Disclosed is an electrolyte comprising a compound having both a sulfonate group and a cyclic carbonate group. The electrolyte forms a more stable and dense SEI layer on the surface of an anode, and thus improves the capacity maintenance characteristics and lifespan characteristics of a battery. Also, disclosed is a compound represented by the following Formula 1, and a method for preparing the same by reacting 4-(hydroxyalkyl)-1,3-dioxolan-2-one with a sulfonyl halide compound: wherein each of R1 and R2 independently represents a C1˜C6 alkylene group optionally containing a C1˜C6 alkyl group or C2˜C6 alkenyl group introduced thereto; R3 is selected from the group consisting of a hydrogen atom, C1˜C20 alkyl group, C3˜C8 cyclic alkyl group, C2˜C6 alkenyl group, halo-substituted alkyl group, phenyl group and benzyl group.