Visualizing lithium (Li) ions and understanding Li plating/stripping processes as well as evolution of solid electrolyte interface (SEI) are critical for optimizing all‐solid‐state Li metal batteries (ASSLMB). However, the buried solid‐solid interfaces present a challenge for detection which preclude the employment of multiple analysis techniques. Herein, by employing complementary in situ characterizations, morphological/chemical evolution, Li plating/stripping dynamics and SEI dynamics were efficiently decoupled and Li ion behavior at interface between different solid‐state electrolytes (SSE) was successfully detected. The innovative combining experiments of in situ atomic force microscopy and in situ X‐ray photoelectron spectroscopy on Li metal anode revealed interfacial morphological/chemical evolution and decoupled Li plating/stripping process from SEI evolution. Though Li plating speed in Li10GeP2S12 (LGPS) was higher than Li3PS4 (LPS), speed of SSE decomposition was similar and ~85% interfacial SSE turned into SEI during plating and remained unchanged in stripping. To leverage strengths of different SSEs, an LPS‐LGPS‐LPS sandwich electrolyte was developed, demonstrating enhanced ionic conductivity and improved interfacial stability with less SSE decomposition (25%). Using in situ Kelvin Probe Force Microscopy, Li‐ion behavior at interface between different SSEs was effectively visualized, uncovering distribution of Li ions at LGPS|LPS interface under different potentials.

中文翻译：

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全固态锂金属电池界面形态和化学演化的原位分析


可视化锂（Li）离子并了解锂电镀/剥离过程以及固体电解质界面（SEI）的演变对于优化全固态锂金属电池（ASSLMB）至关重要。然而，埋藏的固-固界面对检测提出了挑战，阻碍了多种分析技术的使用。在此，通过采用互补的原位表征、形态/化学演化、锂沉积/剥离动力学和SEI动力学有效解耦，并成功检测到不同固态电解质（SSE）之间界面的锂离子行为。原位原子力显微镜和原位X射线光电子能谱在锂金属阳极上的创新组合实验揭示了界面形态/化学演化以及SEI演化中的解耦锂沉积/剥离过程。尽管 Li10GeP2S12 (LGPS) 中的 Li 沉积速度高于 Li3PS4 (LPS)，但 SSE 分解速度相似，约 85% 的界面 SSE 在电镀过程中转化为 SEI，并且在剥离过程中保持不变。为了利用不同 SSE 的优势，开发了一种 LPS-LGPS-LPS 夹层电解质，该电解质具有增强的离子电导率和改善的界面稳定性，同时减少了 SSE 分解 (25%)。使用原位开尔文探针力显微镜，可以有效地可视化不同 SSE 之间界面处的锂离子行为，揭示不同电势下 LGPS|LPS 界面处锂离子的分布。