Highly Conductive and Stable Composite Polymer Electrolyte with Boron Nitride Nanotubes for All‐Solid‐State Lithium Metal Batteries

/Li cell based on PVDF-HFP/BNNT also exhibits excellent cyclic performance, maintaining a capacity retention of 96.4% after 400 cycles at 1C and 25 °C. Furthermore, the introduction of BNNTs is shown to enhance the thermal conductivity and flame retardancy of the CSE.