The structure and growth of the Solid Electrolyte Interphase (SEI) region between an electrolyte and an electrode is one of the most fundamental, yet less-well understood phenomena in solid-state batteries. We present a parameter-free atomistic simulation of the SEI growth for one of the currently promising solid electrolytes (Li$_6$PS$_5$Cl), based on \textit{ab initio} trained machine learning (ML) interatomic potentials, for over 30,000 atoms during 10 ns, well-beyond the capabilities of conventional MD. This unveils a two-step growth mechanism: Li-argyrodite chemical reaction leading to the formation of an amorphous phase, followed by a kinetically slower crystallization of the reaction products into a 5Li$_2$SLi$_3$PLiCl solid solution. The simulation results support the recent, experimentally founded hypothesis of an indirect pathway of electrolyte reduction. These findings shed light on the intricate processes governing SEI evolution, providing a valuable foundation for the design and optimization of next-generation solid-state batteries.
Here, we correlate the nanoscale morphology and chemical composition of solid electrolyte interphases (SEI) with the electrochemical property of graphite-based composite electrodes. Using electrochemical strain microscopy (ESM) and X-ray photoelectron spectroscopy (XPS), changes of chemical composition and morphology (Li and F distribution) in SEI layers on the electrodes as a function of solid electrolyte contents are analyzed. As a result, we find a strong correlation between morphological variations on the electrode, Li and F distribution in SEI layer, and Coulomb efficiency. This correlati…
The solid electrolyte interphase (SEI) is regarded as the most complex but the least understood constituent in secondary batteries using liquid and solid electrolytes. The nanostructures of SEIs were recently reported to be equally important to the chemistry of SEIs for stabilizing Li metal in liquid electrolyte. However, the dearth of such knowledge in all-solid-state battery (ASSB) has hindered a complete understanding of how certain solid-state electrolytes, such as LiPON, manifest exemplary stability against Li metal. Characterizing such solid-solid interfaces is difficult due to the burie…
Measuring the buried interphase between solid electrolytes and lithium metal using neutrons
Oak Ridge National Laboratory（橡树岭国家实验室）；Brookhaven National Laboratory（布鲁克海文国家实验室）；Technical University Munich（慕尼黑工业大学）；Czech Academy of Sciences（捷克科学院）
Identification of Solid-Electrolyte Interphase Species by Joint Characterization of Li-ion Battery Chemistry by Mass Spectrometry and Electro-Chemical Reaction Networks
Bakar Institute of Digital Materials for the Planet, University of California at Berkeley（加州大学伯克利分校巴克数字材料星球研究所）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；Department of Materials Science and Engineering, University of California at Berkeley（加州大学伯克利分校材料科学与工程系）；Université de Rouen Normandie, INSA Rouen Normandie, Université de Caen Normandie, ENSICAEN, CNRS, Institut CARMeN UMR 6064（鲁昂诺曼底大学、鲁昂国立应用科学学院、卡昂诺曼底大学、ENSICAEN、法国国家科学研究中心CARMeN联合研究所）；TotalEnergies OneTech, TotalEnergies Research & Technology Gonfreville（道达尔能源OneTech、道达尔能源贡夫勒维尔研究与技术部）；Saft, Corporate Research（萨博公司企业研究部）；International Joint Laboratory-Complex Matrices Molecular Characterization (iC2MC)（国际联合实验室-复杂基体分子表征）；TotalEnergies OneTech Belgium（道达尔能源OneTech比利时）；TotalEnergies EP Research & Technology（道达尔能源勘探与生产研究与技术部）；Universite de Pau et des Pays de l’Adour, CNRS, IPREM（波城与阿杜尔地区大学、法国国家科学研究中心IPREM）
Local decomposition at the ferroelectric-antiferroelectric interphase boundaries and formation of mesoscopic structures in lead lanthanum titanate-zirconate solid solutions
The existence of passivating layers at the interfaces is a major factor enabling modern lithium-ion (Li-ion) batteries. Their properties determine the cycle life, performance, and safety of batteries. A special case is the solid electrolyte interphase (SEI), a heterogeneous multi-component film formed due to the instability and subsequent decomposition of the electrolyte at the surface of the anode. The SEI acts as a passivating layer that hinders further electrolyte disintegration, which is detrimental to the Coulombic efficiency. In this work, we use first-principles simulations to investiga…
Machine-Learning-Guided Insights into Solid-Electrolyte Interphase Conductivity: Are Amorphous Lithium Fluorophosphates the Key?
