A composite gel polymer electrolyte for sodium metal battery at a wide temperature range

Sodium-metal batteries (SMBs) are considered a promising alternative to lithium-metal batteries due to their high-energy density, low cost, and good low-temperature performance. However, the serious side reactions and dendrites growth during the process of sodium ions deposition/stripping are the bottleneck that inhibits the further capitalization of SMBs, especially at low temperatures. Herein, a porous framework of 50 mu m thickness composite gel-polymer-electrolyte (GPE) supported by polyvinylidene difluoride nanowires membrane and Na3Zr2Si2PO12 ceramic particles is proposed to tackle the issues. This GPE not only has high ionic conductivity but also can promote the uniform transportation of sodium ions to form a stable and dense metal-GPE interfacial layer, which can effectively inhibit the side reactions and dendrites growth in a wide temperature range. The assembled Na//GPE//Na3V2(PO4)3 full battery provides a specific capacity of 100 mAh g-1 at 10 C for more than 3000 cycles calendar life at room temperature. Moreover, the full battery based on this GPE has an extraordinary performance at low temperatures, reaching a specific capacity of 93 and 61 mAh g-1 at 0.5 and 1 C at -20 degrees C, respectively. This work provides a reliable solution for low-temperature applications of high-energy density and long-cycle life SMBs. Sodium-metal batteries (SMBs) are considered a promising alternative to lithium-metal batteries due to their high-energy density, low cost, and good low-temperature performance. A porous framework of 50 mu m thickness composite gel-polymer-electrolyte (GPE) supported by polyvinylidene difluoride nanowires membrane and Na3Zr2Si2PO12 ceramic particles is proposed to improve the electrochemical performance of SMBs. This GPE not only has high ionic conductivity but also can promote the uniform transportation of sodium ions to form a stable and dense metal-GPE interfacial layer, which can effectively inhibit the side reactions and dendrite growth in a wide temperature range. The assembled Na//GPE//Na3V2(PO4)3 full battery provides a specific capacity of 100 mAh g-1 at 10 C for more than 3000 cycles calendar life at room temperature. Moreover, the full battery based on this GPE has an extraordinary performance at low temperatures, reaching a specific capacity of 93 and 61 mAh g-1 at 0.5 and 1 C at -20 degrees C, respectively. This work provides a reliable solution for low-temperature applications of high-energy density and long-cycle life SMBs.image