Atomic layer deposition synthesized ZnO nanomembranes: A facile route towards stable supercapacitor electrode for high capacitance

ZnO nanomembranes (NMs) are successfully fabricated by atomic layer deposition for electrochemical supercapacitor applications. The structure and morphology of ZnO NMs are investigated by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. In order to prove their potential applications in supercapacitors, the electrochemical performance of ZnO NMs is characterized in the aqueous electrolytes (i.e., KOH, KCl, and Na2SO4). Experimental results indicate that 6 M KOH electrolyte is the most promising one, and the largest capacitance of 846 F g−1 is achieved in this electrolyte with remarkable stability. In addition, ZnO NM with 100 ALD cycles demonstrates advanced performance in all three aqueous electrolytes, mainly due to the effective ion adsorption/desorption or extraction/insertion in the electrode. The 180-min flashing of a red LED powered by ZnO NMs supercapacitors suggests great potentials of NMs electrodes in practical applications.