We report excellent operability of a lithium-ion battery with a gel membrane of an sp3 boron-based single ion polymer, lithium poly(1,2,3,4-butanetetracarboxylic acid borate) (LiPBAB), as the electrolyte. The battery exhibits outstanding performance in a wide temperature range of 25–100 °C with high ionic conductivity of 2.9 × 10−4 S cm−1, high electrochemical stability of 4.3 V, a large cationic transference number t+ of 0.89 and an excellent mechanical strength of 33 MPa at room temperature. The remarkable cyclic stability of the battery at 100 °C demonstrates exceptional device safety enabled by the electrolyte membrane.
