Mixed electrolyte and preparation method and application thereof

The invention relates to a mixed electrolyte and a preparation method and an application of the mixed electrolyte. The mixed electrolyte consists of an ionic liquid of dialkyl imidazolium-based diaryliodonium salt and an organic lithium salt that are equimolar. The preparation method comprises the steps of: adding N-methyl imidazole and chlorobutane into a container; then adding solvents of cyclohexane and methylbenzene; performing oil bath, rising temperature, refluxing, cooling and layering; pouring the yellow liquid in the upper layer and filtering and weighing the white crystal in the lower layer; placing the white crystal in the container, adding ethyl acetate and acetonitrile, heating, refluxing and filtering, crystallizing at -15-0 DEG C for 4-8h; re-crystallizing the crystallized product to obtain an intermediate body; dropping LiPF6 aqueous solution slowly into the intermediate body, agitating, and standing still, taking the coarse product in the lower layer and adding AgPF6 for reaction, removing wh