Polyol carbonate bisulfate compound and preparation method thereof

The invention provides a polyol carbonate bisulfate compound and a preparation method thereof. The preparation method comprises the following steps: A) in a solvent, reacting polyol with carbonyl diimidazole to obtain a carbonic ester compound, and reacting the carbonic ester compound with thionyl chloride or thionyl diimidazole to prepare a polyol carbonic ester bisulfite compound; or reacting the polyol with the thionyl chloride or the sulfinyl diimidazole to obtain a sulfite compound, and then reacting the sulfite compound with the carbonyl diimidazole to prepare a polyol carbonate bisulfite compound; and B) in a solvent, oxidizing the polyol carbonate bisulfite prepared in the step A) by using an oxidizing agent to obtain the polyol carbonate bisulfate compound. The preparation method provided by the invention has the advantages of high reaction yield, stable yield, suitability for industrial production, high product purity and capability of meeting the use requirements of the lithium battery electrolyte