bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding the Kinetic Origins of Voltage Relaxation and Low-Frequency EIS Measurements in Porous Electrodes
Authors: Kapate Nidhi , Kang Stephen D. , Kuo Jimmy J. , Zhao Hongbo , Chueh William C.
Published: December 2024

Overpotentials in porous electrodes lead to undesirable behavior during battery cycling and understanding the origins of these overpotentials is crucial. In Li-ion batteries, a significant fraction of the electrode overpotentials in layered cathodes like NMC's arise from low-frequency sources. These low-frequency overpotential sources and the impedances they lead to are traditionally analyzed in the time domain using galvanostatic intermittent titration technique (GITT) or the frequency domain using electrochemical impedance spectroscopy (EIS). Currently in the standard porous electrode model, solid-state diffusion of Li in the cathode material is the only mechanism that is considered to lead to the electrochemical behavior seen at low frequencies and longer timescales. However, there are various experimental inconsistencies that emerge when attributing voltage relaxation behavior and low-frequency impedance behavior solely to solid-state Li diffusion. Thus, it is necessary to further investigate and understand the true nature of the impedances that arise in these timescale and frequency regimes.

In this work, we investigate the origins of the voltage relaxation behavior and low-frequency impedance in porous electrodes. Using a 3-electrode coin cell system, we vary the kinetics of the electrode/electrolyte interface by systematically changing the salt concentration of the electrolyte used. We perform GITT and EIS measurements and find that the relaxation behavior and low-frequency impedance changes as the kinetics of the electrode/electrolyte interface changes. These results contradict the experimental dependencies that are expected to arise from a system that is only diffusion controlled. Instead of a solid-state diffusion limitation, we propose an alternative mechanism that could also contribute to the observed GITT and EIS behavior: a distribution of reaction constants. We demonstrate the validity of this hypothesis with a multi-particle simulation. Furthermore, we characterize the hierarchical morphology of porous electrodes through particle physisorption and nano-computed tomography and investigate how their complex structures could lead to inherently broad distributions of electrochemical reaction times.

Figure 1
(Battery Division Postdoctoral Associate Research Award Sponsored by MTI Corporation and the Jiang Family Foundation) Advancements and Challenges of Wide Temperature Electrolytes for Next-Generation Lithium Batteries
Authors: Xu Jijian , Borodin Oleg , Wang Chunsheng
Published: December 2024

High-energy lithium batteries are highly desired for next-generation electric vehicles, electric aviation, and renewable energy storage. Rational electrolyte design and regulated interfacial chemistry are crucial for high-energy batteries to enhance electrochemical performance. This talk will focus on electrolyte design for lithium batteries over wide-temperature operation. Understanding the limiting factors of wide temperature operation is crucial for exploiting its potential to advance rechargeable lithium batteries, yet it poses substantial challenges. Jijian will provide an in-depth analysis of interplays between solvation chemistry and interfacial reactions, dissect the failure mechanism of lithium batteries in extreme temperatures, and advocate for innovative strategies in electrolyte design and interphase engineering to enhance electrochemical performance across a wide temperature range.
Transition Metal Dissolution: Impacts on Cell Performance and Mitigation by Electrolyte Formulation
Authors: Guillot Sarah Lucienne , Usrey Monica Lee , Kerber Brian M , Du Peng , Zhou Liu (Amy) , Sriramulu Suresh
Published: December 2024

Layered lithium transition metal oxides with nickel, cobalt, and/or manganese are nearly ubiquitous as cathodes in lithium-ion batteries for high energy density applications. As the cells age through cycling or exposure to high temperatures, degradation mechanisms within the battery can lead to release of transition metals from the cathode lattice. The dissolution of transition metals from the cathode and deposition on the anode have been linked to increased capacity fade and poor coulombic efficiency, attributed to constant degradation of electrolyte at the anode interface and lithium inventory loss.1

Orbia’s Battery Materials Innovation Center (formerly known as Silatronix) specializes in the design, synthesis, formulation, and optimization of electrolyte components for specific applications, as well as electrolyte performance cell testing and cell post-mortem analyses. In this study, we explored modification of the electrolyte composition as a method to reduce transition metal dissolution in Gr/NMC811 multi-layer pouch cells. Battery tests under a variety of aging conditions such as high temperature cycling, low temperature cycling, calendar life, and high-rate tests were studied to understand the conditions that lead to transition metal dissolution, which was quantified by ICP-OES. The relationships between transition metal dissolution and cell performance were investigated, including correlations between capacity fade, cell impedance, voltage hysteresis, and lithium plating. Next, a wide range of electrolyte formulations were tested under the above aging conditions and the effects of electrolyte composition were assessed, including the selection and concentration of solvents, additives, and salts, on transition metal dissolution and performance impacts. Electrolyte components that consistently reduce manganese dissolution and improve cell performance under a wide range of conditions were identified and are discussed in this presentation. These results provide insights into the practical design of electrolytes for reducing transition metal dissolution in a manner that is specifically correlated with performance improvements.
Understanding Temperature Effects in Silicon-Containing Lithium-Ion Batteries
Authors: Bae Ji-Youn , Yu Seung-Ho
Published: December 2024

Silicon holds promise as a material for high-energy-density lithium-ion batteries (LIBs). Although graphite, commonly used in commercial LIBs, has excellent cycling stability, its energy density is limited by a specific capacity of only 372 mAh g-1. To address this limitation, silicon has garnered attention with its high specific capacity of 3,579 mAh g-1 and low operating voltage. Despite its advantages, silicon faces challenges such as significant volume changes during cycling and poor cyclability performance. One solution is to incorporate silicon into a graphite anode. However, many issues with silicon remain unresolved, particularly regarding cycle performance and aging under various temperature.