Bakar Institute of Digital Materials for the Planet, UC Berkeley（加州大学伯克利分校巴卡尔数字材料行星研究所）；Materials Sciences Division, Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室材料科学部）；Department of Materials Science and Engineering, National University of Singapore（新加坡国立大学材料科学与工程系）
The argyrodite sulfides are getting more and more attractive as highly promising solid-state electrolytes (SSEs) for high-performance all-solid-state batteries (ASSBs), owing to their high ionic conductivity, adequate plasticity, and decent mechanical strength. However, their poor incompatibility with Li metal anode and high voltage cathodes and as well as serious sensitivity to air significantly hinder their practical applications. Herein, we have devised an effective strategy to overcome these challenging shortcomings through modification of chalcogen chemistry under the guidance of theoreti…
The most promising solid electrolytes for all-solid-state Li batteries are oxide and sulfide ceramics. Current ceramic solid electrolytes are brittle and lack the toughness to withstand the mechanical stresses of repeated charge and discharge cycles. Solid electrolytes are susceptible to crack propagation due to dendrite growth from Li metal anodes and to debonding processes at the cathode/electrolyte interface due to cyclic variations in the cathode lattice parameters. In this perspective, we argue that solutions to the mechanics challenges of all-solid-state batteries can be borrowed from th…
A safe lithium-sulfur (Li-S) battery employs a composite polymer electrolyte based on a poly(ethylene glycol) dimethyl ether (PEGDME) solid at room temperature. The electrolyte membrane enables a stable and reversible Li-S electrochemical process already at 50°C, with low resistance at the electrode/electrolyte interphase and fast Li+ transport. The relatively low molecular weight of the PEGDME and the optimal membrane composition in terms of salts and ceramic allow a liquid-like Li-S conversion reaction by heating at moderately high temperature, still holding the solid-like polymer state of t…
Using cryogenic transmission electron microscopy, we revealed three dimensional (3D) structural details of the electrochemically plated lithium (Li) flakes and their solid electrolyte interphase (SEI), including the composite SEI skin-layer and SEI fossil pieces buried inside the Li matrix. As the SEI skin-layer is largely comprised of nanocrystalline LiF and Li2O in amorphous polymeric matrix, when complete Li stripping occurs, the compromised SEI three-dimensional framework buckles, forming nanoscale bends and wrinkles. We showed that the flexibility and resilience of the SEI skin-layer play…
A Perspective on Training Machine Learning Force Fields for Solid-State Electrolyte Materials
School of Materials Science and Engineering, Zhejiang University（浙江大学材料科学与工程学院）；Department of Materials Science and Engineering, Westlake University（西湖大学材料科学与工程系）
