Preparation method of fluoroethylene carbonate

The invention discloses a preparation method of fluoroethylene carbonate as electrolyte additive. Cyclic chloroethylene carbonate and hydrogen fluoride are employed as raw materials, reaction is performed under the protection of nitrogen and the reaction temperature is controlled to be 50-120 DEG C, a mixture including the fluoroethylene carbonate is obtained after the reaction; and then the required product of fluoroethylene carbonate is obtained through purifying by distillation. According to the preparation method provided by the invention, the material is low in cost and easy to obtain, the process route is simple, no solid waste is generated, the product yield is more than 95%, and hydrogen fluoride waste gas and hydrogen chloride waste gas are absorbed by lye, so that basically no environmental pollution is generated.