Sodium-ion battery electrolyte for high-voltage layered oxide positive electrode

The invention belongs to the related technical field of sodium-ion batteries, and discloses a sodium-ion battery electrolyte for a high-voltage layered oxide positive electrode, the electrolyte comprises an organic solvent, an electrolyte salt and an additive, the organic solvent is a carbonate-based solvent without ethylene carbonate; the electrolyte salt is sodium salt; the additive comprises a positive electrode film-forming additive and a negative electrode film-forming additive, the positive electrode film-forming additive comprises at least one of sodium tetraphenylborate, sodium tetrafluoroborate, sodium difluoro (oxalato) borate and trimethylsilyl phosphate, and the negative electrode film-forming additive comprises at least one of sodium tetraphenylborate, sodium tetrafluoroborate, sodium difluoro (oxalato) borate and trimethylsilyl phosphate. The negative electrode film-forming additive comprises at least one of fluoroethylene carbonate, ethylene sulfate and tetravinyl silane. The electrolyte can ef