A battery includes a cathode layer, a cathode current collector on the cathode layer, an anode layer on the cathode layer, an anode current collector on the anode layer, a separator between the cathode layer and the anode layer, and an electrolyte, wherein the cathode layer includes a plurality of crystal grains of a cathode active material and aligned in a first direction, and at least one groove formed in a direction perpendicular to an upper surface of the cathode layer that is in contact with the separator, and wherein a side surface of the cathode layer exposed by the at least one groove is aligned with a crystal direction, a crystal direction, wherein h and k are integers greater than or equal to 1, or a combination thereof, of the crystal grains of the cathode active material.