Thermally oxidized activated carbon with high specific surface area to boost electrochemical performance for supercapacitor

Thermally oxidized activated carbon (TOAC), acidified activated carbon (AAC) and thermally deoxygenized AC (TAC) were fabricated. The oxygen content of TOAC increased from 10.5 wt% for pristine AC to 14.8 wt%. The specific surface area of TOAC (3260.4 m2 g−1) was much higher than that of the AAC (2318.8 m2 g−1) and TAC (2811.8 m2 g−1). The TOAC obtained a high capacitance of 420.0 F g−1 at 1.0 A g−1 in the voltage range of −1.0 V ∼ 0 V, which was significantly higher than AC (287.0 F g−1), AAC (266.0 F g−1) and TAC (208.0 F g−1). The results indicated that the anchoring oxygen and large specific surface area had a synergistic effect on the capacitance performance. The plentiful oxygen could enhance the wettability between electrode and electrolyte. And the large specific surface area could provide plenty of positions for ions adsorption and accelerate the ionic diffusion and transport.