N-doped carbon foam constructed by liquid foam with hierarchical porous structure for supercapacitor

Liquid foam is used as a soft template to construct nitrogen-doped carbon foam (CF) with hierarchical porous structure directly. After activated by KOH, the specific surface area of activated carbon foam (K-CF) is dramatically increased from 207.8 to 1121.7 m2/g which results in good rate capability, excellent stability and superior electrochemical performance with specific capacitance of 182.7 F/g at a current density of 1 A/g in 6 M KOH. The significant improvement of specific surface area and specific capacitance for K-CF can be attributed to the numerous active sites due to the hierarchical structure formed by introducing liquid foam and then the treatment of activated process.