Synthesis and elucidation of electrochemical characteristics of nanorods, microsized and nanosized CuO as cathode materials for Zn/CuO alkaline battery

摘要

Discharge characteristics of nanorods )(NRs), microsized and nanosized copper )(II) oxide )(CuO) particles prepared via thermal decomposition and thermal oxidation routes are examined as cathode materials of a Zn/CuO cell without membrane separators. The electrochemical discharge is examined galvanostatically at a current density of 500 mAg(-1) and reveals that the first discharge cycles of all the CuO materials contain one potential plateau; subsequent discharge cycles involve three potential plateaus. Each potential plateau is due to an electrochemical reaction. The first, second, and third potential plateaus are attributed to Cu2O3, CuO, and Cu2O discharges, respectively. Moreover, the first and the second plateaus are higher than the plateau of the early discharges. The electrochemical performance of CuO as a cathode material is enhanced by improving its morphology and changing its size. Nanorod CuO exhibits more specific energies, 317 Whkg(-1), in the first discharge cycle, than microsized and nanosized CuO. The maximum current efficiencies of subsequent discharges are near 100 % at charging rates of 250, 500, 1000, 2000, 3000, and 4000 mAg(-1) within 60 s for each. In addition, significant alterations in charge transfer resistances )(Rct) and capacitive loops of Nyquist plots are observed during the charge/discharge of the cells through electrochemical impedance spectroscopy )(EIS).