中低温煤焦油沥青基多孔炭的制备及其电化学性能

Preparation and electrochemical properties of medium-low-temperature pitch-based porous carbon

以中低温煤焦油沥青为原料,采用KOH活化法,制备了一系列多孔炭材料。利用XRD、Raman、碘吸附值、氮气吸附-脱附和电化学性能测试对不同活化温度下多孔炭材料的结构和电化学性能进行了表征与测试。结果表明,经KOH活化后的多孔炭材料具有石墨微晶和无定形碳共存的结构特征,炭材料表面具有丰富的微孔结构,同时具有较好的电化学性能。当活化温度为750℃时,多孔炭材料PC-750的BET比表面积可达1 207 m^(2)/g,微孔率为86.74%,活化过程中,温度是控制炭材料形成微孔的关键因素。多孔炭材料PC-750在0.5 A/g的电流密度下比电容为281.6 F/g,电流密度增大到10 A/g时,容量保持率可达到78.3%。交流阻抗测试显示,此材料内阻较小,是一种良好的电极材料。

A series of porous carbons(PC) materials are prepared by the KOH activation method with the use of medium-low-temperature coal tar pitch as the raw materials.The structure and electrochemical properties of porous carbon materials which prepared at different activation temperatures were characterized by XRD,Raman, iodine adsorption, nitrogen adsorption-desorption and electrochemical tests, respectively.The results show that the porous carbon materials which are activated by KOH have the structural characteristics of the coexistence of graphite microcrystalline and amorphous carbon, and that the surface of the carbon materials has abundant microporous structure with preferable electrochemical performance.When the activation temperature is 750 ℃,the obtained porous carbon material(PC-750) owns the BET specific surface area of 1 207 m^(2)/g and the microporosity is 86.74%.During the activation process, temperature is the key factor on controlling the formation of micropores in carbon materials.The specific capacitance of PC-750 under the current density of 0.5 A/g is 281.6 F/g, and the capacity retention rate can reach 78.3% when the current density increases to 10 A/g.Electrochemical impedance spectrum result shows that porous carbons material(PC-750) is a preferable kind of electrode material for its less internal resistance.