Binder for Secondary Battery, Negative Electrode for Secondary Battery Including the Same, and Lithium Secondary Battery Including the Same

Provided are a binder for a secondary battery, a negative electrode including the same, and a secondary battery including the same. More particularly, the binder for a secondary battery prepared by reacting a copolymer including specific repeating units and a crosslinking agent including two or more aldehyde groups has excellent mechanical properties and effectively improves a binding force. The negative electrode and the secondary battery including the binder for a secondary battery effectively suppress expansion of a negative electrode to manufacture a secondary battery having excellent charge/discharge cycle characteristics and battery performance.