Metal salt additive for electrolyte of liquid/solid-state lithium battery

The invention discloses a metal salt additive used in a liquid/solid-state lithium battery electrolyte, and relates to the technical field of battery materials, the metal electrolyte additive is an ionic metal salt XYn, X is a metal cation, Y is a halide ion and/or an acid radical ion, and n is an integer greater than or equal to 2. The metal cations are one or more of copper ions, silver ions, indium ions, tin ions, zinc ions and magnesium ions, and the halogen ions are one or more of fluorine ions, bromine ions and chloride ions; according to the metal salt additive used in the electrolyte of the liquid/solid-state lithium battery, the metal salt additive provided by the invention is low in cost, small in usage amount and obvious in effect, the electrolyte preparation mode is simple and convenient, the polarization voltage of the battery during first charging can be effectively reduced, and the service life of the battery is prolonged. A stable alloy/inorganic interface layer is rapidly formed, rapid transm