Abstract: The present disclosure provides an additive for an electrolyte for a lithium battery, an electrolyte, and an electrochemical device. The additive includes a compound represented by the following formula I, wherein R1, R2, R3, and R4 are identical to or different from each other, and are independently selected from a group consisting of hydrogen, halogen, substituted or unsubstituted C1-C20 alkyl, and substituted or unsubstituted C6-C18 aryl, and a substituent of the substituted or unsubstituted C1-C20 alkyl or the substituted or unsubstituted C6-C18 aryl can be halogen, C1-C20 alkyl, or C6-C18 aryl; wherein denotes a single bond or a double bond; and wherein n is 1 or 2.