Electrochemical Modified Solid Electrolyte with a Li–Al–O Interface Layer for Improved Room-Temperature Rate Performance of Solid-State Lithium Batteries

Abstract

Solid polymer electrolytes have good flexibility and are considered as a candidate material for high-energy density solid-state lithium batteries (SSLBs), which can effectively increase the capacity density. However, the lifetime and safety issues of the SSLBs caused by the growth of lithium dendrites hinder their practical applications. Herein, we demonstrate a simple in situ electrochemical method to form a Li–Al–O fast lithium-ion conductive layer between the lithium anode and the solid electrolyte interface. This method is also used to effectively inhibit the growth of lithium dendrites and achieve the long cycle life of SSLBs. The results show that at 0.25 mA·cm–2, the lithium symmetrical cell can be cycled stably for 1600 h, achieving uniform lithium plating and stripping. The Li/LiFePO4 cell exhibits a capacity retention rate of 85.6% after 300 cycles. This novel method of electrochemical interface modification constructs a high-performance solid polymer electrolyte with higher safety and longer cycle life.