The Polymer Society of Korea

Abstract

All-solid-state batteries with sulfide electrolytes are promising for next-generation storage because of their high ionic conductivity and safety. Yet, applying high-nickel layered oxide cathodes (NCM) remains difficult due to interfacial instability, structural degradation, and rapid capacity fading. In this study, a fluorine coating was introduced on high-Ni NCM to stabilize the cathode–electrolyte interface and limit side reactions with the sulfide electrolyte. The coating reinforced structural integrity, resulting in improved cycling stability and higher capacity retention. Electrochemical evaluation confirmed enhanced compatibility between the cathode and electrolyte, mitigating key degradation mechanisms. These results show that fluorine surface modification is an effective strategy to address intrinsic drawbacks of Ni-rich cathodes in sulfide-based all-solid-state batteries, offering design insights for future high-energy-density systems.

This research was supported by the National Research Foundation (NRF) funded by the Korean government (MSIT) (No. RS-2025-00562734).
This research was supported by Basic Science Research Program through National Research Foundation of Korea funded by Ministry of Science and ICT of Korea (No. RS-2025-02217276).