It is a big challenge to improve the energy density of the carbon-based supercapacitors for wide applications. In this work, considering the properties of redox electrolytes, functionalized porous carbon has been synthesized with interconnected pores and oxygen functional groups, which is employed to well hold the redox electrolyte ions. As a result, the functionalized porous carbon shows a high capacitance of 454 F g-1 at a current density of 1 A g-1 and can maintain 88% of the initial capacitance after 10 000 charge-discharge cycles at 10 A g-1. Especially, the as-prepared asymmetric supercapacitor obtains high energy density of 36.9 W h kg-1 at the power density of 225 W kg-1. This new design strategy by coordinating carbon materials with the redox electrolytes will guide the development of high-energy density supercapacitors.
Keywords: energy density; heteroatom doping; porous carbon; redox electrolyte; supercapacitors.