Operando Study Insights into Lithiation/Delithiation Processes in a Poly(ethylene oxide) Electrolyte of All-Solid-State Lithium Batteries by Grazing-Incidence X-ray Scattering
Yuxin Liang, Tianle Zheng, Kun Sun, Zhuijun Xu, Tianfu Guan, Fabian A. C. Apfelbeck, Pan Ding, Ian D. Sharp, Ya‐Jun Cheng, Matthias Schwartzkopf, Stephan V. Roth, Peter Müller‐Buschbaum
Abstract
High Resolution Image Download MS PowerPoint Slide Poly(ethylene oxide) (PEO)-based composite electrolytes (PCEs) are considered as promising candidates for next-generation lithium-metal batteries (LMBs) due to their high safety, easy fabrication, and good electrochemical stability. Here, we utilize operando grazing-incidence small-angle and wide-angle X-ray scattering to probe the correlation of electrochemically induced changes and the buried morphology and crystalline structure of the PCE. Results show that the two irreversible reactions, PEO-Li + reduction and TFSI – decomposition, cause changes in the crystalline structure, array orientation, and morphology of the PCE. In addition, the reversible Li plating/stripping process alters the inner morphology, especially the PEO-LiTFSI domain radius and distance between PEO-LiTFSI domains, rather than causing crystalline structure and orientation changes. This work provides a new path to monitor a working battery in real time and to a detailed understanding of the Li + diffusion mechanism, which is essential for developing highly transferable and interface-stable PCE-based LMBs.