Effects of a high-performance, solution-cast composite electrolyte on the host electrospun polymer membrane for solid-state lithium metal batteries

Abstract

Dispersed nano-silica fillers in poly (ethylene oxide) were solution cast on a host electrospun polyacrylonitrile membrane. The host electrospun polyacrylonitrile membrane enhanced the overall elasticity and ionic conductivity of the composite polymer electrolyte membrane for solid-state lithium metal batteries. Three different concentrations of silica fillers were added (1%, 3%, and 5%) called CSE 1, CSE 3, and CSE 5. The composite electrolyte membranes were compared with the 0% concentration of silica fillers and named SE. Among them, the CSE 3 membrane outperformed and delivered an ionic conductivity of 7.1 × 10 −4 S cm−1, lithium-ion transference number of 0.62, and the ultimate tensile strength of 27.3 MPa with 110.9% strain, revealing the elasticity of the CSE 3 membrane. The thermal stability of up to 354 °C and the wide range of electrochemical stabilities of up to 5.1 V were achieved. The symmetric cell Li|CSE 3|Li showed satisfactory long operation of lithium plating/stripping for 500 h without a significant voltage drop or short circuit. Furthermore, the electrode surface showed the homogeneous deposition of lithium on the plated electrode and a relatively smooth surface on the stripped electrode. The LCO|CSE 3|Li exhibits better rate capability and excellent cycling performance with 91.1% capacity retention and maintains 131.9 mAh g−1at 0.5C after 200 cycles.