM-PWs with different HS TM ions (Fe, Co, and Ni) were synthesized via co-precipitation and the phase transition behavior controlled by the π electron interaction between the cyanide anions and TM ions during battery operations was investigated. In situ X-ray diffraction and X-ray absorption fine structure analyses reveal that the combined effect of π bonding between metal and ligand effectively controls the bond length of the TM–C≡N–TM unit, thus influencing the lattice volume of TM-PW cathodes during the charge/discharge process. This study presents a comprehensive understanding of the structure–property relationship of the TM-PW cathodes involving π electron interactions during battery operations.
Compatibility of LiPON with Different Current Collector Materials for Anode-Free Configuration
Authors: Lopez Pazos Elena , Nobili Luca , Magagnin Luca
Published: December 2024

The current development of microelectronics requires mature micro energy storage devices. Such devices include, among others, micro batteries. The working principle of such micro batteries does not differ from traditional batteries. However, there are some particular aspects that distinguish them. The first one is that organic liquid electrolytes should be avoided due to their flammability and risk of leakage. Additionally, a great attention must be paid to the energy density of the included materials, since the final aim is the miniaturization [1]. In this sense, the use of thin film deposition techniques becomes crucial for micro batteries fabrication [2,3]. Among these techniques, sputtering constitutes an interesting choice, due to the possibility it offers to transfer the composition of a source target material to a substrate. As a result, thin compact layers with a well-controlled thickness can be obtained.

Regarding the solid-state electrolyte, LiPON is an interesting candidate due to the stability it reportedly offers for lithium plating-stripping [4]. A stable lithium cycle is fundamental for its use as metallic lithium anode or, taking a step further, for an anode-free configuration. Indeed, such king of configuration allows a great degree of device compactness, which is convenient when the miniaturization prosecuted [5].

This works aims at shed some light into the compatibility of LiPON thin films with different current collector materials. Sputtered LiPON thin films have been deposited in contact with different metals, and the produced samples have been characterised with electrochemical techniques such as Charge-Discharge, combined with materials characterization ones such as SEM. The obtained results have allowed to individuate how the plating-stripping of lithium is sustained by LiPON coupled with the different materials.

1]

L. Y. e. al, "On-Chip Batteries for Dust-Sized Computers," Advanced Energy Materials, vol. 12, p. 2103641, 2022.

[2]

B. J. Neudecker, N. J. Dudney and J. B. Bates, ""Lithium‐Free" Thin‐Film Battery with In Situ Plated Li Anode," J. Electrochem.
Soc., vol. 147, no. 517, 200.

[3]

T. Yamamoto, H. Iwasaki, Y. Suzuki, M. Sakakura, Y. Fujii, M. Motoyama and Y. Iriyama, "A Li-free inverted-stack all-solid-state thin film battery using crystalline cathode material," Electrochemistry Communications, vol. 105, 2019.

[4]

P. Albertus, S. Babinec, S. Litzelman, A. Newman, “Status and challenges in enabling the lithium metal electrode for high-energy and low-cost rechargeable batteries,” Nature Energy, pp 16-21, 2018

[5]

A.G.A.M.S. Nanda, “Anode-Free Full Cells: A pathway to High-Energy Density Lithium-Metal Batteries,” Advanced Energy Materials, vol. 11, 2021.
Functional Polyvinylidene Difluoride (PVDF) Separators for Next-Generation Lithium-Sulfur Batteries
Authors: McNaught Jillian W. , Petrecca Michael J. , Shenoy Akhil , Velev Orlin D. , Fedkiw Peter S.
Published: December 2024

