All-solid-state lithium-ion batteries (ASSLBs) with solid state electrolytes (SSE), regarded as next-generation battery system, have attracted most of the research and industrial interest in the electrochemical storage field due to their higher energy density, wider voltage window, safety and other superior performance. Seeking promising solid-sate electrolytes with high ionic conductivity and excellent electrochemical stability plays the key role in practicing ASSLBs. Li-argyrodites show high ionic conductivity and stable electrochemical properties, which are advantageous to ASSLIBs. However, as most sulfide solid electrolytes show poor stability in air, Li-argyrodites would react with H₂O molecules in the air and release harmful H₂S gas. We have carried out first-principles calculations on the failure mechanism of Li-argyrodites based on the hydrolysis of Li₆PS₅Cl. Two possible hydrolysis paths for H₂O molecule on the Li₆PS₅Cl surface are found, with single or dual H₂O molecules, respectively. The dynamic results show that both oxygen atoms and sulfur vacancies could diffuse on the surface. However, they are difficult to migrate in the bulk. Thermodynamic calculations show that the thermodynamic stability of Li₆PS₅Cl decreases gradually with the continuous hydrolysis reaction. The effect of doping Sn in Li₆PS₅Cl is further investigated, which explains the inhibiting mechanism of Sn-doping in Li₆PS₅Cl from the perspective of kinetics. Our studies also show that Sn doping mainly inhibits the hydrolysis of Li₆PS₅Cl by preventing the decomposition of OH⁻ when involving single H₂O molecule, while it obstructs the decomposition of the absorbed H₂O when involving dual H₂O molecules.

Graphical abstract

中文翻译：

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Li-argyrodite Li6PS5Cl在空气中的水解机理

具有固态电解质（SSE）的全固态锂离子电池（ASSLBs）被认为是下一代电池系统，由于其更高的能量密度、更宽的范围，吸引了电化学存储领域的大部分研究和工业兴趣。电压窗口、安全等优越性能。寻找具有高离子电导率和优异电化学稳定性的有前途的固态电解质在实践 ASSLBs 中起着关键作用。Li-argyrodites显示出高离子电导率和稳定的电化学性能，这对ASSLIBs是有利的。然而，由于大多数硫化物固体电解质在空气中表现出较差的稳定性，Li-argyrodites会与空气中的H ₂ O分子发生反应并释放有害的H ₂S 气。我们基于Li ₆ PS ₅ Cl 的水解对Li-argyrodites 的失效机理进行了第一性原理计算。Li ₆ PS ₅ Cl 表面上的H ₂ O 分子有两种可能的水解路径，分别是单H 2 O 分子或双H ₂ O 分子。动态结果表明，氧原子和硫空位都可以在表面扩散。但是，它们很难大量迁移。热力学计算表明，随着水解反应的进行，Li ₆ PS _{5 Cl的热力学稳定性逐渐降低。}Li ₆ PS _{5中掺杂Sn的效果}进一步研究了Cl，从动力学角度解释了Sn掺杂在Li ₆ PS _{5 Cl中的抑制机理。}我们的研究还表明，Sn掺杂主要通过阻止单H 2 O分子中的OH - 分解来抑制Li 6 PS 5 Cl的水解，_{而在涉及双H 2} ^O_分子时_，它_阻碍吸附的H ₂ O的分解。 .

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