Improvement in electrochemical capacitance of activated carbon from scrap tires by nitric acid treatment

Activated carbon （AC） obtained from the industrial pyrolytic tire char is treated by concentrated nitric acid （AC-HNO3） and then used as the electrode material for supercapacitors. Surface properties and electrochemical capacitances of AC and AC- HNO3 are studied. It is found that the morphology and the porous texture for AC and AC- HNO3 have little difference, while the oxygen content increases and functional groups change after the acid treatment. Electrochemical results demonstrate that the AC-HNO3 electrode displays higher specific capacitance, better stability and cycling performance, and lower equivalent series resistance, indicating that AC obtained from the industrial pyrolytic tire char treated by concentrated nitric acid is applicable for supercapacitors.