Construction of high-performance solid-state electrolytes for lithium metal batteries by UV-curing technology

Abstract

With high energy density and high safety, all-solid-state lithium metal batteries (ASSLMBs) are considered the most competitive next-generation energy storage batteries. In this work, different formulations of PEGDA-based solid-state electrolytes were prepared by solution flow casting and UV-irradiated in situ polymerization. Polyethylene oxide (PEO) was introduced to solve the problem of improving the flexibility of the substrate, and a 1:5 mass ratio between them was determined. Inorganic ceramic filler Li1.25Al0.25Zr1.75(PO4)3 (LAZP) and plasticizer butanedinitrile (SCN) were introduced to improve the ionic conductivity (σ) of the electrolyte. The best performing PP15-30-SCN sample showed a 40-fold improvement in room temperature ionic conductivity over PEGDA and lithium ion mobility number of 0.43. The ASSLMBs were assembled with composite electrolytes and tested at 60 °C. The polarization of PP15-30-SCN was significantly reduced, and the battery cycled stably at current densities from 0.1 to 2 C, with an average discharge specific capacity of 111.78 mAh g−1 at 1C. The average specific capacity at 1C was 111.78 mAh g−1. Meanwhile, the capacity retention rate was more than 99% after more than 70 long cycles at 0.5C.