Hydroxyl-functionalized poly(trimethylene carbonate) electrolytes for 3D-electrode configurations

Abstract

Polymer electrolytes were prepared from an aliphatic polycarbonate with 10 mol% of repeating units having a hydroxyl-functional side group, with the addition of LiTFSI salt. The hydrogen bond-interacting side groups were found to be beneficial for improving adhesion to 2D planar electrode material surfaces. These favorable surface properties proved to be valid also for 3D-structured systems since thin, conformal coatings could be cast on 3D-microstructured electrodes. In addition, the electrolytes were found to have reasonable ionic conductivity (up to 2.7 × 10⁻⁸ S cm⁻¹ at 25 °C and 2.3 × 10⁻⁶ S cm⁻¹ at 60 °C) that was almost independent of salt concentration. This demonstrates how a hydroxyl-functional polymer approach is suitable for the creation of 3D-structured electrode–electrolyte assemblies for microbattery applications.