A facile in situ approach to ion gel based polymer electrolytes for flexible lithium batteries

Abstract

Inherent safety and stability issues arising from the use of traditional organic liquid electrolytes in lithium-based batteries are currently limiting their application to flexible electronics and large-scale energy storage from renewable sources. Gel polymer electrolytes (GPE) with chemical cross-linked structures and green ionic liquids as plasticizers represent a solution to this problem. In this study, a novel type of GPE with an interpenetrating polymer network (IPN-GPE) is prepared by a simple in situ thermally induced free radical polymerization. The as-prepared IPN-GPE with cross-linked structure displays a combination of high flexibility and deformability as well as thermal stability (over 310 °C). Moreover, IPN-GPE possesses a superior electrochemical stability window (5 V vs. Li⁺/Li) as well as a considerable ionic conductivity of 1.3 × 10⁻³ S cm⁻¹ at 30 °C. Therefore, with such an IPN-GPE gel electrolyte membrane, Li/IPN-GPE/LiFePO₄ devices deliver superior stable charge/discharge profiles and remarkable cycling performance and rate capability. This simple, effective and low-cost in situ synthesis strategy makes IPN-GPE one of the most promising polymer electrolyte candidates for next generation rechargeable lithium-based batteries with highly elevated electrochemical performance and safety.