Effects of high temperature treatment on the electrochemical performance of hypercoal-based activated carbon
KONG Bihua
Abstract：Research on the influence of high-temperature treatment on the electrochemical performance of activated carbon electrodes can improve the preparation process of electrode materials to enhance their energy density,provi-ding technical support for promoting their large-scale application.Hypercoal derived from lignite served as the raw material.KOH activation was used to prepare hypercoal-based activated carbon.HNO3 and ammonia were utilized as nitrogen sources to modify the hypercoal-based activated carbon with a liquid-phase impregnation followed with high-temperature treatment process.The modified materials were fabricated into supercapacitor electrodes.Activated car-bons were characterized by low temperature nitrogen adsorption and Fourier Transform Infrared Spectroscopy(FTIR).The electrochemical performance of activated carbon electrode was tested by constant current charge-discharge,cyclic voltammetry(CV)and electrochemical impedance spectroscopy(EIS).Compared with the influence on the surface structure properties and electrochemical performance with high-temperature treatment.The results show that the graphitization degree of activated carbons increases and pore structure is concentrated with high temperature treatment;Surface functional groups change significantly after two kinds of agents modified and transfer into the graphite layers.The oxygen-containing functional groups such as-COO—,C=O and C-OH were increased after high-tempera-ture treatment of HNO3,while the N-Q was mainly increased after high-temperature treatment of ammonia,while C=O and C-OH were decreased.The addition of nitrogen-containing groups can inhibit the incorporation of oxy-gen-containing groups.C=O and C-OH would be had bad effects on the diffusion resistance of the electrode mate-rial.Specific capacitance of activated carbon is 270 F/g at a current density of 50 mA/g with HNO3,the energy den-sity is 24.38 Wh/kg,demonstrating good structural characteristics and electrochemical performance.
Keywords：high temperature treatmenthypercoal-activated carbonelectrochemical propertiessupercapacitorsurface functional groupspore structure
Publication Date：2025-09-30
Pages：8( 15-22 )