In this study, we investigate the effects of temperature on the phenomenon occurring in silicon/graphite composite anodes. Increasing the operating temperature significantly alters the cell performance. As temperature rises, not only does cycle performance deteriorate, but degradation due to self-discharge also intensifies. We observed differences in color change and open circuit voltage (OCV) of the composite anode due to the degradation using operando optical microscopy. Furthermore, we conducted energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) analysis of the solid electrolyte interphase (SEI) component, confirming variations in composition and ratio depending on temperature. Additionally, we examined differences in degradation tendency at high temperatures based on the graphite-to-silicon ratio in the anode and the type of electrolyte additive.

A deeper understanding of the phenomena in graphite/silicon composite electrodes will aid in extending the lifespan of silicon-containing LIBs under real operating conditions.

Figure 1. Cycle performance of graphite/Si full cell cycled at high temperature with 1.0 M LiPF6 in EC/EMC with various additives

Figure 1
Designing Polymeric Protective Layer Incorporating Functional Additives and Nanofillers for Lithium Metal Batteries
Authors: Kim Heesu , Kim Ji-Wan , Oh Myungkeun , Lee Dong-Hyun , Seo Samuel , Kim Dong-Won
Published: December 2024

As the demand for electric vehicles has increased, high-performance batteries with higher energy density are needed. In this respect, lithium metal has been a fascinating anode material for next-generation batteries due to its high energy specific capacity and low reduction potential enabling high energy density. However, the practical application of Li metal anode is still hindered because of lithium dendrite growth and the chemical instability between Li metal and electrolyte. Continuous side reaction during repetitive Li deposition/stripping process and dendritic growth of Li metal lead to cracks of solid electrolyte interface (SEI) and formation of massive dead Li, which causes consumption of electrolyte and rapid capacity fading. Various studies have been extensively investigated to modify the physicochemical properties of Li metal anode surface. Among them, a protective artificial SEI layer containing functional additives can be a promising solution. This layer can be used as an additive reservoir that supplies an extra amount of additive and constructs inorganic-based SEI on Li metal surface. Furthermore, introducing nanofillers to the artificial SEI layer enables to achieve uniform Li-ion distribution and mechanical robustness. In this study, we developed a protective artificial SEI layer containing an excessive amount of additives and nanofiller. It enabled to rapid construction of robust and inorganic-rich SEI layers during initial cycles. In addition, the addition of nanofillers in the polymer layer facilitated uniform Li deposition and high mechanical stability. Electrochemical properties were investigated by linear sweep voltammetry, cyclic voltammetry and Li/Li symmetric cells. XPS and ion chromatography were conducted to analyze the releasing and working mechanism of additives on Li anode. The cycling performance of cells employing 20 um-thick Li metal anode with a protective layer and high nickel NCM cathode was evaluated and will be reported.
3D Lithium-Metal Anode for High-Energy Lithium-Metal Batteries
Authors: Kim Kookhan , Eom Ji-Yong , Kim Jongmin , Kim Yang Soo
Published: December 2024

Lithium metal is often regarded as the ultimate anode for lithium-ion batteries (LIBs) due to its superior specific capacity (3,860 mAh g-1) and density (0.534 g cm-3). However, the real-world application of Li-metal electrodes is presently hindered by unregulated Li-plating and stripping, leading to unwanted dendritic growth and significant volume change during cycles. To overcome these challenges, we suggest a three-dimensional (3D) Li-metal anode, which incorporates 3D Ni foam as a current collector through a molten Li impregnation process. Our theoretical simulations and experimental results show that this 3D Li-metal electrode establishes an extensive contact area between the active Li metal and the current collector. This is advantageous in enhancing the reversibility by lowering the overpotential for Li-plating and stripping and suppressing the dendritic growth of Li during charge/discharge cycles. Moreover, the 3D Ni foam framework effectively mitigates dimensional change of the Li-metal electrode. For practical applications, we evaluate the viability of the 3D Li-metal electrode in a full-cell in comparison to a traditional 2D Li-metal electrode. We anticipate that our findings will contribute to the development of advanced Li-metal batteries.
Tailoring Particle Size/Morphology for the Stable Cathode Performance of Polygonal-Shaped Li(Ni,Mn)2O4 Single Crystals
Authors: Kim Minseuk , Ji Seulki , Lee Ho Jin , Lee Sun Sook , Song Young-Chul , Kim Yongseon , Choi Sungho
Published: December 2024

