Pseudocapacitance properties of AC/LiNi1/3Co1/3Mn1/3O2 asymmetric supercapacitor in aqueous electrolyte

NH2NH2·H2O which was used as controlling agent was applied to prepare the precursor Ni1/3Co1/3Mn1/3(OH)2 in the hydroxide co-precipitation method. The precursor was used to synthesize LiNi1/3Co1/3Mn1/3O2. The samples were characterized by XRD, XPS and SEM. It has been found that sintered sample at 800 °C for 16 h is considered as the optimal synthetic condition. The LiNi1/3Co1/3Mn1/3O2 was used as positive electrode and the activated carbon as negative electrode of the asymmetric supercapacitor. The electrochemical capacitance performance was tested by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge. The results indicate that species of aqueous electrolyte, current density, scan rate and potential limit, etc. have influence on the capacitance property of AC/LiNi1/3Co1/3Mn1/3O2 supercapacitor. The initial discharge specific capacitance of 298 F g−1 was obtained in 1 mol L−1 Li2SO4 solution within potential range 0–1.4 V at the current density of 100 mA g−1 and was cut down less than 0.058 F g−1 per cycling period in 1000 cycles. The asymmetric supercapacitor exhibited a good cycling performance.