Abstract

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 Na₃V₂(PO₄)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.