A versatile Co-Activation strategy towards porous carbon nanosheets for high performance ionic liquid based supercapacitor applications

Abstract Two-dimensional (2D) nanocarbons have attracted considerable researching interest in electrochemical energy storage owing to their large surface area and shortened ion-diffusion distance. Herein, we propose a versatile co-activation strategy for preparing porous carbon nanosheets by employing easily available petroleum asphalt as the precursor. Besides KOH, introducing of NaOH as the co-activating reagent not only realized the morphological change from microparticles to nanosheets, but also altered the textural properties of the products, which is totally different from the traditional template route, offers a new possibility towards 2D nanocarbons. The large specific surface area and highly-developed micropores combined with its unique structural advantages, make it a very promising electrode material for high-rate supercapacitor in ionic liquid electrolyte. For instance, the porous carbon nanosheets deliver a large specific capacitance (169 F/g 1 A/g), superior rate capability (72.8% capacitance retention at 50 A/g), and good cycling stability after 5000 cycles. Moreover, the energy density can reach to 52.3 Wh/kg even at an ultrahigh power density of 43.75 kW/kg, which have shown great potential for applications in electrochemical energy storage devices such as supercapacitors.