Improved performance of solid polymer electrolytes for structural batteries utilizing plasticizing co‐solvents

This study describes the formulation, curing, and characterization of solid polymer electrolytes (SPE) based on plasticized poly(ethylene glycol)‐methacrylate, intended for use in structural batteries that utilizes carbon fibers as electrodes. The effect of crosslink density, salt concentration, and amount of plasticizer has been investigated. Adding a plasticizing solvent increases the overall performance of the SPE. Increased ionic conductivity and mechanical performance can be attained compared to similar systems without plasticizer. At ambient temperature, ionic conductivity (σ) of 3.3 × 10−5 S cm−1, with a corresponding storage modulus (E′) of 20 MPa are reached.