Sodium ion batteries are widely considered to be a feasible, cost-effective, and sustainable energy storage alternative to Lithium, especially for large-scale energy storage applications. Next generation, safer electrolytes based on ionic liquid (IL) and organic ionic plastic crystals (OIPCs) have been demonstrated as electrochemically stable systems which show superior performance in both Li and Na applications. In particular, phosphonium‐based systems outperform most studied nitrogen‐based ILs and OIPCs. In this study triisobutyl(methyl)phosphonium bis(fluorosulfonyl)imide ([P_1i444][FSI]) OIPC mixed with 20 mol% of NaFSI or NaTFSI were combined with an electrospun polyvinylidene fluoride (PVDF) support to create self-standing electrolyte membranes, and their thermal phase behaviour and ionic conductivity were investigated and compared with the bulk electrolytes. The ability of the solid-state composite electrolytes to support the cycling of sodium metal with good efficiency and without breakdown were examined in sodium metal symmetrical coin cells. The sodium transference number was determined to be 0.21. The electrochemical performance of Na/Na₃V₂(PO₄)₃ cells incorporating the composite electrolytes, including good cycling stability and rate capability, is also reported. Interestingly, the mixed anion systems appear to outperform the composite electrolyte containing only FSI anions, which may relate to electrolyte interactions with the PVDF fibres.

钠离子电池被广泛认为是一种可行的、具有成本效益的、可持续的锂电池替代品，特别是对于大规模储能应用。基于离子液体 (IL) 和有机离子塑料晶体 (OIPC) 的下一代更安全的电解质已被证明是电化学稳定的系统，在锂和钠应用中均表现出优异的性能。特别是，基于鏻的系统优于大多数研究的基于氮的 ILs 和 OIPCs。在本研究中，三异丁基（甲基）鏻双（氟磺酰基）亚胺（[P _1i444][FSI]) 与 20 mol% NaFSI 或 NaTFSI 混合的 OIPC 与电纺聚偏二氟乙烯 (PVDF) 载体相结合，形成自立式电解质膜，并研究了它们的热相行为和离子电导率，并与本体电解质进行了比较. 在钠金属对称纽扣电池中检查了固态复合电解质以良好的效率和无击穿支持钠金属循环的能力。钠转移数被确定为0.21。Na/Na ₃ V ₂ (PO ₄ ) ₃的电化学性能还报道了包含复合电解质的电池，包括良好的循环稳定性和倍率性能。有趣的是，混合阴离子系统似乎优于仅包含 FSI 阴离子的复合电解质，这可能与电解质与 PVDF 纤维的相互作用有关。