胡萝卜基分级多孔炭材料的制备及电化学性能研究

Preparation and Electrochemical Properties of Carrotbased Hierarchical Porous Carbon

以胡萝卜为炭源,采用KOH对胡萝卜炭进行活化,制备出具有高比电容的分级多孔炭材料。利用SEM、X射线衍射分析、低温氮气吸脱附等手段对制备的材料进行形貌及结构分析,结果表明,不同碱炭比会造成炭材料不同程度的结构变化,在碱炭比为2∶1时,所制备的炭材料孔隙结构分布最佳,比表面积高达3111.45 m2/g,总孔容为1.51 m3/g。循环伏安(CV)、恒流充放电(GCD)等电化学测试表明,在最佳活化条件下制备的胡萝卜基多孔炭材料制成的电极在6 mol/L KOH电解液、0.5 A/g电流密度条件下比电容为486 F/g,表明材料具有良好的电容性能;当电流密度提升20倍时,电容量保留为原来的86%,表明材料具有良好的倍率性能;10 A/g电流密度下经8000次循环后,电容保持率为97.3%,表明材料具有良好的稳定性。胡萝卜基多孔炭材料制成的电极片所组装的水系超级电容器器件能量密度可达14.67 Wh/kg,功率密度为1000 W/kg。

Carrot carbon was used as carbon source,KOH activation method was developed to prepare highly qualified porous carbon with hierarchical pore size distribution and high specific surface area.The morphology and structure of the prepared materials were analyzed by means of scanning electron microscopy(SEM),Xray diffraction(XRD)analysis,and nitrogen adsorptiondesorption.The results showed that the different KOH to carbon ratio would cause different degree of structural changes of the carbon materials.When the alkali to carbon ratio was 2∶1,the pore structure distribution of the prepared carbon material showed the best with the specific surface area of 3111.45 m2/g and total pore volume of 1.51 m3/g.The cyclic voltammetry and constant current chargedischarge tests showed that the specific capacitance of the electrodes prepared under the optimal activation conditions was 486 F/g at 6 mol/L KOH electrolyte and 0.5 A/g current density,which indicated that the material had good electrochemical performance.When the current density was increased by 20 times,the capacitance retention was 86%of the original,which indicated that the material had good rate performance.The capacitance retention was reserved as 97.3%after 8000 test cycles at 10 A/g current density which demonstrated that the material had good stability.The energy density and power density of the waterbased supercapacitor device assembled by the carrotbased hierarchical porous carbon electrode plate could reach 14.67 Wh/kg and 1000 W/kg.