The rising popularity of electric vehicles and the need for renewable energy storage (e.g., solar) have encouraged research into higher energy density and lower cost battery chemistries1. Li-S batteries possess high theoretical volumetric and gravimetric energy densities which may meet future energy demands. However, Li-S batteries have inherent barriers to sustained operation, including shuttling of soluble active material called polysulfide shuttling. This phenomenon results in rapid capacity face upon cycling due to irreversible parasitic reactions at the lithium electrode. Mitigation of polysulfide shuttling requires optimization of all cell components, including the separator, which is a key component of batteries that physically separates the anode and cathode while allowing the flow of ions between electrodes2. Herein we report a novel method of separator engineering that utilizes a multiphasic fabrication platform to create hierarchical membranes with tunable structures3. Poly(vinylidene difluoride) separators are fabricated via vacuum filtration from fibrous and nanosheet particulates. The particulates are also dispersed with SiO2 or Al2O3 to form polymer-ceramic composite separators. These separators show improved ionic conductivity (>1.5mS/cm) and thermal stability when compared to pure PVDF and Celgard separators at ambient temperature. The addition of ceramics also improves the polysulfide rejection capabilities of the membranes. Finally, full cell cycling demonstrates improved capacity retention when using the ceramic composite separators over other membrane formulations studied. Shear-driven nanofabrication is a potential means to produce ceramic-containing composite separators for future Li-S batteries.

1 Nazar, L. F., Cuisinier, M., & Pang, Q. (2014). Lithium-sulfur batteries. MRS Bulletin, 39(5), 436–442. https://doi.org/10.1557/mrs.2014.86

2 Robinson, J. B., Xi, K., Kumar, R. V., Ferrari, A. C., Au, H., Titirici, M., Parra-Puerto, A., Kucernak, A., Fitch, S. D. S., Garcı́a-Aráez, N., Brown, Z. L., Pasta, M., Furness, L., Kibler, A. J., Walsh, D. A., Johnson, L., Holc, C., Newton, G. N., Champness, N. R., . . . Shearing, P. R. (2021). 2021 roadmap on lithium sulfur batteries. JPhys Energy, 3(3), 031501. https://doi.org/10.1088/2515-7655/abdb9a

3 Luiso, S., Williams, A., Petrecca, M. J., Roh, S., Velev, O. D., & Fedkiw, P. S. (2021). Poly(Vinylidene difluoride) soft dendritic colloids as Li-Ion battery separators. Journal of the Electrochemical Society, 168(2), 020517. https://doi.org/10.1149/1945-7111/abdfa7
Nano-structured and High-performance Mn-based Positive Electrode Materials for Lithium-ion Batteries
Authors: Miyaoka Yuka , Ugata Yosuke , Oguro Yuna , Yabuuchi Naoaki
Published: December 2024

Towards widespread adoption of electric vehicles, Co/Ni-free and high energy density positive electrode materials for lithium-ion batteries are necessary. Among the various positive electrode materials, stoichiometric “zigzag”-type layered LiMnO2 with orthorhombic space-group symmetry has been extensively studied as potential high-energy and low-cost positive electrode materials. Although orthorhombic LiMnO2 delivers a large reversible capacity of over 200 mA h g-1 thorough a phase transition from layered to spinel-like phase during charging and discharging, over 30 cycles are required to obtain such a large reversible capacity due to the sluggish phase transition kinetics. In this study, nanostructured LiMnO2 with both orthorhombic and monoclinic layered domains is synthesized, and its electrochemical performance as positive electrode materials is examined. The nanostructured LiMnO2 delivers a maximum reversible capacity of >200 mA h g-1 within 5 cycles, indicating that the phase transition kinetics to the spinel-like phase upon electrochemical cycling are faster when compared with orthorhombic LiMnO2. Moreover, a significant improvement of cycle performance, i.e., ~90% retention after 100 cycles, is achieved by using a highly concentrated electrolyte solution coupled with lithium phosphate coating through suppression of Mn dissolution into electrolyte. From these results, the feasibility of practical Co/Ni-free high-energy positive electrode materials will be discussed in detail.
Factors Affecting Long-Term Cycle Stability of Cobalt-Free Li2MnO3-Based Materials
Authors: Motoki Chihaya , Ugata Yosuke , Handa Tokuhiko , Yabuuchi Naoaki
Published: December 2024

