Preparation and Performance of High Activation Carbon Microbeads for Application of Supercapacitors

Carbon microbeads (CMB) were successfully prepared by glucose hydrothermal route in a stainless steel autoclave. The CMB was treated in concentrated nitric acid in order to gain the highly activated carbon microbeads (ACMB). The structure and surface morphology of as-prepared ACMB were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectrometer (FTIR), respectively. The electrochemical characteristics and capacitive behaviors of the ACMB were studied by cyclic voltammetry, current charge/discharge and cycle life measurements. The results show that the ACMB electrode has good electrochemical performance and the specific capacitance of ACMB is 291.9 F g-1 at a scanning rate of 1 mV s-1. Meanwhile, the specific capacitance of the button supercapacitor was as high as 75 F g-1 at a charge/discharge current density of 0.5 A g-1 and the loss of specific capacitance was nearly neglectable after 5000 cycles.