Direct Visualization of Aging Effects in Metal Sulfide-based All-Solid-State Battery Cathodes

Abke, Niklas M.; Hanf, Lenard; Hendriks, Theodoor A.; Kuratani, Kentaro; Tomonari,Takeuchi; Sakaebe, Hikari; Winter, Martin; Nowak, Sascha; Wiemers-Meyer, Simon

Zusammenfassung

Lithium ion batteries (LIBs) have dominated rechargeable energy storage, but their limits necessitate next-generation solutions. Lithium sulfur batteries (LSBs) offer higher energy densities with sulfur's cost-effective and ecological advantages. Especially LSBs with solid-state electrolytes (SSEs) show promise as a next-generation solution while being plagued with low cycling reversibility. This research project involves the in-depth analysis of cycled SSE LSBs with titanium sulfide cathode active materials (CAM) and a chlorine-rich argyrodite SSE. After electrochemical aging, post-mortem analysis was carried out by combining focused ion beam (FIB) milled craters with time-of-flight secondary ion mass spectrometry (ToF-SIMS) imaging to provide new insights into the different aging effects of SSE LSBs. ToF-SIMS is a surface sensitive analysis technique that enables high mass as well as high lateral resolution imaging by combining the fast-imaging mode with delayed ion extraction. Thus, the atomic and molecular distributions acquired by ToF-SIMS imaging with FIB cross sections give insights into different aging effects of SSE LSBs. By measuring the different components and listing them as a database, the identification of newly formed species as well as the individual particles in a composite was enabled. This work shows among others the formation of a carbon-electrolyte interphase, the accumulation of sodium, the degradation of the metal polysulfide and the decomposition of the SSE. By revealing different aging mechanisms, this research takes part in paving the way for long-lasting, energy dense, and safe SSE LSBs as a more environmentally friendly alternative to conventional commercial LIBs. [1], [2]