We regulate the particle size and surface facet of single-crystal (SC) Li(Ni,Mn)2O4 cathode materials to give guidance without compromising electrochemical performance. Adjusting the molten salt method with selecting sintering aids , we synthesized size controlled SC particles, both small and large, and evaluated their electrochemical characteristics focusing on differences in the lithiation/delithiation reactivity depending on size with crystal facet conditions. While the initial charge capacity is similar to each other, the given cathode using an small SC particle with ordered crystalline and uniform particle sizes (≤5 um) exhibits outstanding rate capability with stable capacity retention irrespective of loading density and current density, which indicates the stable lithium transport during the repetitive electrochemical reactions. The dependency of the impedance response with change in the electrode resistances as well as the stability during the cycle reactions in conjunction with the post-mortem the Li distribution by using laser-induced breakdown spectroscopy as function of porosity change and cell degradation are thoroughly discussed from the standpoint of regulated particle property.
Investigation of the Passivation Reaction of Li Metal in Liquid Electrolytes Using Microcalorimetry
Authors: Berg Sascha , Fonck Ferdinand , Figgemeier Egbert
Published: December 2024

The demand for energy storages with high energy density and long lifetime is growing rapidly. Using lithium metal as an anode would maximize the energy density of lithium batteries by having an anode-free system in the discharged state. Lithium-ion batteries can undergo several thousand cycles using liquid electrolytes with low capacity losses and very low safety risks. Passivation of lithium metal and the uncontrolled formation of lithium dendrites has so far prevented the large-scale commercialization of lithium-metal batteries with liquid electrolytes. Understanding the passivation reactions and formation of the solid electrolyte interphase in of lithium metal in liquid electrolytes is crucial to increase the longevity and safety of this system. In this study, we present experimental results on the lithium metal liquid interfaces for next-generation lithium batteries utilizing isothermal microcalorimetry.

The experimental setup involved the investigation of coin cells at a symmetrical lithium metal cell and lithium-copper (Li-Cu) half-cell level. Two baseline electrolytes were employed, including a carbonate (EC:EMC 3:7 wt%, 1M LiPF6) and an ether-based- formulation (LiFSI:DME:TTE 1:1.2:3 molar), supplemented with fluoroethylene carbonate (FEC) and vinylene carbonate (VC) additives. Those coin cells were investigated at various current densities ranging from 0.5 to 5 mA/cm² at a constant cyclic capacity throughput of 5 mAh/cm².

Our results reveal insights into the thermodynamic behavior and stability of lithium metal interfaces in different electrolyte environments and for different current densities. The calorimetric measurements provide the additional information on the heat flow associated with plating and stripping processes, shedding light on the kinetics of lithium deposition and dissolution. Furthermore, we systematically investigated the influence of electrolyte composition, including the presence of FEC and VC additives, on the interfacial properties and passivation reactions of lithium metal. In symmetrical lithium metal cells, we observed distinct heat signatures corresponding to the coulombic efficiency (CE) in Li-Cu half cells. The addition of FEC and VC additives exhibited pronounced effects on the suppression of irreversible passivated lithium depositions and the enhancement of stability at high current rates.

Our results highlight the importance of electrolyte composition in the behavior of lithium metal/liquid electrolyte interfaces. The comprehensive understanding gained from these experiments provides a basis for testing new electrolyte compositions with additional insight over conventional testing methods.
Preventing Lithium Dendrites on Fast Charging Batteries Using Interface Control
Authors: Lee Jiin , An Kihun , Tran Yen Hai Thi , Vu Dung Tien Tuan , Song Seung-Wan
Published: December 2024

Lithium (Li) dendrites often grow on the surface of graphite anode of lithium-ion batteries during charging process, particularly under harsh conditions such as high currents, high voltages (i.e., high state of charge), and low temperatures. Dendrites cause capacity fade, short-circuit, and eventually fire hazard.Addressing the dendrites-related problems, various strategies have been developed, including the formation of a stable solid electrolyte interphase (SEI) layer, modification of separator and/or electrode, etc. Herein, we will present the interfacial control technique using designed electrolyte formulation that stabilizes the SEI layer of anode and thus prevents Li dendrites. Stabilized SEI layer induces to improve the cycle life of high-nickel based Li-ion batteries and enables faster charging than conventional 0.3 C (charged in 3.3 h) under harsh conditions. In the meeting, the correlation between performance and interface stability will be discussed.
(Invited) Long-Lifetime LiMnXFe1-XPO4/Graphite Cells Enabled By Advanced Electrolytes
Authors: Leslie Kate , Aishova Assylzat , Harlow Jessie , Rathore Divya , Tuul Kenneth , James Abraham Jeffin , Metzger Michael
Published: December 2024

The increasing demand for clean energy storage and electric vehicles is highlighting the need to develop Li-ion battery materials with low cost and abundant elements.1
,
2 Positive electrode materials such as LiFePO4 (LFP) are good candidates to replace layered oxide materials due to the high relative abundance of Fe compared to other transition metals, such as Ni and Co.1 Unfortunately, LFP suffers from low energy density.2 LiMnxFe1-xPO4 (LMFP) has been proposed as an alternative to LFP. It shares the same crystal structure as LFP with a portion of Fe sites substituted with Mn. The Mn2+/3+ redox takes place at higher potential, improving the energy density.2