A layered-type solid solution material between Li2MnO3 and LiNi0.5Mn0.5O2, Li1.2Ni0.2Mn0.6O2, delivers a large reversible capacity over 220 mA h g–1, which exceeds the theoretical capacity calculated based on cationic redox of transition metal ions, through reversible anionic redox of oxide ions. However, a practical problem of this material is found in the poor electrode reversibility associated with partial oxygen loss during charging process. In this study, Li1.2Al0.04Ni0.18Mn0.58O2, where Ni and Mn ions are partially substituted with Al ions, is synthesized via a solid-state reaction under different synthesis conditions, and its electrochemical performance as a positive electrode material is examined. Li1.2Al0.04Ni0.18Mn0.58O2 samples are synthesized at various sintering temperatures ranging from 850 to 1100 oC, and single-phase samples are obtained except for 850 oC. Al3+ substitution effectively suppresses the capacity fading and voltage decay of Li1.2Ni0.2Mn0.6O2. In addition, Li1.2Al0.04Ni0.18Mn0.58O2 delivers a large reversible capacity of over 200 mA h g–1 through optimizing the specific surface area. Furthermore, the use of highly concentrated electrolytes with high oxidative stability and low solubility of Mn ions effectively improves electrode reversibility of Li1.2Al0.04Ni0.18Mn0.58O2. From these results, factors affecting the electrode properties of cobalt-free Li-rich layered oxides will be discussed in detail.
Simulative Analysis of Crucial Effective Transport Parameters of Li-Ion Cells Based on Experimental Voltage and Impedance Behavior
Authors: Mühlpfort Raphael , Pfeifer Leonie , Heß Anne , Wetzel Thomas , Seegert Philipp
Published: December 2024

The performance and aging behavior of a lithium-ion battery (LIB) are strongly influenced by inner processes as well as outer influence factors like the thermal boundary conditions.

A valuable and established tool to describe and gain a better understanding of the cell behavior is modelling using equivalent circuit models (ECM). For a deeper understanding and more detailed insights into the processes taking place inside the cell, physically based models, resolving the complex interaction of charge, heat and mass transfer as well as the electrochemical reaction by physical equations are needed. In this work, a model consisting of the combination of an equivalent circuit and a physical pseudo-2D (p2D) model according to Doyle-Fuller-Newman (DFN) was developed and implemented in COMSOL Multiphysics.

With the help of this model, impedance spectra and voltage behavior based on the multi-physical processes can be predicted and the underlaying parameters systematically analyzed. By comparison of the simulated cell behavior with experimental data, the physical parameters determining the overall cell behavior can be identified. This inverse-parameterization approach can be accelerated significantly by adding a least square gradient-based optimization tool, fitting the simulated behavior to an experimental data set by automatically optimizing the values of the physical parameters.

A challenging task by applying a DFN modeling approach combining with an optimization algorithm is to identify the value ranges of the crucial effective parameters, which are influenced by the microstructure of an electrode. An optimization of such a variety of parameters which interact strongly with each other may lead to a convenient fitting result but with underlying physical parameters which aren’t plausible. To take care of this issue this work focuses on both, voltage and impedance behavior of the cell as well on the investigation of the interaction of crucial parameters and their influence in the time and frequency domain. In addition, a 3D-microstructure model is used to narrow down the range of the effective transport parameters and to enhance the classical DFN and to complement in a target-oriented way.
(General Student Poster Award Winner, 1st Place) Synthesis and F-Ion Conduction of Ba0.57M0.43F2.43 (M = Y, La, Nd, Sm, Bi) As Solid Electrolytes for All-Solid-State F-Ion Batteries
Authors: Pattanathummasid Chanachai , Tani Kazuki , Matsunaga Toshiyuki , Takami Tsuyoshi
Published: December 2024

