Loofah sponge-derived 3D flexible porous carbon electrode for high performance supercapacitor

Energy storage facilitate the substitution of clean and sustainable new energy including solar, wind and tidy energy to the pollution-produced and one-off conventional fossil. Carbon, as activated material, plays key roles in both supercapacitor and battery. Biomass-derived carbon makes fossil-free energy storage be realized. Herein, natural loofah sponge is chosen as the carbon source in supercapacitor. Based on the special network and macroscopical shape of loofah, 3D porous carbon electrode rather than powdery activated material is directly constructed. Especially, flexibility is endowed to this carbon electrode when the lignin and hemicellulose are selectively removed. 3D flexible carbon electrode prepared at the optimized conditions (FLSC-4-1000) owns a high specific surface area of 772.87 m2 g−1. In addition, FLSC-4-1000 exhibits outstanding electrochemical supercapacitor performance: A specific capacitance of 267 F g−1 at the current density of 0.5 A g−1 and a high capacitance retention of 97 % over 10,000 cycles for the electrode. Meanwhile, an energy density of 20.35 Wh kg−1 at 900 W kg−1 and 18.5 Wh kg−1 at 18.01 kW kg−1 for symmetric supercapacitor (SSC) of FLSC-4-1000//FLSC-4-1000.