A reactive solution with an amount of 250 mL is made of distilled water and LiOH·H2O (4M) melted in the distilled water. Then, the reactive solution is put in a flow-type reactor, and is flown in between an anode electrode and a cathode electrode set in the flow-type reactor at a given temperature and a given flow rate. Then, a given voltage is applied between the anode electrode and the cathode electrode with dropping an oxidizer of hydrogen peroxide (H2O2) into the reactive solution to form a lithium-cobalt oxide thin film on the anode electrode.