The invention discloses an
electrolyte and a battery. The
electrolyte comprises a
solvent, a
lithium salt and an additive, the
solvent comprises
acetonitrile and
carboxylic ester, the additive comprises a first additive, a second additive and a third additive, the first additive is at least one of
phosphate, borate, fluorophosphate and fluoborate with a film-forming potential of 1.3-2V, and the third additive is at least one of
lithium salt and fluoborate with a film-forming potential of 1.3-2V. The second additive is at least one of a
sulfur-containing additive, a
boron-containing additive and a
phosphorus-containing additive, and the third additive is a negative
electrode film-forming additive; and Y is more than 0.025 and less than 60. According to the invention, a
solvent system and an interface film forming mechanism of the
electrolyte are synergistically regulated and controlled, so that the core problem of violent
side reaction between the
acetonitrile-based electrolyte and the negative
electrode is solved, and meanwhile, the combination of
high energy density and ultrafast charging performance is realized. The electrolyte is suitable for high-energy-density, wide-temperature-range and fast-charging type
lithium iron phosphate batteries.