High supercapacitive stability of spray pyrolyzed ZnO-added manganese oxide coatings

Zinc oxide (ZnO) has recently been reported to exhibit electrochemical supercapacitive properties. We demonstrate, for the first time, a nanocrystalline (3O4 phase with a nanocrystalline structure. ZnO may dissolve in manganese oxide and inhibit the grain growth of the manganese oxide. Cyclic voltammetry showed that the specific capacitance (SC) of the manganese oxide coating in 1 M Na2SO 4 electrolyte increased from 196 F/g to 230 F/g at 25 mV/s for 5 at% ZnO-added manganese oxide. After activation, the cycling efficiency of the composite electrode exhibited a high value of >90% for up to 1200 cycles for all the compositions.