An isocyanate electrolyte solution additive containing a sulfamide structural group has a structure of formula I: where R1 and R2 are identical or different, R1 and R2 are each independently selected from methyl, ethyl, butyl, methoxy, methanesulfonyl, ethanesulfonyl, fluorosulfonyl, trifluoromethanesulfonyl, perfluoroethylsulfonyl, benzenesulfonyl, alkyl-containing benzenesulfonyl, cyano/fluorobenzenesulfonyl and alkoxy-containing benzenesulfonyl, and R1 and R2 can be linked to form one of five-membered ring or six-membered ring.