Lithium‐Ion Batteries with a Wide Temperature Range Operability Enabled by Highly Conductive sp³ Boron‐Based Single Ion Polymer Electrolytes

We report excellent operability of Li‐ion batteries equipped with selected sp 3 boron‐based single‐ion polymer electrolyte membranes (SIPEs) in the temperature range of 25–100 °C. The high performance of the batteries is attributed to the high ionic conductivity of the SIPEs, superior interfacial contacts between the SIPE membranes and the electrodes, and the sizes of the mesopores in the membranes being appropriate for ion transport. It is demonstrated that the use of organic solvents in the SIPE membranes does not lead to apparent molecular decomposition in the batteries even at temperatures as high as 100 °C, which underscores the exceptional performance of the SIPE membranes for safe operation of Li‐ion batteries with excellent thermal and electrochemical stability. The intrinsic flexibility of the membranes enables this class of materials to be used in thin and flexible battery devices.