Electrochemical performance of surface oxidized activated carbon electrodes for supercapacitor
DU Xuan WANG Cheng-yang GUO Chun-yu SHI Zhi-qiang Key Laboratory for Green Chemical Technology of State Education Ministry,School of Chemical Engineering & Technology,Tianjin University,Tianjin 300072,China
To investigate the effect of oxidation treatment of activated carbon on electrochemical performance of supercapacitor, coconut shell derived activated carbon(CC)and apricot shell derived activated carbon(APC)were modified by concentrated nitric acid(HNO_3)oxidation and then manufactured into electrodes of supercapacitors with KOH solution as the electrolyte. Nitrogen adsorption method was adopted to characterize the pores in the original and modified activated carbons and cyclic voltammogram and AC impedance tests were used to examine the electrochemical performance.It has been found that both the surface area and pore volume of the carbons decreased and the average pore size increased after HNO3 treatment.However,the specific capacitances of CCN and APC didn't reduce with the decrease of surface area and pore volume.On the contrary,their specific capacitances increased from 114 F·g~(-1)and 95 F·g~(-1)to 166 F·g~(-1)and 157 F·g~(-1),respectively,because of the increase of their pseudocapacitance.In the meantime,both the charge transfer resistance and time constant of the two activated carbons decreased significantly after modification.
【CateGory Index】： TM53