Mastering high ion conducting of room-temperature all-solid-state lithium-ion batteries via safe phthaloyl starch-poly(vinylidene fluoride)–based polymer electrolyte

Abstract

In this work, an all-solid-state biomaterial electrolyte derived from phthaloyl starch and poly(vinylidene fluoride) (PVDF) was introduced. Phthaloyl starch (PS) was prepared with the starch and the phthalic anhydride via a chemical method. The introduction of C=O group through the starch esterification improved the migration of the lithium ions in the all-solid-state electrolyte membrane. The AC impedance test revealed that the addition of the phthaloyl starch promoted the conductivity of electrolytes, which can reach up to 2.04 × 10−4 S cm−1 at room temperature, and the electrochemical stability window (ESW) can achieve 4.20 V. Herein, the phthaloyl starch-PVDF–based electrolyte membrane possessed the lithium-ion transference number of 0.396. The half-cell Li/SPE/LiFePO4 had a better charge and discharge performance, that is, 93.9 mAh g−1 and 92.2 mAh g−1 after the 50th cycle at 0.5 C and at room temperature.