Preparation and properties of self‐healable solid‐state polymer electrolytes based on covalent adaptive networks enabled by disulfide bond

Abstract

AbstractCovalent adaptive networks (CANs) have numbers of versatile abilities derived from topological reshuffling with interesting potentials. Here, self‐healable solid‐state polymer electrolytes were developed by integrating epoxy‐resin‐based CANs enabled by disulfide bond with a solid lithium salt (LiTFSI). The disulfide bond was introduced by using a disulfide‐containing aliphatic polyamine as the epoxy‐curing agent. To determine the cure cycle of this epoxy‐resin system, the curing kinetics in the presence of LiTFSI was studied by nonisothermal differential scanning calorimetry. The prepared ion‐conducting (IC) CANs with different LiTFSI content were optically transparent and self‐healable at temperatures above glass transition temperature (Tg). The effect of LiTFSI content on the thermal stability and tensile properties was investigated. The electrical properties of the IC CANs were studied by impedance spectroscopy at various temperatures. Their ionic conductivity was analyzed by the Vogel–Tamman–Fulcher model and equivalent‐circuit fitting. Due to the high mobility of charge carriers, the IC CAN sample (containing15 wt% LiTFSI) exhibited the best ionic conductivity, which reached a value of 3.35 × 10−6 S cm−1 at 80 °C and 8.31 × 10−6 S cm−1 at 100 °C, presenting great attraction for self‐healing iontronics.