In this work, we set to decouple the contribution of the Fe and Mn to cell failure in order to better understand this class of olivine materials. LiMn0.8Fe0.2PO4/artificial graphite (AG) cells were cycled over varying voltage ranges to determine the capacity fade behaviour of each plateau, Fe (2.5-3.6 V) and Mn (3.6-4.2 V), as well as the full voltage range of the cell. The worst capacity fade was seen for cells cycled over the full voltage range, while very little capacity fade was seen for the Fe plateau and no capacity fade was seen for the Mn plateau, due to the Li reservoir from the negative electrode. In order to determine the capacity fade mechanism, differential voltage analysis was utilized.3 dV/dQ analysis shows no mass loss over any of the voltage ranges, large Li inventory loss for the full voltage range and Mn voltage region, and small Li inventory loss for the Fe region. X-ray fluorescence spectroscopy was used to determine the degree of Mn deposition on the negative electrode. The degree of Mn deposition was found to be well-correlated with the amount of Li inventory loss, demonstrating that the primary failure mode of LMFP/AG cells is Mn-catalyzed Li inventory loss. In order to fix that problem, we synthesized advanced LiMnxFe1-xPO4 with different values of x and optimized material properties. We also developed novel electrolytes that reduce Li inventory loss even at elevated temperature. Overall, our work shall enable long-lived LMFP/graphite cells for longer cost electric vehicles and stationary energy storage.

(1) Nitta, N.; Wu, F.; Lee, J. T.; Yushin, G. Li-Ion Battery Materials: Present and Future. Materials Today
2015, 18 (5), 252–264. https://doi.org/10.1016/j.mattod.2014.10.040.

(2) Ryu, H.-H.; Hohyun Sun, H.; Myung, S.-T.; S. Yoon, C.; Sun, Y.-K. Reducing Cobalt from Lithium-Ion Batteries for the Electric Vehicle Era. Energy & Environmental Science
2021, 14 (2), 844–852. https://doi.org/10.1039/D0EE03581E.

(3) Dahn, H. M.; Smith, A. J.; Burns, J. C.; Stevens, D. A.; Dahn, J. R. User-Friendly Differential Voltage Analysis Freeware for the Analysis of Degradation Mechanisms in Li-Ion Batteries. J. Electrochem. Soc.
2012, 159 (9), A1405. https://doi.org/10.1149/2.013209jes.
High-Capacity Fe-Rich Disordered Rock-Salt Li-Ion Cathode Materials Achieved via Redox Engineering
Authors: Fong Richie , Lee Jinhyuk
Published: December 2024

The quest for sustainable and cost-effective energy storage solutions has led to the exploration of iron (Fe)-rich disordered rock-salt (DRX) cathode materials for lithium-ion batteries (LIBs).[1-3] This study presents an approach to redox engineering in Fe-rich DRX cathodes, demonstrating the reversible Fe2+/Fe3+ redox in a Fe2+-based DRX cathode.[3] The innovative design minimizes reliance on oxygen (O) redox, yielding a high capacity of approximately 290 mAh/g and an energy density of about 700 Wh/kg. These figures surpass the performance of Fe3+-based DRX cathodes, which operate on limited Fe3+/Fe4+ redox and extensive O redox upon cycling.

The research introduces Li1.2Fe2+
0.6Nb0.2O1.4F0.6 (LFNOF), a novel Fe2+-DRX cathode material, contrasting it with Li1.2Fe3+
0.6Nb0.2O2 (LFNO), a Fe3+-DRX counterpart. LFNOF’s design leverages partial fluorine substitution for oxygen, enabling ample Fe2+/Fe3+ capacity before the onset of Fe3+/Fe4+ or O redox processes. This strategy results in reduced voltage hysteresis and improved voltage and capacity retention, leading to more stable cycling performance than LFNO. The study combines experimental and computational approaches to elucidate the redox mechanisms of LFNO and LFNOF. X-ray Photoelectron Spectroscopy (XPS), Electron Paramagnetic Resonance (EPR) spectroscopy, X-ray diffraction (XRD), and Density-Function Theory (DFT) calculations collectively confirm the accessibility of Fe2+/Fe3+ redox in LFNOF, which delays and reduces the participation of O redox, contributing to the material’s enhanced stability. Furthermore, the research highlights the potential of Fe-rich DRX cathodes in addressing the global shift towards electric vehicles and large-scale energy storage. By reducing reliance on critical mineral supply chains and leveraging Fe abundance and affordability, Fe-rich cathodes such as LFNOF can significantly enhance the economic viability of LIBs. The findings suggest that redox engineering can play a pivotal role in developing low-cost, high-performing Fe-rich cathode materials, paving the way for more sustainable and resilient energy storage technologies.

This study not only provides a novel approach to designing Fe-rich DRX cathodes but also opens new avenues for further research in battery materials. The insights gained from LFNOF’s performance could inform future developments in LIB cathode design, potentially leading to the widespread adoption of Fe-rich cathodes in commercial applications.

References

[1] J. Lee et al., Science 2014, 343, 519.

[2] H. Li, R. Fong, J. Lee et al., Joule 2022, 6, 53.

