A cathode includes a cathode active material layer including a cathode active material; and a coating layer that is disposed on the cathode active material layer and that includes a block copolymer, wherein the block copolymer includes at least one first block that forms a structure domain and a second block that forms an ion conductive domain, and a total amount of the first block is in a range of about 20 weight percent to about 80 weight percent based on the total weight of the block copolymer.