Na3V2O2(PO4)2F Cathode for High‐Performance Quasi‐Solid‐State Sodium‐Ion Batteries with a Wide Workable Temperature Range

Solid‐state batteries have attracted significant attention due to their safety, but most studies focus on room‐temperature performance. Herein, the electrochemical performance of quasi‐solid‐state sodium‐ion batteries (SIBs) based on the perfluorosulfonate‐based polymer electrolyte (PFSA‐Na) and Na 3 V 2 O 2 (PO 4 ) 2 F (NVOPF) cathode over a wide temperature range (from −25 to 65 °C) is investigated. The quasi‐solid‐state half‐cells (Na//PFSA‐Na//NVOPF@rGO) exhibit a long‐term cycle life (88.1% capacity retention at 4 C after 1000 cycles) at room temperature. A high discharge capacity can be maintained even at a low temperature of −25 °C and it can be restored to the original value when the temperature increases again to 25 °C. Meanwhile, full‐cells (hard carbon//PFSA‐Na//NVOPF@rGO) can also deliver stable cycling performance in a wide temperature range (−25, 25, and 65 °C).