[3] R. Fong, J. Lee et al., Advanced Energy Materials 2024, 10.1002/aenm.202400402.
Unraveling the Degradation Mechanisms in Composite Solid Polymer Electrolyte through in-Situ Impedance and Ex-Situ SEM
Authors: Rusly Cindy , Chen Hsun-Yi
Published: December 2024

The increasing demand for batteries with higher energy density and enhanced safety has spurred the advancement of solid-state batteries (SSBs). While SSBs offer promising pathways to surmount the limitations of conventional batteries, their widespread adoption faces hurdles, notably due to the degradation mechanisms that impair their durability and efficacy. Among these, Li metal as anode materials acclaimed for its high energy density still encounter significant challenges related to safety and stability, primarily due to its reactive nature and formation of dendrites. Although solid-state electrolytes (SSEs) are expected to inhibit Li dendrite growth, issues with interface compatibility and dendrite penetration through SSEs remain critical barriers, underscoring the complex interplay of material properties that must be addressed to realize the full potential of SSB technologies. In this study, we delve into the failure mechanisms prevalent in SSBs by analyzing the morphology of SSEs and their interactions with electrode materials over successive cycling. Employing a combination of cycling tests, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS), we investigate the degradation patterns in lithium iron phosphate (LFP) electrodes, lithium metal, and SSEs.

The composite solid polymer electrolyte (CSPE) is synthesized by dissolving PVDF-HFP, PPC, and LiTFSi in DMF solvent, enriched with 10 wt% LLZO, and formed by slurry casting. Through our preliminary study, development of cracks in LFP electrodes was found mainly due to uneven Li stripping/plating. The aggregate formation of Li dendrite was also observed in the early charge/discharge cycles through ex-situ SEM. Significant increase in SSE porosity suggests Li formation and penetration into the CSPE for its low mechanical strength. The EDS analysis of CSPE at the end-of-life stage further reveals a notable shift towards carbon presence, likely indicating the formation of Li₂CO₃ after exposure of during transfer. This result signals high concentration of Li on the surface of CSPE. Further interphase information is revealed by analyzing the solid-electrolyte interphase (SEI) formation through in-situ impedance study. Our study offers critical insights into the mechanisms underlying the degradation of each component in the SSBs providing a foundational understanding necessary for the failure analysis of SSBs.
Strategies for Design and Synthesis Novel Sulfide-Type Na-Ion Conductors
Authors: Wang Hui , Guo Xiaolin , Halacoglu Selim
Published: December 2024

Solid-state superionic conductors play a significant role to achieve the high potential of all-solid-state batteries with high energy density and enhanced safety. Sulfide-type solid electrolytes have attracted strong interest in the past decade due to their advantages of high ionic conductivity and favorable mechanical properties. The ion transport in sulfide-type solid electrolytes is influenced by several factors, including crystal structure, synthesis approach, annealing temperature, as well as chemical doping. Specifically, anion or cation doping may cause the crystal structure changes and thus affect the conductive properties of sulfide solid electrolytes.

In this talk, we will discuss the strategies and doping chemistry in Na3MCh4 (M: P or Sb; Ch: S or Se) family conductors. For these sulfide-type Na-ion conductors, different anion or cation dopants will be introduced, and the doping effects on the synthetic process, crystal structures, as well as ionic conductivity will be systematically discussed. Moreover, the isovalent and aniovalent dopants will be compared to understand the doping strategy to design and realizer highly conductive sulfide-type solid electrolytes for solid-state Na batteries.
(Invited) Studying in-Situ Passivating Interphase between Halide Solid-Electrolyte and Li-Based Anode in All-Solid-Statebatteries
Authors: Kim Se Young , Bak Seong-Min , Jun KyuJung , Ceder Gerbrand , Chen Guoying
Published: December 2024

All-solid-state batteries (ASSBs) have been highlighted as a promising alternative for future energy storage systems due totheir high thermal stability and high energy density compared to lithium-ion batteries using liquid electrolytes. Among many types of solid electrolytes, halide solid electrolytes (SE) with high oxidative stability have been intensively proven as a feasible SE that enables cycling 4 V class cathode materials. However, undesirable thermodynamic instability of halide SEs to Li metal anode hinders achieving high energy density ASSBs for practical use. To this end, lithium-indium (Li-In) alloy has been extensively employed due to their (electro)chemical stability to halide SEs that enables stable cycling of ASSB using halide SEs. Although the decomposition of halide SEs and its reactants in direct contact with Li metal has been experimentally and theoretically studied, no in-depth investigations on interphase evolution and charge transfer mechanism at the LYC SE and Li-In anode interphase have been conducted. In this work, we report the evolution of the interphase layer between In metal anode and halide solid electrolyte, Li3YCl6 (LYC), that enables stable long-term cycling of ASSB coupled with crack-free single-crystal (SC) LiNi0.8Co0.1Mn0.1O2 (NMC811) cathode active material. Through the combination of high-resolution micro scale x-ray based analysis on a cross-section of the ASSBs, we demonstrate the cross talk between LYC and In anode that results in the evolution of interphase layer consists of InClx, YCl3, LiCl, and In diffused LYC which suppressed dendritic growth of Li-In alloy over the ASSB cycling.
Understanding Degradation Behavior in All-Solid-State Batteries through Scanning Spreading Resistance Microscopy
Authors: Gamo Hirotada , Maeda Yasushi , Kiyobayashi Tetsu , Siroma Zyun , Takeichi Nobuhiko , Sano Hikaru
Published: December 2024

