Na 2 TiV ( PO 4 ) 3 @C composite with excellent Na‐storage performance based on a solid‐state polymer electrolyte membrane

Na2TiV(PO4)3 compound can be used as a cathode material for sodium-ion battery for its good stability, high operating potential, and low material cost. In this work, a quasi-solid sodium-ion battery with Na2TiV(PO4)3@C as the cathode and Na-form perfluorinated sulfonic resin (PFSA-Na) membrane as the solid electrolyte were assembled and tested. It is worth mentioning that compared with liquid electrolyte battery, the quasi-solid sodium-ion battery displays better cycle and rate performance. At a different current density of 50, 100, 200, 500, and 1000 mA g−1, the quasi-solid sodium-ion battery shows specific capacities of 125, 110, 96, 73, and 45 mA h g−1, respectively. And after 300 cycles, the specific capacity still remains ~90 mA h g-1, which is far better than liquid electrolyte battery (~70 mA h g-1). The good result is due to the assembly of quasi-solid batteries and the application of PFSA-Na solid electrolyte.