An electrode-composite separator assembly for a lithium battery, the electrode-composite separator assembly including an electrode; and a composite separator, wherein the composite separator includes a separator, and a coating film disposed on a surface of the separator, wherein the coating film includes a copolymer including an electrolyte-insoluble repeating unit and a repeating unit represented by Formula 1; and at least one selected from an inorganic particle and an organic-inorganic particle, wherein the electrode-composite separator assembly does not have an exothermic peak between 400° C. to 480° C. when analyzed by differential scanning calorimetry, wherein Formula 1 is wherein, in Formula 1, R3 is hydrogen or a C1-C5 alkyl group, and R4 is a C1-C10 alkyl group. Also, a lithium battery including the electrode-composite separator assembly.