Self-organized hierarchically porous carbon coated on carbon cloth for high-performance freestanding supercapacitor electrodes

In this work, a facile method is proposed for the fabrication of self-organized hierarchically porous carbon coated on carbon cloth. The method is based on the thermal treatment of potassium citrate gel, which is derived from mixture of citric acid and potassium hydroxide. The as-prepared porous carbon derived from citrate gel generally covers carbon cloth with fine morphological properties and the sample can be directly used as an electrode material for supercapacitor. In a three-electrode configuration, the optimized electrode exhibits a remarkable specific capacitance of 379.5F g−1 at a current density of 1 A g−1. In addition, a good cycle stability with capacity retention of 97% is achieved after 10,000 cycles at a current density of 10 A g−1. Moreover, a symmetric supercapacitor is prepared by using the as-prepared electrode. The supercapacitor shows a high energy density of 0.69 mWh cm−3 at a power density of 4.91 mW cm−3 and good cycle durability and mechanical flexibility. The porous carbon material reported in this work shows potential as electrode for flexible all-solid-state supercapacitors.