Scalable Manufacturing of Solid Polymer Electrolytes with Superior Room-Temperature Ionic Conductivity

A scalable manufacturing protocol is developed to prepare polymer-based solvent-free all-solid flexible energy storage devices based on a two-roll mill and adapted rubber mixing technology. The as-prepared solid polymer electrolytes (SPEs) consisting of commercial poly(methyl methacrylate)-grafted natural rubber (MG₃₀) and lithium bis(trifluoromethanesulfonyl)imide achieve a superior ionic conductivity of 2.7 × 10^–3 S cm^–1 at 30 °C. The superior ionic conductivity is attributed to the formation of an ionic cluster network in the composite as proved by small-angle X-ray scattering and infrared spectroscopy measurements. Moreover, the as-prepared SPEs show good mechanical stability over a broad temperature range, that is , a storage modulus above 1 × 10⁴ Pa from 30 to 120 °C as indicated by the rheology data. Furthermore, the SPEs were assembled with the carbon black-filled MG₃₀ (i.e., MG₃₀C) electrode into a flexible supercapacitor cell, which had a wide voltage window of 3.5 V, good energy density of 28.4 μW h·cm^–2 at 160 °C, and good temperature tolerance up to 160 °C. This scaling-up manufacture strategy shows tremendous potential to the advancing of SPEs in applications of flexible energy storage device.