A P(VDF-HFP) and nonwoven-fabric based composite as high-performance gel polymer electrolyte for fast-charging sodium metal batteries

Although sodium metal batteries (SMBs) have drawn numerous attentions as the promising candidate for the next-generation rechargeable batteries, various issues hinder their practical applications, e.g., the growth of dendrites and large volume change of Na metal during cycling, etc.. The adoption of gel polymer electrolyte (GPE) is an effective solution to address the safety issues and increase the lifetime of SMBs. In this study, a novel composite membrane consisting of nonwoven fabric as the supporting matrix and poly (vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) as the Na+ transmission medium is easily fabricated via non-solvent induced phase inversion method. After plasticized by NaClO4-based liquid electrolyte, the obtained composite membrane exhibits an enhanced mechanical strength, high uptake to organic liquid electrolyte (115%), high thermal and electrochemical stability, superior ionic conductivity (1.38 mS cm-1) and remarkable Na ion transference number (0.47), which has been demonstrated to effectively suppress the growth of sodium dendrite, improve the fast-charging performance and cycling stability of the corresponding SMBs. This work paves a way for the commercialization of GPE in the fast-charging SMBs.