Reducing Gases Triggered Cathode Surface Reconstruction for Stable Cathode–Electrolyte Interface in Practical All-Solid-State Lithium Batteries

Abstract

The interfacial compatibility between cathodes and sulfide solid-electrolytes (SEs) is a critical limiting factor of electrochemical performance in all-solid-state lithium-ion batteries (ASSLBs). This work presents a gas–solid interface reduction reaction (GSIRR), aiming to mitigate the reactivity of surface oxygen by inducing a surface reconstruction layer (SRL). The application of a SRL, CoO/Li2CO3, onto LiCoO2 (LCO) cathode results in impressive outcomes, including high capacity (149.7 mAh g−1), remarkable cyclability (retention of 84.63% over 400 cycles at 0.2 C), outstanding rate capability (86.1 mAh g−1 at 2 C), and exceptional stability in high-loading cathode (28.97 and 23.45 mg cm−2) within ASSLBs. Furthermore, the SRL CoO/Li2CO3 enhances the interfacial stability between LCO and Li10GeP2S12 as well as Li3PS4 SEs. Significantly, the experiments suggest that the GSIRR mechanism can be broadly applied, not only to LCO cathodes but also to LiNi0.8Co0.1Mn0.1O2 cathodes and other reducing gases such as H2S and CO, indicating its practical universality. This study highlights the significant influence of the surface chemistry of the oxide cathode on interfacial compatibility, and introduces a surface reconstruction strategy based on the GSIRR process as a promising avenue for designing enhanced ASSLBs.