Boosting supercapacitor performance with a cobalt hydroxide in-situ preparation orange peel biochar flower-like composite

In this study, we present a novel composite material known as Cobalt oxide/orange peel-derived biochar (CoNF@OBC), which exhibits a distinctive flower-like structure and showcases exceptional potential for high-performance supercapacitors. The CoNF@OBC composite is created by employing Co(OH)2 as a supporting material. The inherent hierarchical and porous structure of CoNF@OBC facilitates efficient flow and dispersion of ions and electrons within the electrolyte. This structural advantage results in shorter diffusion pathways and enhanced conductivity, rendering CoNF@OBC highly suitable for energy storage applications. Remarkably, CoNF@OBC demonstrates an ultra-high specific capacitance of 563 F g−1 at a current density of 1 A g−1, with an outstanding capacitance retention of 96 % even after undergoing 10,000 charge-discharge cycles. When integrated into a device, CoNF@OBC yields a specific capacitance of 124 F g−1. Furthermore, the Ragone plot for the symmetric device reveals an energy density ranging from 10 to 41 Wh kg−1, accompanied by power densities spanning from 811 to 5143 W kg−1. This remarkable performance highlights the extensive potential of CoNF@OBC in practical applications, supported by its long-term cyclic stability of 92 % after 10,000 charge-discharge cycles. This study underscores the sustainability aspect of utilizing agricultural waste, such as orange peels, as eco-friendly carbon sources. By combining these waste materials with various metal hydroxides for eco-friendly supercapacitor electrodes, promoting sustainable energy storage solutions. © 2023