Star Brush Block Copolymer Electrolytes with High Ambient-Temperature Ionic Conductivity for Quasi-Solid-State Lithium Batteries

We report high-performance star brush block copolymer electrolytes (SBBCEs) composed of 2-arm star polymer of [poly[poly(ethylene glycol) methyl ether acrylate]b-polystyrene](2). The physically crosslinked structure endows SBBCEs with excellent thermal stability and considerable mechanical strength, high ionic conductivity of 2.1 X 10(-4) S cm(-1) at 28 degrees C, wide electrochemical stability window up to 5.6 V, and good interfacial compatibility with lithium anode. Assembled LiFePO4 vertical bar SBBCE vertical bar Li and Ni-rich Li-Ni0.89Co0.09Mg0.02O2 vertical bar SBBCE vertical bar Li cells deliver superior ambienttemperature cycling performance with high reversible capacities, high Coulombic efficiency, and outstanding cyclic stability at considerable rate of 0.5 C. This proposed idea of employing physically crosslinked structure of brush block copolymer without any chemical crosslinker may broaden a new way to design high-performance polymer electrolytes.