Polycrystalline Li‐Rich Mn‐Based Cathodes for All Solid‐State Batteries

Abstract

ABSTRACT High‐capacity Li‐rich Mn‐based oxide cathode (LRMO) materials are promising candidates for all‐solid‐state batteries (ASSBs). While single‐crystal materials have been widely regarded as a promising strategy to enhance cycling stability in ASSBs, the potential of commercialized polycrystalline Li‐rich Mn‐based cathodes (PC‐LRMO) remains largely unexplored. Herein, we propose a simple but effective strategy to pre‐construct a stabilized, organic‐rich cathode electrolyte interface (CEI) both on the surface of PC‐LRMO cathodes and at the grain boundaries (GBs) of the secondary particles. This organic‐rich CEI facilitates low interfacial impedance and fast interfacial ion transfer kinetics. Consequently, this enhanced interfacial ion transport alleviates polarization under high‐temperature operating conditions, thereby improving the discharge specific capacity of a working battery. Furthermore, the organic‐rich CEI effectively mitigates direct contact and facilitates the formation of a self‐adaptive interface between the high‐voltage cathodes and the solid electrolytes. This adaptive interface alleviates stress and strain during charge‐discharge cycling, suppresses detrimental side reactions and voltage decay, and stabilizes the high‐voltage interface. Therefore, an improved rate capability and long‐term cycling stability of the LRMO cathode is achieved. This facile solution‐based preparation strategy provides an economically viable approach for effective utilization of emerging cathodes for ASSBs.