Hierarchical porous self-supporting graphite carbon electrodes based on the biomimetic structure for supercapacitors

Abstract

Regulating pore structure, improving conductivity, and reducing the influence of binders are considered important ways to improve the performance of carbon-based electrode materials for supercapacitors. This study successfully prepares a highly graphitized hierarchical porous self-supporting carbon electrode without the need for binders, conductive agents, and current collectors using low-cost and abundant pine wood as the precursor and K2FeO4 as the activator and catalyst. The self-supporting electrode inherits the biological structure of biomass and forms a large number of micro mesopores through activation, showing an excellent 3D interconnected pore structure, and achieves a high degree of graphitization with the ID/IG ratio of being only 0.47. The self-supporting electrode facilitates the effective transport of electrolyte ions and electrons, demonstrating excellent electrochemical performance. It achieves an area specific capacitance of 3.64 F cm−2 under a current density of 5 mA cm−2. Two identical self-supporting electrodes are employed to construct a symmetric supercapacitor. The supercapacitor exhibits an energy density of 148.61 μWh cm−2 at a power density of 1 mW cm−2, with a capacity retention rate of 89.26 % after 10,000 charge-discharge cycles.