Study on Meso-C/MnO2 asymmetric supercapacitors

Abstract

Mesoporous MnO2 and mesoporous carbon were prepared using silica mesoporous molecular sieves (SBA-15) as a hard template. A meso-C/MnO2 asymmetrical supercapacitor was assembled and characterized in 6 mol· L-1 KOH electrolyte. Low X-ray diffraction (LXRD), transmission electron microscopy (TEM), and nitrogen adsorption- desorption results indicated that the as-prepared samples had mesoporous structures, large specific surface areas, and a narrow pore diameter distribution range. Galvanostatic charge/discharge, cyclic voltammetry, and AC (alternating current) impedance were used to investigate the electrochemical performance. At 0.1 A· g-1 current density, different potentials were applied to obtain the optimum cell voltage of 1.8 V. Under this condition, the supercapacitor exhibited good charge/discharge capacities. Results showed that the equivalent series resistance (ESR), power density, and energy density were 1.15 &ohm, 89.0 W· kg-1, and 31.3 Wh· kg-1, respectively. The initial specific capacitance was 76.7 F· g-1 and 69.5 F· g-1 was obtained after 1000 cycles. © Editorial office of Acta Physico-Chimica Sinica.