All-solid-state fluoride-ion batteries (FIBs) have attracted research attention because these batteries possess a high energy density surpassing the state-of-the-art Li-ion batteries.1 Yet, the lack of a fluoride-ion conductor with both highly ionic conductive and highly stable is one of the key bottlenecks in the development of FIBs. Conventionally, La0.9Ba0.1F2.9 (LBF) is used as a solid electrolyte in FIB. However, the cathodic stability of LBF limits the choice of anode materials unable to be below the reduction potential of LaF3/La as plating occurs. Our previous study showed that Ba4Bi3F17 (R−3) with a fluorite-like sublattice could form the disordered phase equivalent to a fluorite Ba0.57Bi0.43F2.43 (Fm−3m), enabling a fast fluoride-ion conduction comparable to LBF.2 By replacing Bi with the elements that have lower equilibrium fluorine activity, the electrolyte materials with higher stability could be anticipated. Therefore, in this study, mechanochemical synthesis was used to fabricate the disordered phases of Ba0.57M0.43F2.43 (M = Y, La, Nd, Sm, Bi) to study their electrochemical stability and F-ion conductivity.

The materials were synthesized using a mechanochemical technique with a planetary ball mill at 600 rpm for 12 h under a static argon atmosphere. The resultant phases were characterized using synchrotron X-ray diffraction (XRD) and time-of-flight neutron powder diffraction (NPD) to study the fluorine position and distribution in the structure. Impedance measurements were performed using blocking electrodes to estimate the electrical conductivity of the materials, and the electronic insulation of the materials was confirmed by DC polarization. Cyclic voltammetry was used to estimate the electrochemical stability window of the materials in comparison with LBF using Pt and Pb as a working electrode and a counter electrode, respectively.

Mechanochemical synthesis of the mixture of BaF2 and MF3 was shown to preserve the fluorite structure (Fm−3m) regarding the diffraction patterns. Electrochemical impedance spectroscopy showed the Nyquist plot of these materials as a semi-circle with a spike feature at low frequencies which is a typical response of ionic conduction under the blocking electrode scheme. The Arrhenius plot of the materials exhibited a slight difference in conductivity where the order of conductivity could be ranged from M = Bi > La > Nd > Sm > Y. The electrochemical stability window of the materials measured by cyclic voltammetry revealed that the stability of materials is in the order M = Y > Sm > LBF > Nd > La > Bi. The extraordinarily wide windows of M = Y and Sm exceeding that of LBF without a reduction peak open the possibility towards the use of high-energy anode materials, which will increase the energy density of the battery.
Dry-Processed Silicon-Graphite Composite Electrodes for Lithium-Ion Battery
Authors: Sheem JunMyoung , Kim Young-Jun
Published: December 2024

As the demand for increased energy density grows in the contemporary electric vehicle (EV) sector, lithium-ion batteries (LIBs) have emerged as the preferred choice within modern secondary battery technologies [1]. These batteries, owing to their remarkable characteristics, are valued for their outstanding energy density, enhanced specific energy efficiency, and high-performance metrics compared to alternative battery technologies [2]. With noticeable constraints becoming evident, endeavors are currently underway to discover effective solutions for commercial LIBs. These efforts primarily focus on advancing both cathode and anode electrodes to achieve high-energy density approaches. To attain this high energy density, the use of a dry-process technique is necessary. Dry processing offers several advantages over traditional solvent processes, particularly in terms of operational cost and energy efficiency, making it a promising alternative for electrode manufacturing in LIBs. Moreover, the absence of solvents allows to produce electrodes with higher mass loadings, potentially facilitating battery miniaturization. In this study, electrodes employing a solvent-free dry-process method were fabricated utilizing a blend of silicon and graphite as the anode material. Each step was meticulously optimized, particularly in the utilization of Polytetrafluoroethylene (PTFE) material, which is not typically used in electrode materials, resulting in significant advancements in alleviating potential issues. Building upon this, high-loading, high-density electrodes were successfully produced using the dry-process method. In this research, a current density of 6 mA/cm2 and an electrode density of 1.6 g/cc were successfully achieved using a dry process method. The manufactured electrode utilizes 20% silicon content to address the limitations of silicon oxide, achieving performance equal to or exceeding that of slurry state electrodes. These dry-process electrodes show potential to facilitate the development of lithium-ion batteries under harsh cell design conditions in the future.

