Electrolyte and preparation method and application thereof

The embodiment of the invention relates to an electrolyte and a preparation method and application thereof, and belongs to the technical field of aqueous zinc ion batteries. The embodiment of the invention aims to solve the technical problems of low utilization efficiency of a zinc metal negative electrode, low capacity of a positive electrode material and contradiction between the cost of an electrolyte system and the performance of the zinc ion battery in the practical application of the existing zinc ion battery. The electrolyte provided by the embodiment of the invention comprises a water-based electrolyte and a solvent, wherein the solvent is seawater, and the water-based electrolyte comprises negative electrode metal ions which can be reduced and deposited into metal at the negative electrode in the charging and discharging process, and the metal can be reversibly oxidized and dissolved. According to the embodiment of the invention, alkali metal cations in seawater can be utilized to form an electrostat