Expand the effective carriers in solid polymer electrolytes via anion-hosting cathode

Abstract

The non-reactive anion migration deteriorates the limited ionic conductivity of the solid polymer electrolytes (SPEs) and accelerates solid-state batteries failure. Here, we introduce an integrated approach in which polyvinyl ferrocene (PVF) cathode encourage anions and Li+ to act as effective carriers simultaneously. The concentration polarization and poor rate performance, caused by insufficient effective carriers, were addressed by the participation of anions in electrode reaction. Specifically, the PVF|Li battery matched with unmodified SPE (PEO-LiTFSI) showed 107 mAh g− 1 initial capacity at 100 µA cm− 2 and maintained 70% retention for more than 2800 cycles at 300 µA cm− 2 and 60°C. Moreover, the slight capacity decrease at 1000 µA cm− 2 and the successful batteries operation at minimal ionic conductivity (8.13×10− 6 S cm− 1) show that the current carrying capacity of SPEs was greatly improved without complex design. This strategy weakens the strict requirements for ion conductance and interface engineering of SPEs, and provides an efficient scenario for constructing advanced polymer-based all-solid-state batteries.