Trapping Anions to Govern the Li⁺ Local Coordination Environment for a Highly Li⁺ Conductive Solid Polymer Electrolyte

Solid polymer electrolytes (SPEs) confront the major challenge of low ionic conductivity. The Li+ local coordination environment in SPEs affects the ionic conductivity. Herein, a highly ionic conductive SPE is designed and experimentally realized via governing the Li+ local coordination environment through 4-acetylphenylboronic acid (APBA). The –OH functional groups in APBA react with F atoms in the PVDF-HFP polymer chain segment and O atoms in TFSI– to form the OH···F hydrogen bond and the OH···O hydrogen bond. This weakens the Li+ local coordination with PVDF-HFP and TFSI–, facilitating more free-Li+ release and strengthening the molecular dynamics of Li+. This variation results in the greatly increased Li+ ionic conductivity from 0.63 × 10–4 to 2.39 × 10–4 S/cm of SPE with APBA at 25 °C. This electrolyte makes the symmetric cells full cells with promising electrochemical performance. The strategy provided here is helpful for the development of highly ionic conductive SPEs.