Mesoporous carbon microspheres with high capacitive performances for supercapacitors

Abstract

Novel small-mesopores-enriched porous carbon microspheres have been synthesized from carbonaceous polysaccharide microspheres, by using the associated lithium acetate treating and heat treating strategies. X-ray diffraction, scanning electron microscope, transmission electron microscopy and nitrogen adsorption-desorption techniques have been employed to investigate the as-prepared samples. The analysis results indicate that the porous carbon microspheres has a high specific surface area of 1163m2g−1 and a satisfactory small mesoporous texture (2∼5nm), with the mean pore size of 3.24nm and the pore volume ratio of 2∼5nm pores up to 92%. The capacitive performances of the samples in 6molL−1 KOH aqueous electrolyte, have been tested by cyclic voltammetry, electrochemical impedance spectroscopy and charge-discharge techniques. A specific capacitance of 171.5F/g is obtained for the porous carbon microspheres via charge-discharge at a current density of 1000mA/g. It also displayed a very high cycle stability of 97.8%, compared with the initial capacitance, after 1000 cycles at the high current density of 1000mA/g.