All-solid-state lithium-ion batteries (ASSLIBs) are promising candidates as the next generation battery because of inherently high safety and high energy density. The practical application of high-performance ASSLIBs is to be achieved by the development of solid electrolytes (SEs) with high ionic conductivity. So far, many SEs with high ionic conductivity over 10−3 S cm−1 have been discovered. However, ASSLIBs still face challenges arising from solid/solid interfaces. ASSLIBs using sulfide SEs involve chemical and mechanical degradations at the interface between cathode materials and solid electrolytes in cathode composites during the charge/discharge process. These degradations increase total resistance in ASSLIBs, leading to cycle deterioration. Therefore, understanding the degradation behavior is important for realizing long-life ASSLIBs. Scanning spreading resistance microscopy (SSRM) is a type of atomic force microscopy technique, which provides current distribution with high spatial resolution at the sample surface. An SSRM study by Otoyama et al. reported that a part of the cathode materials in the electrode shows insufficient electron conduction paths after the charging and involves high local resistance in the domains of the cathode materials.1 The local resistance analysis using SSRM is a useful technique for unveiling the degradation behavior in ASSLIBs.

Herein, we investigate the local resistance of cathode composites with LiNbO3-coated LiNi0.5Co0.2Mn0.3O2 (NCM) and argyrodite-type SEs for ASSLIBs after charging and elucidate the degradation behaviors through ex-situ SSRM. The local resistance analysis reveals the intrinsic resistance changes of NCM particles involving lithium deintercalation. Topography and local resistance mapping obtained by ex-situ SSRM study show that a part of NCM particles in cathode composites is electrically isolated after the charging to a high potential.2 Our work demonstrates that the ASSLIBs after the charging to a high potential cause mechanical degradation due to the volume change of NCM particles.

Acknowledgments

This study is based on the results obtained in the ‘Evaluation of All-Solid-State Battery Material and Foundational Technology Development for Next Generation (SOLiD-Next, JPNP23005)’ project, commissioned by the New Energy and Industrial Technology Development Organization (NEDO).

References

M. Otoyama et al., J. Phys. Chem. C,
125, 2841 (2021).

H. Gamo et al., J. Mater. Chem. A, submitted.
Solid-State Architecture Batteries for Enhanced Rechargeability and Safety (SABERS) Beyond Li-Ion: Technology to Enable Next-Generation Sustainable Electric Aviation
Authors: Viggiano Rocco P. , Dornbusch Donald , Lin Yi , Yamakov Vesselin I
Published: December 2024

All-electric vertical take-off and landing vehicles (eVTOL) for urban air mobility (UAM) concepts face numerous challenging technical barriers before their introduction into the consumer marketplace. The primary barrier to overcome is developing an energy storage system that meets rigorous aerospace safety and performance criteria. The performance metrics for eVTOL vehicles are at least two times greater than those of electric ground vehicles. Furthermore, inherently non-flammable batteries are essential for the safe operation of commercial electric aero vehicles. The SABERS concept proposes a battery that meets the critical performance criteria by developing a solid-state architecture battery utilizing a high-capacity sulfur-selenium cathode and lithium metal anode. The combination of sulfur and selenium offers a balanced energy-to-power density ratio, which can be tailored to the specific application by altering the stoichiometric ratios of sulfur to selenium. This hybrid cathode will be developed using NASA-patented holey graphene technology as a highly conductive, ultra-lightweight electrode scaffold. A solid-state electrolyte will be used as a safe, non-flammable replacement for the highly flammable liquid organic electrolytes currently in SOA lithium-ion batteries. This solid-state lithium-sulfur/selenium cell will be designed in a serial stacking configuration to enable the dense packaging of the battery cells. The serial stacking configuration is termed a bipolar stack, which has the advantages of reducing overall cell weight, simplifying the interfaced connections for the cell, and minimizing the cooling requirements. Lastly, the optimization of battery components will occur through a robust and rigorous combination of various computational modeling techniques covering multiple length scales. The expected result will be a fully solid-state battery with operational temperatures up to 150 °C, providing the required energy density, discharge rates, and inherent safety to meet the strict aerospace mission performance criteria. The SABERS team employed novel materials development, computational modeling, and design-of-experiments (DOE) optimization studies in their research. This presentation will show the results of these studies and demonstrate a feasible path for solid-state cells with a specific energy greater than 400 Wh/kg to enable electric aircraft.

Figure 1
How Much Safer Are Solid State Cells? - Quantified Failure Analysis of Next-Generation Solid State Cells during Abuse Testing
Authors: Parks Huw Christopher William , Shearing Paul R , Robinson James B
Published: December 2024

Solid-state lithium-ion batteries offer a promising solution for electric vehicle energy storage by replacing flammable liquid organic electrolytes with non-flammable solid alternatives, thus significantly enhancing safety levels.1 However, despite this potential, the safety of these batteries remains a subject of debate due to a lack of quantified understanding, and existing standards may not adequately address anticipated failure modes. Consequently, there is a pressing need to characterize and quantify the safety of solid-state cells, considering the unique chemistry of each component. Although solid electrolytes aim to reduce the instances of soft shorts between electrode, one of the major safety concerns in solid-state batteries is the occurrence of internal short circuits (ISCs) under faliure circumstance, which pose significant challenges in terms of durability and safety, particularly in automotive applications. ISCs can lead to rapid and catastrophic discharge of up to 70% of the total cell energy in under 60 seconds, resulting in substantial self-heating and potentially initiating thermal runaway.2

