Electrochemical impedance model assisted optimization of biomass hierarchical porous carbon electrode for supercapacitors

Abstract

The development of cost-effective and straightforward methodologies for the fabrication of high-performance electrode materials represents a crucial advancement in the application and evolution of supercapacitors (SCs). Hierarchical porous carbon materials have been considered a kind of promising materials for SCs owing to high specific surface area and excellent electronic conductivity. Herein, synthesis of structurally controllable porous carbon from pomelo peel by carbonization, template method and activation treatment. In addition, the impedance model is used to evaluate the charge storage capacity and ion transmission rate of porous electrodes of SCs. Biochar was prepared by using CaCO3 and KOH as template and activator, respectively, and the effects of different template and activator contents on the specific surface area, pore volume, morphology and electrochemical properties of the prepared biochar materials were investigated. The as-prepared biochar, designated as 800-PAC-750-1:1 possessed a hierarchically porous framework owning a relatively higher specific surface area of 2384 m2/g, with a specific capacitance of 240.3 F/g at a current density of 0.5 A/g. 800-PAC-750-1:1 also exhibited excellent cycling stability with 87.5% capacitance retention after 10000 cycles.