Reference
s

[1] Nano Energy, 2017. 31: p. 113-143.

[2] Nature Chem
7, 19–29 (2015).
Revisiting the Low-Temperature “Stablization Process” for Starch-Derived Hard Carbon Anodes
Authors: Shen Yuke , Li Linsen , Ma Zi-Feng
Published: December 2024

Sodium-ion batteries are applicable in cost-sensitive fields like grid electricity storage systems due to the widely distributed of sodium reserves. Hard carbons currently stand out as the most promising anode for practical sodium-ion batteries, but their performance and economy require improvement. In this work, we successfully developed spherical hard carbons through controlled pyrolysis of starch. Starch has an attractive natural spherical morphology, but direct pyrolysis leads to the cracking of spherical structure caused by the rapid release of small molecules. To address this issue, we employed an additive-free "stablization process" to establish a stable structure prior to pyrolysis. The underlying principle of this "stablization process" has been clarified: preheating starch below its melting point prompts partial thermal decomposition, preventing structural meltdown during subsequent decomposition. The resulting hard carbon, obtained through controlled pyrolysis, exhibits a high tap density exceeding 1 g cm-3 and the optimal reversible capacity reaches 321 mAh g-1 with an outstanding initial columb efficiency of 88% at 30 mA g-1. Furthermore, its practical application was validated via multi–layer pouch cells. When coupled with Na2Fe(SO4)2
cathode, the pouch cell demonstrated a cycle life approaching 1000 cycles, surpassing all starch-based hard carbons reported thus far. This work guides an efficient approach for fabricating high–performance, remarkably economical hard carbon anodes for practical application of sodium-ion batteries.
Fibrous Porous Composite Interlayer Derived from Soft Dendritic Colloids for Lithium-Sulfur Batteries
Authors: Truong Tuyen T.T , Petrecca Michael J. , Leatherman Jaden R. , Velev Orlin D. , Fedkiw Peter S.
Published: December 2024

Lithium-sulfur (Li-S) batteries have emerged as a highly promising energy storage technology, owing to their high theoretical energy density and being based on abundant resources. However, they are challenged by the undesirable diffusion of soluble lithium polysulfides (LiPSs) towards the lithium metal anode in electrolytes during discharge/charge cycles, which is commonly known as the shuttle behavior of LiPSs. This phenomenon ultimately leads to the degradation of the long-term Li-S batteries stability and severely limits their practical applications. To overcome this challenge, we propose the development of an innovative composite intermediate interlayer (MWCNT/SDC-PVDF) aimed at reducing charge transfer resistance and effectively capturing dissolved polysulfides.

The novel polymer composite is synthesized using a recently introduced method to produce soft dendritic colloids (SDCs). The SDCs are generated through turbulent solvent-nonsolvent induced phase separation to precisely regulate the size and morphology of precipitated PVDF across varying length scales. The integration of multiple wall carbon nanotubes (MWCNT) and SDC-PVDF within a high-shear mixer enables the formation of a homogeneous composite mixture. The resulting matrix interlayer situated between the carbon nanotubes and the SDC-PVDF fibrillar polymer network exhibits a fibrous porous structure characterized by a substantial surface area higher than 103.04 m2g-1, effectively facilitating the entrapment and anchoring of LiPSs within this matrix. Furthermore, the porous framework also allows for re-utilising LiPSs in subsequent cycles to improve the irreversible of the Li-S cell.