To evaluate the safety of solid-state cells, abuse testing has become a standard practice, involving techniques such as nail penetration, crush testing, accelerating rate calorimetry, and overcharging. These tests expedite ISC occurrences, enabling researchers to gain insights into cell behaviour under extreme conditions and facilitating safety assessments. In this study, we conducted a comprehensive examination by subjecting commercial solid-state cells and Li-ion cells of similar energy to catastrophic failure conditions. In conducting this work, we aim to provide a comparative analysis of the challenges encountered by solid-state cells and to quantify the impact of scale-up on safety and failure events, ranging from cell capacities of 2 Ah to 10’s of Ah, and examining the propagation of failure through battery packs. To achieve this, we utilized a diverse array of abuse testing and characterization techniques, including X-ray CT, SEM, and GCMS. Through this endeavour, we aim to establish a benchmark for solid-state failure analysis and quantification, contributing to the advancement of safer battery technologies.

[1] Mauro Pasta et al 2020 J. Phys. Energy 2 032008

[2] Hossein Maleki and Jason N. Howard 2009 J. Power Sources. 2 568-574
The Critical Role of Pressure Uniformity in Enhancing the Performance and Safety of Solid-State Batteries
Authors: Kim Kyounghwan , Shin Jaeho
Published: December 2024

All-solid-state batteries represent a significant advancement in energy storage technology, offering higher safety and energy density compared to traditional liquid electrolyte solutions. As the demand for more efficient and robust energy storage solutions grows, particularly for electric vehicles and renewable energy systems, the development of solid-state batteries with the argyrodite Li6PS5Cl as the electrolyte has gained substantial attention. These batteries promise enhanced performance through improved energy density and safety.

However, optimizing these systems requires a deep understanding of the mechanical stresses involved, particularly those related to pressure dynamics within the battery cells. For stable operation of these batteries, high pressure is essential, yet studies analyzing pressure in practical, commercially viable cell configurations are notably scarce. This research focuses on the development and examination of pouch-type cells, which are instrumental in demonstrating how pressure dynamics influence battery performance and longevity in real-world applications. By meticulously monitoring these pressure variations, our study not only assesses operational efficiency but also detects potential short circuits, thereby significantly enhancing battery safety. Additionally, our findings highlight the critical role of pressure uniformity in preventing uneven lithium deposition, a common issue that can lead to performance degradation and reduce the battery's overall lifespan. Through advanced pressure management techniques, this research contributes to the design of more reliable and efficient batteries, paving the way for their commercial viability and widespread adoption
Enabling Co-Firing of Li-Garnet-Electrolyte Tapes for Li-Metal Batteries
Authors: Weinmann Steffen , Rupp Jennifer L.M. , Kim Kunjoong
Published: December 2024

Garnet-type Li7La3Zr2O12 (LLZO) with its competitive ionic conductivity (~ 1 mS cm-1), wide electrochemical stability (above 5.0 V vs. Li/Li+), and compatibility with Li-metal, is a promising electrolyte for solid-state Li-metal batteries. Despite the promise, manufacturing all-solid-state battery architectures faces challenges, mainly due to missing robust contact and high interfacial resistance on the cathode-electrolyte interface due to the evolution of secondary phases during processing. Simultaneously achieving high cathode active material loadings and low interfacial impedances remain to be shown in devices with relevant architectures. In this project, we investigate the scalable powder-to-device fabrication for a cathode/electrolyte half- and full-cell with LiCoO2 as the active material and LLZO as the ion conducting electrolyte phase, combined with a Li-metal anode. We report the electrical and ionic resistance of LLZO-LiCoO2 composite cathodes being reduced by three orders of magnitude by manipulating the sintering atmosphere. Raman spectroscopy mapping reveals the secondary phase evolution inside the LLZO due to Cobalt diffusion being absent in composite cathodes sintered in a lithium-rich atmosphere as compared to ambient conditions. Further investigations lead to the conclusive assumption that the formation of secondary phases can be blocked by stopping lithium volatilization during high-temperature co-firing. Testing the dense composite cathodes in a liquid electrolyte battery, very low initial impedances of >30 Ω and high areal capacities of 3.5 mAh cm-2 with almost full utilizations can be achieved. Such batteries can be operated at 0.25 mA cm-2 at room temperature for 50 cycles without failing. Furthermore, we demonstrate tape-cast composite cathodes with thicknesses of < 100 µm being built into such battery setups, showcasing their mechanical integrity and density. Combining these results with recently developed dense-porous Li-garnet bilayers, we give an outlook to manufacture an all-solid-state, co-fired battery architecture that operates without the need of stack pressure.
Halide-Based All-Solid-State Batteries: From Pellet Cells to Pouch Cells
Authors: Shen Fengyu , McGahan Michael , Pietras John , Doeff Marca M. , Battaglia Vincent , Tucker Mike C
Published: December 2024

