An electrode including a substrate and a complex metal oxide film deposited on the surface of the substrate. The complex metal oxide film includes manganese oxide, cobalt oxide, and zinc oxide. A main component of the complex metal oxide film is manganese oxide. The stability of the electrode is enhanced by adding little amount of cobalt oxide and zinc oxide. Furthermore, a method relates to fabricate the electrode. The method utilizes a dry process, simpler one-step radio frequency magnetron sputtering to fabricate the electrode of the present invention. The process can reduce residual impurities in the electrode and then prevent the electrochemical capacitor and cell from explosion. Moreover, an electrochemical capacitor and a cell relates to of the above electrode.