The flexible fibrous and porous MWCNT/SDC-PVDF interlayer, featuring a thin layer (∼ 55 μm ) and high conductivity, serves to mitigate cell polarization. A Li-S cell with the interlayer demonstrates a notable initial reversible capacity of 1,100 mAh g-1 at 0.2 C. The cell also achieved good capacity retention of 65% after 300 cycles at 0.2 C and 81% retention at 0.1 C after 150 cycles.

Figure 1
Multimodal Analysis of Corrosion for AA6016 Alloy at the Boundaries between Aluminum Matrix/Intermetallic Particles
Authors: Hiraoka Yuki , Murase Yoshiharu , Katayama Hideki , Tsutsumi Yusuke , Kadowaki Mariko , Watanabe Hikari , Shitanda Isao , Itagaki Masayuki
Published: December 2024

Aluminum alloys are attracting attention as lightweight materials for automobiles, and the fact that intermetallic particles indispensable for improving strength of the alloys can be harmful to the corrosion resistance has become an issue. However, the initial corrosion behavior at the interface of intermetallic particles for aluminum alloys has been hardly examined using a comprehensive analysis method. In this study, a nano-micro scale multimodal analysis of Energy Dispersive X-ray Analysis (EDS), Electron Backscatter Diffraction (EBSD), and Kelvin Force Microscopy (KFM) was performed to clarify the initial corrosion behavior for AA6016.

AA6016 specimens (20 × 20 × 1 mm) were subjected to SEM-EDS/EBSD measurements after mirror polishing, followed by continuous KFM measurements after ion milling. The specimens were then immersed in 100 mL of 0.5 wt% NaCl solution for 1 hour at a corrosion test. The surfaces of the specimens were cleaned with distilled water, dried and subjected to subsequent KFM measurements. The measurement of SEM-EDS was conducted again after the series of KFM measurements prior and post corrosion test.

Fig. 1 shows SEM images of the typical specimen surface for AA6016 before corrosion tests. As shown in Fig. 1, two types of intermetallic particles: Al-Fe-Si and Mg-Si were identified by EDS measurements. The KFM measurements of the potential distribution on specimen surfaces confirmed that both intermetallic particles were noble in potential relative to the aluminum matrix. However, less significant difference in the potential was detected at the grain boundaries identified by the EBSD measurements. After the corrosion test, some trenches were formed at the boundaries of the Al-Fe-Si type particle, and the noble potential area expanded around the particle. As for the Mg-Si type particles, a dissolution of Mg was detected at the particle, and the noble potential region disappeared at the particles immediately after the corrosion test but reappeared with time. Furthermore, the formation of thick oxide films was implied after the corrosion test, especially at the boundaries of Al-Fe-Si type particle as well as at the Mg-Si type particle.

Thus, the initial corrosion behaviors of AA6016 related to the compositional/electrochemical modifications at and around intermetallic particles were demonstrated by using the nano-micro scale multimodal (EDS-EBSD-KFM) analysis. Although the modifications of compositions (Mg and O) as well as noble potential distribution were restricted within the particle for Mg-Si type particle, they were expanded at the boundaries and around the particle for Al-Fe-Si type particle. The Al-Fe-Si type intermetallic particles would play more important role than those of Mg-Si type particles in promoting localized corrosion for AA6016.

