Facile Li-ion conduction and synergistic electrochemical performance via dual functionalization of flexible solid electrolyte for Li metal batteries

Abstract

Herein, a novel polymer electrolyte membrane based on poly(arylene ether sulfone)-g- poly(vinylethylene carbonate)/poly(ethylene glycol) (PAES-g-PVEC/PEG) combined with 1-butyl-1-methylpyrrolidinium bis(trifluoromethyl sulfonyl)imide was prepared to achieve the superior electrochemical performance with good thermal and mechanical stability. The synergistic effect was provided for the lithium ion transport and electrochemical performance by the dual functional groups of polyether and polycarbonate grafted on the rigid PAES backbones. The membrane containing 30 mol% PVEC and 70 mol% PEG exhibited the ionic conductivity of 0.81 × 10 − 3 S cm −1 and Li + transference number of 0.65 at room temperature, maintaining the thermal and mechanical stability in the flexible solid state. As this membrane illustrated a good interfacial compatibility with Li metal electrode, the LiFePO 4 ||Li cell demonstrated an outstanding cycling discharge capacity of ∼151 mA h g −1 and the coulomb efficiency 99% after 100 cycles under 0.1C. Based on this excellency, the PAES-g-PVEC/PEG electrolyte herein synthesized is considered to be a promising candidate for the application of all-solid-state lithium metal batteries with high power and energy density. • PAES-g-PVEC/PEG was synthesized to prepare flexible solid electrolyte membranes. • Enhanced single Li + conduction was realized by dual functional grafts. • It exhibited Li + conductivity of 0.81 × 10 −3 S cm −1 and transference number of 0.65. • It showed quite low interfacial resistance with Li metal anode.