Characterization of Hierarchical Porous Carbons Made from Bean Curd via K2CO3 Activation as a Supercapacitor Electrode

Progress in sustainable energy development often relies upon the idea of making use of green materials and agents to fabricate the components of high-performance energy storage devices. Herein, we show that a relatively high energy density of 11.9 Wh kg(-1) at a 0.1 A g(-1) current density in a 1 M H2SO4 solution and a stable capacitance performance for up to 10000 cycles can be achieved in a symmetric supercapacitor (SC) made of two identical hierarchical porous carbon (HPC) electrodes derived from bean curd and 10 wt.% potassium carbonate (K2CO3); both of which are non-toxic, edible materials. Such HPC, defined as HPC-10, which was made through a one-pot activation process followed by carbonization at 750 degrees C, exhibits high specific surface area of 2514 m(2) g(-1), hierarchical porous framework (i. e., simultaneous presence of abundant micropores, mesopores, and macropores), and contains N and O dopant components. In a three-electrode system, HPC-10 showed specific capacitances of 486 F g(-1) in a 1 M H2SO4 and 404 F g(-1) in a 6 M KOH, both obtained at a 0.1 A g(-1) current density. This work also evaluates systematically the porous structure and electrochemical performance of HPC as a function of K2CO3 concentration from 0 wt.% to 15 wt.%.