Argyrodite Li₆PS₅Cl with high Li⁺ conductivity is a promising material for solid-state electrolytes (SSEs) in all-solid-state lithium batteries (ASSLBs). However, the narrow electrochemical window of Li₆PS₅Cl limits its applications in ASSLBs with high energy densities, and those that consist of high-voltage cathode materials and metallic lithium anodes. Unstable lithium deposition and stripping at interfaces is also a factor that restricts its industrialization. Herein, the authors investigated the electrochemical stability of Li₆PS₅Cl using it as both the cathode and electrolyte. The Li₆PS₅Cl-C/Li₆PS₅Cl/Li cell and symmetric Li/Li₆PS₅Cl/Li cells failed after a certain number of cycles, and subsequently healed electrochemically. This failure/healing phenomenon recurred during the cycling process. The self-healing behavior is closely related to the electrochemical window, which suggests that it can be controlled by the charge–discharge voltage range. In-depth X-ray photoelectron spectroscopy, in situ Raman spectroscopy, and in situ electrochemical impedance spectroscopy revealed the reversible Li₆PS₅Cl decomposition and metallic lithium growth inside the electrolyte during the cycling process. This self-healing behavior is mainly attributed to the reciprocating lithium growth and reversible redox reaction of the Li₆PS₅Cl decomposition. The proposed self-healing mechanism is a key aspect for sulfide-based SSEs, guiding the interface modification, and material design of ASSLBs.

中文翻译：

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Li6PS5Cl基全固态锂电池前所未有的自愈效果

具有高 Li ⁺电导率的Argyrodite Li ₆ PS ₅ Cl是一种很有前途的全固态锂电池 (ASSLB) 固态电解质 (SSE) 材料。然而，Li ₆ PS ₅ Cl狭窄的电化学窗口限制了其在具有高能量密度的 ASSLB 以及由高压正极材料和金属锂负极组成的 ASSLB 中的应用。界面处不稳定的锂沉积和剥离也是制约其产业化的因素。在此，作者使用Li ₆ PS ₅ Cl 作为正极和电解质研究了其电化学稳定性。Li ₆ PS ₅ Cl-C/Li₆ PS ₅ Cl/Li 电池和对称 Li/Li ₆ PS ₅ Cl/Li 电池在循环一定次数后失效，随后通过电化学方式修复。这种失效/愈合现象在循环过程中反复出现。自愈行为与电化学窗口密切相关，这表明它可以通过充放电电压范围来控制。深度 X 射线光电子能谱、原位拉曼光谱和原位电化学阻抗谱揭示了可逆的 Li ₆ PS ₅循环过程中电解液中的 Cl 分解和金属锂生长。这种自愈行为主要归因于锂₆ PS ₅ Cl 分解的往复式锂生长和可逆氧化还原反应。所提出的自愈机制是硫化物基 SSE 的一个关键方面，指导 ASSLB 的界面修饰和材料设计。