Construction of Iron/cobalt Disulfides Nanoparticles Anchored on Biomass-Derived Hierarchically Porous Carbon for Hybrid Supercapacitors with Ultrahigh Energy Density

The rational design and preparation of cathode and anode materials with high capacitance within both positive and negative potential windows for hybrid supercapacitors remains a great challenge. Herein, a hybrid supercapacitor with ultrahigh energy density is assembled with biomass-derived iron/cobalt disulfides immobilized on porous carbon (FeS2/CoS2 @KC) and N, S co-doped porous carbon (NSKC) as cathode and anode materials. These two electrode materials are prepared by a facile impregnation and pyrolysis method. FeS2/CoS2 @KC-800 cathode material exhibits excellent electrochemical performance with a superior specific capacitance of 3480.47 F g−1 at 0.5 A g−1 and high capacitance retention of 60.35% at 15 A g−1. NSKC-800 anode material delivers a high specific capacitance of 268.75 F g−1 at 0.5 A g−1. Remarkably, the assembled hybrid supercapacitor outputs an ultrahigh energy density of 200.20 Wh kg−1 at a power density of 463.19 W kg−1. Moreover, it also possesses remarkable cycling stability with improved capacitance retention of 94.79% after 10,000 cycles at 5 A g−1. This work demonstrates that kelp is a promising precursor to construct high-performance electrode materials for energy storage applications.