Polycrystalline solids can exhibit material properties that differ significantly from those of equivalent single-crystal samples, in part, because of a spontaneous redistribution of mobile point defects into so-called space-charge regions adjacent to grain boundaries. The general analytical form of these space-charge regions is known only in the dilute limit, where defect-defect correlations can be neglected. Using kinetic Monte Carlo simulations of a three-dimensional Coulomb lattice gas, we show that grain-boundary space-charge regions in non-dilute solid electrolytes exhibit overscreening -…
Potential jumps at transport bottlenecks cause instability of nominally ionic solid electrolytes in electrochemical cells
电化学装置如固体氧化物燃料电池（SOFC）、固体氧化物电解槽电池（SOEC）和锂离子电池（LIB）的正常操作有时会由于意外形成内相而失败。这些相包括SOEC的氧化锆电解质内的晶界处的氧气泡、全固态LIB的（石榴石型）Li 7 La 3 Zr 2 O 12电解质内的孤立的Li金属岛以及Na-S电池的Na-β-氧化铝和NASICON电解质内的类似Na金属岛。值得注意的是，虽然这些设备可以在两种极性下工作，但故障的倾向取决于极性。在这里，我们解释这些和其他现象在名义上的离子固体电解质和混合导电电极在简单的热力学和动力学方面：意想不到的内部相是由一个大的潜在的跳跃，需要推动一个恒定的离子或电子流通过其内部传输瓶颈。内相形成的明确规则，包括其极性依赖性制定，以帮助预测和减轻它，这将导致微观结构不稳定，效率恶化和击穿。
Lithium-metal batteries employing concentrated glyme-based electrolytes and different cathode chemistries are herein evaluated in view of a safe use of the highly energetic alkali-metal anode. Indeed, diethylene-glycol dimethyl-ether (DEGDME) and triethylene-glycol dimethyl-ether (TREGDME) dissolving lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium nitrate (LiNO3) in concentration approaching the solvents saturation limit are used in lithium batteries employing either a conversion sulfur-tin composite (S:Sn 80:20 w/w) or a Li+ (de-)insertion LiFePO4 cathode. Cyclic voltammetry (…
A Fibrous Solid Electrolyte for Lithium-ion Batteries
在这项工作中提出的新方法使用氧化物细丝/纤维代替致密的薄膜电解质，从而允许：（i）直接制造而不使用昂贵的薄膜生产技术，（ii）现有锂离子电池生产线的微小变化，以及（iii）更好的机械稳定性和电化学性能。采用静电纺丝技术制备了Li 7 La 3 Zr 2 O 12（LLZO）纤维作为电解质。利用X射线衍射（XRD）和扫描电镜（SEM）对产物的物相和形貌进行了表征。结果表明，所制备的电解液在电池安全性和性能方面是电动汽车用全固态电池的良好替代品。
Management of heat during charging and discharging of Li-ion batteries is critical for their safety, reliability, and performance. Understanding the thermal conductivity of the materials comprising batteries is crucial for controlling the temperature and temperature distribution in batteries. This work provides systemic quantitative measurements of the thermal conductivity of three important classes of solid electrolytes (oxides, sulfides, and halides) over the temperature range 150-350 K. Studies include the oxides Li1.5Al0.5Ge1.5(PO4)3 and Li6.4La3Zr1.4Ta0.6O12, sulfides Li2S-P2S5, Li6PS5Cl,…
Effect of lithium bis(oxalato)borate on the Structural, microstructural and electrochemical properties of blend solid polymer electrolyte
采用溶液浇铸法制备了以PEO、PVP为主体的锂离子复合聚合物电解质LiBOB，考察了LiBOB对聚合物电解质的形貌、结构和电化学性能的影响。XRD和FESEM分析表明，盐的加入提高了非晶含量。FTIR光谱证明了络合物的形成。优化体系的离子电导率比无盐体系高两个数量级，即~0.5x10-5 S cm-1（@RT），当O/Li=16时，提高到~0.65 mS cm-1（@100 oC），电导率随温度的变化符合Arrhenius性质。高的离子（~0.99）证明了络合电解质的离子性质。DSC分析表明，结晶度的抑制和玻璃熔融温度向低温移动意味着非晶含量的增加。最后，提出了一个相互作用机制，探索离子传输机制。本电解质体系可作为固态电池的潜在候选者
A Comparative Study of Molecular Dynamics Approaches for Simulating Ionic Conductivity in Solid Lithium Electrolytes
Université de Montréal（蒙特利尔大学）；Mila – Quebec AI Institute（米拉-魁北克人工智能研究所）；National Research Council Canada（加拿大国家研究委员会）；Institut Courtois, Université de Montréal（蒙特利尔大学库尔图瓦研究所）
