Effects of particle size of petroleum cokes on material and electrochemical property of activated carbon

Taking the petroleum cokes with different distribution of particle size as raw material and KOH as activated agent,the ultra-high surface area activated carbons employed for supercapacitors were prepared by chemical activation process.The BET specific surface area and the pore structure of activated carbon were analyzed by N2 adsorption method.The electrochemical properties of the activated carbons were determined using two-electrode capacitors in 1mol/L Et4NBF4/AN electrolyte.Results indicate that the yield and tap density increases then decreases with the decreasing particle size of petroleum cokes.And the petroleum cokes with narrow distribution developed lower BET specific surface area and pore volume of activated carbons.On the other hand,the activated carbon prepared by petroleum cokes of 38μm shows the highest specific capacitance of 144F/g.And activated carbon prepared by petroleum cokes of 38-44μm shows good power discharge behavior,the specific capacitance is 126.6F/g at the current of 1A/g and 116.2F/g at the current of 20A/g,respectively,with the capacitance loss of 8.2%.