Electrolyte additive, electrolyte for batteries including electrolyte additive, and secondary battery including electrolyte

The present invention relates to an electrolyte additive including a compound represented by Chemical Formula 1, an electrolyte including the electrolyte additive, and a secondary battery including the electrolyte. Rand Rare each independently an alkylene group having 1-5 carbon atoms; Eis a bond, an alkylene group having 1-3 carbon atoms, or a cyclic carbonyl group, ether group, or ester group having 2-5 carbon atoms; Ris a substituted or unsubstituted linear or cyclic carbonate group, carbonyl group, ether group, phosphate group, sulfonate group, or sulfate group having 2-5 carbon atoms; the substitution refers to substitution with one or more selected from F, Cl, Br, and I or an alkenyl group having 1-3 carbon atoms; Eis a bond or a saturated or unsaturated alkylene group or ether group having 1-3 carbon atoms; and n is 0 or 1.