Flute-type porous carbon derived from soybean shells for high-performance all-solid-state symmetric supercapacitors

Flute-type porous carbon was successfully prepared from soybean shells through convenient methods. The influence of mass ratio on the structure and electrochemical performance of porous carbon obtained from soybean shells was investigated in detail. The obtained porous carbon exhibited a micro-tube morphology structure with a specific surface area of 2802 m² g^-1, pore volume of 1.36 cm³ g^-1, and appropriate pore size distribution. The porous carbon showed good electrochemical properties as an electrode material for supercapacitors. The optimal porous carbon SSAC4 exhibited high specific capacitance of 465 F g^-1 (1 A g^-1) and 287 F g^-1 (20 A g^-1) in a three-electrode system with 6 M KOH electrolyte. In addition, the as-assembled SSAC4-based all-solid-state supercapacitors delivered a high specific capacitance of 294 F g^-1 at 0.1 A g^-1 and excellent cycling stability of 86.2% after 10 000 cycles at 5 A g^-1.