Halide solid electrolytes gain significant attention due to the high ionic conductivity, low processing temperature, oxygen resistivity, high-voltage stability, and so on. However, high stack pressure is one of the bottlenecks limiting the scale-up of the halide-based solid-state batteries. In this study, pellet cells with an active area of 0.5 cm2 were studied through optimizing catholyte particle size, CAM loading and stack pressure. Discharge capacity >190 mAh/g was achieved with a high cathode loading at room temperature. The retention at 0.5 C was >80% after 200 cycles. Post-mortem analysis reveals the fading mechanism in the cathode. In addition, the cathode recipe was further optimized for scale-up. A small amount of binder was used in cathode, to balance the electrical performance and mechanical properties. The tape cast NMC cathode provides comparable electrical performance to the powder NMC cathode. Free-standing halide tape electrolyte was obtained through tape casting as well, with an area >50 cm2. Pouch cells with an active area of 12 cm2 were also assembled and cycled with a minimal stack pressure. Furthermore, the challenges for scale-up of halide-based solid-state batteries will be discussed.
Simultaneous Solid Electrolyte Deposition and Cathode Lithiation for Thin Film Batteries
Authors: Warecki Zoey , Castagna Ferrari Victoria , Ievlev Anton , Sugar Josh D , Kim Nam Soo , Stewart David Murdock , Albertus Paul , Rubloff Gary , Talin Albert Alec
Published: December 2024

Interest in thin film solid state lithium-ion batteries (TFSSLIBs) continues to grow because of their increased safety over flammable liquid electrolytes and their compatibility with well-established thin-film fabrication methods and characterization techniques. TFSSLIBs are also attractive for addressing fundamental questions because they generally comprise fewer components (no binders or conductive additives), and are commonly used to investigate the formation and evolution of solid electrode/electrolyte interfaces. TFSSLIBs are well suited to study the inherent capacity retention and rate performance of cathode materials in a symmetric battery structure, e.g., cathode/SSE/cathode. V2O5 is a candidate with a high theoretical capacity and insertion chemistry of up to 3 Li ions per V2O5, but which practically is unable to achieve highly reversible cycling of even Li2V2O5 due to the structural phase change upon lithiation. By designing a TFSSLIB model system with a solid electrolyte that forms a stable electrode/electrolyte interface, e.g. lithium phosphorous oxynitride (LiPON), in a symmetric configuration, we are able to study the performance of LixV2O5 thin film cathodes without the additional deleterious effects related to anode performance.

We will discuss the fabrication and cycling performance of two different symmetric V2O5 TFSSLIB configurations. The first is a V2O5/LiPON/LixV2O5 TFSSLIB, where the cyclable lithium in this system is included via simultaneous electrolyte deposition and lithiation of one V2O5 cathode during the RF sputtering process, as discussed in our recent publication.1 The second configuration is an LixV2O5/LiPON/LixV2O5 TFSSLIB where lithium is included during the auto-lithiation step of the first V2O5 electrode as well as during the co-sputtered deposition of the second V2O5 electrode. A comparison of the two TFSSLIB symmetric cell performances will be discussed, as well as a comparison to similar symmetric cells cycled in liquid electrolyte. We show that the deposition of the solid-state electrolyte LiPON onto thin film V2O5 leads to a uniform lithiation of up to 2.2 Li per V2O5, without affecting the Li concentration in the LiPON and its ionic conductivity. In the LixV2O5/LiPON/LixV2O5 system, we demonstrate cycling of >270 mAh/g at a rate of 20C, for 1600 cycles with only 8.4% loss in capacity.

1. Warecki, Z. et. al., Simultaneous Solid Electrolyte Deposition and Cathode Lithiation for Thin Film Batteries and Lithium Iontronic Devices, ACS Energy Lett, 2024, 9, 2065-2074
Modifying Li1.3Al0.3Ti1.7(PO4)3 electrolyte-Anode Interface with Two-Dimensional Materials for All-Solid-State Lithium Batteries
Authors: Tsai Dong-Lun , Yeh Che-Ning
Published: December 2024

The widespread adoption of lithium batteries in electric vehicles (EVs) and electronic devices is attributed to their extended cycle life and high energy density. However, the utilization of organic liquid electrolytes (LEs), which are highly flammable and volatile, has raised safety concerns. Additionally, severe side reactions between electrodes and LEs decrease the performance of lithium batteries. Recently, the replacement of LEs by solid-state electrolytes (SSEs) has emerged as a promising development for safe and high-energy-density lithium batteries.

Among these, Li1.3Al0.3Ti1.7(PO4)3 (LATP), a NASICON-type SSE, has garnered attention due to its high ionic conductivity (10-4 - 10-3 S/cm) and excellent stability in ambient conditions. However, the strong reducibility of lithium metal anode poses a risk of Ti4+ reduction, leading to the formation of a highly electronic conductive phase such as Li3Al0.3Ti1.7(PO4)3, which may accelerate lithium dendrite growth and increase interfacial resistance.

In our work, we introduce 2D material coatings (e.g., graphene, MoS2, Co3O4, etc.) at the electrode-LATP interface. Leveraging the high mechanical strength and specific surface area of 2D materials, this coating enhances the surface stability of LATP and electrodes, prevents titanium reduction, and inhibits lithium dendrite growth, thereby enhancing cycling performance. The solid-state batteries using LATP with modified coating as SSE exhibit high capacity retention compared to the batteries using bare LATP SSE. Our work provides a promising approach to SSEs with superior ionic conductivity and stability, expanding the candidates of applicable solid electrolytes toward the realization of the next-generation all-solid-state lithium batteries.