A lithium carboxylate grafted dendrite-free polymer electrolyte for an all-solid-state lithiumion battery.

A novel solid polymer electrolyte (SPE) was synthesized by a two-step polymerization process followed by mixing with solid lithium bis(tri- fluoromethane sulfonimide) (LiTFSI) salts, composed of hybrid copolymermatrices grafted with lithiumcarboxylate branched chains. The target SPE1 was based on the copolymer matrix grafted with a lithium-based precursor of LiDMPA, which was prepared by the reaction between dimethylol propionic acid (DMPA) and LiOH. The results showed that SPE1 had an ionic conductivity of 0.1 mS cm^-1 at 25 °C, and displayed an electrochemical stability window up to 5.0 V (vs. Li+/Li) at a temperature of 60 °C. The grafting of LiDMPA onto the copolymer gave the SPE1 electrolyte a special structure to ensure a homogeneous current distribution and Li ion deposition, which successfully inhibited Li dendrite growth. As a result, an all-solid-state LiFePO4/SPE1/Li battery was assembled and it presents better electrochemical performance with a high capacity retention of 98.8% at 0.2C with 127.3 mA h g^-1 after 100 cycles at 60 °C, and delivers capacities of 161.1, 86.7 and 54.5 mA h g^-1 at temperatures of 80, 40 and 25 °C, respectively. This work provides a promising route to fabricate dendrite-free solid polymer electrolytes for all-solid-state lithium-ion batteries. [ABSTRACT FROM AUTHOR]