An ionic liquid enhanced gel polymer electrolyte for high performance lithium-metal batteries based on sulfurized polyacrylonitrile cathode

Abstract

Sulfurized polyacrylonitrile (SPAN) with superior cyclic stability is considered a promising cathode material for lithium-metal batteries (LMBs). However, the research on electrolyte system compatible with both cathode and anode remains limited currently. In this work, an ionic liquid enhanced gel polymer electrolyte (IL-GPE) with a freestanding fibrous structure is proposed for the highly stable LMBs. The polymer electrolyte shows uniform morphology with an average fiber diameter of 400 nm and high ionic liquid uptake. An ionic conductivity of 6.25 × 10−4 S cm−1 and an oxidative stability over 4.7 V is achieved. The addition of ionic liquid promotes uniform Li ions flux, leading to a compact electrodeposition of large Li particles. Meanwhile, the SPAN delivers a high reversible capacity of 1080 mAh g−1 after 200 cycles at 0.8 A g−1 without capacity fading. The decent rate capability performance demonstrates the fast ion transport property of IL-GPE. This work provides helpful reference for the development of electrolyte system suitable for Li||SPAN battery.