Figure 1
Predicting Salt Adsorption Capacity (SAC) and Membrane Fouling in Membrane Capacitive Deionization (MCDI) Using Machine Learning
Authors: Kwon Soomin , Park Sanghun
Published: December 2024

Capacitive deionization (CDI) is an electrochemical technology that utilizes porous carbon electrodes to remove ionic substances. Ions from the solution are adsorbed during the charging stage and the adsorbed ions are desorbed during the discharging process, repeating the process to operate the system. To enhance ion removal capacity and prolong life of systems compared to CDI, membrane capacitive deionization (MCDI) has been developed. MCDI includes both anion and cation exchange membranes to induce the co-ion expulsion effects during the discharging stage, thereby exhibiting superior ion adsorption capacity than CDI. However, the utilization of ion exchange membranes causes a new issue of membrane fouling. Natural organic matter (NOM) serves as a common precursor to membrane fouling in nature environment. Especially, NOM could lead to the formation of fouling layers that disrupt transport phenomena across membrane systems, including ion exchange membranes used in MCDI. Numerous modeling studies have been conducted to investigate the effect of fouling on MCDI, aiming to predict fouling and evaluate the performance of MCDI in advance. Although a mathematical model was developed to predict MCDI performance under natural organic matter conditions, it had limitations of achieving high accuracy in natural environments. While a modified mathematical model showed high accuracy in predicting adsorption time reduction and capacity, it demonstrated low accuracy at points where current was applied and varied. This highlights the limitations of the modified mathematical model, as it is inadequate to consider the actual operating environment of MCDI. Therefore, this study adopted a robust machine learning model to address the limitations of the mathematical models. Electrochemical profiles and feed water conditions were used as input parameter of the model, enabling the prediction of both salt adsorption capacity and the growth of fouling layer on ion exchange membranes during operation. Consequently, this approach could improve the prediction accuracy of MCDI performance while providing detailed insights into fouling layer development, facilitating efficient operation and management of the MCDI system.
Evaluation of the Applicability of Rotating Cylindrical Anodes for Higher Speed Copper Electrolytic Refining
Authors: Kaizuka Gen , Miyamoto Masayuki , Fukami Kazuhiro , Murase Kuniaki
Published: December 2024

With the aim of increasing the overall speed of conventional copper smelting, in which a dry process and an aqueous electrolysis are connected in series, the challenge is to increase the speed of the electrolysis by increasing the current density, since the electrolysis is the rate-determining step in the series. However, electrolysis at high current density causes passivation of the anode due to a significant increase in the copper ion concentration near the anode, which inhibits electrolysis.

The use of forced convection (stirring or jetting) has been considered to suppress passivation. However, it is not easy to apply the effect of forced convection uniformly across the electrode surface in the conventional electrolysis method, in which plate electrodes are arranged in a dense array.

In this study, we proposed a method to obtain forced convection by rotating the cylindrical electrode (anode) as shown in the figure. The diffusion of copper ions from the anode surface can be promoted efficiently and uniformly by using this method. As a first step in the evaluation of the applicability, we performed numerical simulations of the tertiary current distribution to investigated the effects of the cylindrical anode rotation on the correspondence between the current density and the copper ion concentration near the anode.

Figure 1
Recovery of Platinum Group Metals from Spent Catalysts By Hydrometallurgy and Electrodeposition Using Ionic Liquids
Authors: Mishima Takumi , Matsumiya Masahiko , Sasaki Yuji
Published: December 2024

The recovery of platinum group metals (PGMs) from automotive exhaust catalysts is very important. The phosphonium-based ionic liquid (IL) was applied to the separation and recovery of PGMs from leachate of spent catalysts. A hydrometallrgical process has been developed for the separation of Pt(IV) and Pd(II) from spent catalysts. This process consists of pre-treatment, leaching, continuous solvent extraction and potentiostatic electrodeposition. Pt(IV) and Pd(II) were extracted into the IL phase by anion exchange reaction. The separation factor of Pt/Pd, Pt/Rh and Pd/Rh was evaluated from the distribution ratio of each of the PGM elements. Continuous solvent extraction was used to prepare the enriched Pt(IV) and Pd(II) in the IL phase. The potentiostatic electrodeposition process was performed after a continuous solvent extraction step. Consequently, the electrodeposited Pt and Pd were found to be mostly in the metallic state, which was identified by means of SEM/EDX, XPS, and XRD.