神东低阶煤基电容炭材料的制备及其电化学性能

Preparation of Shendong low-rank coal-based capacitive carbon materials and its electrochemical performance

为研究材料的比表面积和微孔孔体积对低阶煤基电容炭电化学性能的影响,通过调控氢氧化钾(KOH)和超低灰分神东低阶煤(SLC)的质量比,以固相活化法制备了系列不同微孔比例的煤基电容炭。利用电感耦合等离子体质谱、元素分析和氮气吸附/脱附技术对所制备的煤基电容炭进行组分分析和孔结构表征,采用恒流充放电(GCD)、循环伏安(CV)和交流阻抗(EIS)等测试手段评价煤基电容炭的电化学性能。结果表明:随着KOH和SLC质量比增大,制备的煤基电容炭的比表面积和总孔体积均呈现增加趋势(最高值分别为2736.20 m^(2)/g和1.2968 cm^(3)/g);当KOH和SLC质量比为2.0:1时,煤基电容炭的比表面积为2517.80 m^(2)/g,微孔比表面积为2485.59 m^(2)/g(占比高达98.72%),此时,微孔孔体积最大(0.0648 cm^(3)/g);煤基电容炭在有机电解液两电极体系中表现出高质量比电容特性,在0.05 A/g的电流密度下质量比电容达到173.8 F/g,在10 A/g下仍保留有159.4 F/g的质量比电容,保留率为91.72%;煤基电容炭的充放电可逆性良好,具有典型的双电层电容特性。

To investigate the impacts of specific surface area and micropore pore volume on the electrochemical performance of capacitive carbons derived from low-rank coal,a series of coal-based capacitive carbons were prepared via solid-phase activation by varying the mass ratio of potassium hydroxide(KOH)to Shendong ultra-low ash coal(SLC)(KOH-to-SLC ratio).The composition and pore structure of the capacitive carbon materials were characterized using inductive coupled plasma mass spectrometry,ultimate analysis,and nitrogen adsorption/desorption techniques,respectively.The electrochemical performance was assessed through constant current-discharge tests,cyclic voltammetry(CV),and electrochemical impedance spectroscopy.The results show that as the KOH-to-SLC ratio increases,both the specific surface area and total pore volume of the capacitive carbon materials are enhanced,reaching up to 2736.20 m^(2)/g and 1.2968 cm^(2)/g,respectively.At a KOH-to-SLC ratio of 2.0:1,the produced coal-based capacitive carbon exhibits a specific surface area of 2517.80 m^(2)/g and a micropore surface area of 2485.59 m^(2)/g,which accounted for 98.72%of the total surface area.The micropore pore volume peaked at 0.0648 cm^(2)/g.Under these conditions,the coal-based capacitive carbon demonstrates a high mass specific capacitance of 173.8 F/g in an organic electrolyte at a current density of 0.05 A/g and maintained a mass specific capacitance of 159.4 F/g at 10 A/g,showing a retention rate of 91.72%.Coal-based capacitive carbon materials has excellent charge-discharge reversibility and typical double-layer capacitance behavior.