Rigid-flexible methyl cellulose/polyvinylpyrrolidone hybrid nonporous membrane with high ionic transport for high performance sodium ion batteries

Traditionally, the combination of a porous separator and liquid electrolyte to realize efficient ion transport inside sodium-ion batteries has been considered to be prone to electrolyte leakage and short-circuit risk. In order to solve this difficulty, this paper designs the blending of “rigid” methyl cellulose (MC) and “flexible” polyvinylpyrrolidone (PVP) to prepare MC/PVP-M nonporous membranes. The “rigid” MC endows MC/PVP-M with high thermal stability and mechanical strength. The “flexible” PVP promotes MC/PVP-M high electrolyte uptake, high ionic conductivity (1.03 mS cm −1 ) and Na + transfer number (0.71) under the non-porous feature. In addition, the Na 3 V 2 (PO 4 ) 3 half-cell with MC/PVP-M nonporous membrane exhibits a high specific capacity of 108.2 mAh g −1 at 0.5C, and shows an enhanced initial specific capacity of 93.5 mAh g −1 at 3C with 93.5 % capacity retention after 600 cycles. These results show that this designed MC/PVP-M nonporous membrane has a promising prospects for application, and also provide a new idea for designing separators with high safety and high electrochemical performance.