COPOLYMER

A copolymer that exhibits a positive temperature coefficient (PTC) effect and an oxidation potential which are controlled according to objectives. Such a conductive copolymer cannot affect or can rather improve, in a normal state, performance and operation of a secondary battery by exhibiting excellent electrical properties such as low resistance, and can form, in an abnormal state, a current collector for an electrode, an electrode, and a secondary battery including same. Also provided is a use of the copolymer.