Decorating Flower‐Like Ni(OH)2 Microspheres on Biomass‐Derived Porous Carbons for Solid‐State Asymmetric Supercapacitors

Abstract In this work, flower‐like Ni(OH) 2 microspheres decorated on biomass‐derived porous carbons (Ni/PC) were fabricated via a facile two‐step approach for high performance supercapacitor. The as‐prepared Ni/PC offered an outstanding specific capacitance of 1960 F g −1 at 1 A g −1 current density. The Ni/PC electrode showed well capacitance retention of 85 % after 5000 cycles in alkaline electrolyte. In addition, the home‐assembled Ni‐0.3/PC//activated carbon solid‐state asymmetric device exhibited 40 Wh kg −1 high‐energy density at 800 W kg −1 power density with superior cycle stability. The superior electrochemical performances can be attributed to two aspects that the large surface of Ni/PC exposes more active sites for rapid faradic reactions, and the incorporation of N/S‐doped PC accelerates the charge transfer efficiency and improves electrical conductivity. This study provides an efficient and convenient method for the preparation of electrochemical materials combining transition metal hydroxides and biomass carbon, which can be used as electrode materials for energy storage and energy conversion.