Ce(NO3)3 as an electrolyte additive to regulate uniform lithium deposition for stable all-solid-state batteries

All-solid-state lithium metal batteries (LMBs) have attracted extensive attention because of their high energy density and good safety performance. But the ionic conductivity at low temperature and dendritic growth hinder their further development. In this work, a flexible all solid-state electrolyte consisted with Ce(NO3)3, lithium bis (fluorosulfonyl) imide (LiFSI), and poly(ethylene oxide) (PEO) is synthesized. Ce(NO3)3 as an effective additive can enhance the ionic conductivity of solid polymer electrolytes (SPEs) by regulating Li+ transporting and stabilizing the interface between lithium metal anode and electrolyte by forming a stable and uniform solid electrolyte interphase (SEI) on lithium metal anode surface. The as-prepared electrolyte exhibits a good ionic conductivity of 1.6 x 10-4 S cm-1 at 60 degrees C and a wide electrochemical window of 4.4 V. The Li//Li symmetric cell with PEO + LiFSI+1%Ce(NO3)3 electrolyte displays a long cycling lifespan of over 1100 h at 0.1 mA cm-2 at 60 degrees C. Moreover, the corresponded LiFePO4 (LFP)//Li cell exhibits a long cycling lifespan of 300 cycles and excellent rate capability. This work proposes an effective additive to improve ionic conductivity and stabilize the Li metal/electrolyte interface.