The present disclosure relates to a cathode including a cathode active material and poly(amic acid). When the lithium secondary battery including the cathode is in an abnormal operation range of 160° C. or higher, condensation reaction of poly(amic acid) occurs to form polyimide. The polyimide surrounds cathode active material particles in the form of a coating film and prevents transport of lithium ions and electrons to interrupt current flow, and inhibits abnormal heat emission and thermal runaway or combustion caused by additional reactions.