预炭化时间对煤基活性炭孔结构及电化学性能的影响

Influence of carbonization time on pore struture and electrochemical performance of coal-based activated carbon

以太西无烟煤为前驱体,KOH为活化剂制备煤基活性炭,考察了预炭化时间对煤基活性炭孔结构及电化学性能的影响。结果表明,随着炭化时间的增加,活性炭吸附量先增大后减小,活性炭的比表面积、总孔容先增大后减小,中孔孔容逐渐减小;在预炭化温度800℃,炭化时间6 h,KOH与太西无烟煤质量比为2∶1,活化温度800℃的条件下可制备比表面积为1409 m2/g,总孔容为0.5284 cm3/g,中孔率为6.25%的煤基活性炭。电流密度为50 mA/g时,炭化6 h制备活性炭的比电容最大为127 F/g,电流密度增大至2500 mA/g时,比电容为84 F/g,容量保持率达到66.1%,经过1000次循环充放电后,其容量仍保持93.6%。

Coal-based activated carbons as supercapacitor electrode materials were prepared from Taixi anthracite with KOH as activator. The pore structure and electrochemical performance of activated carbon were characterized by adjusting carbonization time. As prolonging carbonization time, the adsorption quantity, specific surface area and total pore volume of activated carbon increase first, then decrease. The pore volume of mesopore gradually decrease. When the precarburization temperature and time is 800 ~C and 6h, the weight ratio of KOH to coal is 2, the activatied tempreture is 800 ℃, the specific surface, total pore volume, mesoporosity of prepared coal-based activated carbon can reach up to 1409 m2/g,0. 5284 cm3/g and 6.25 percent respectively. The results show that AC6 exhibit excellent specific capacitance over 127 F/g at 50 mA/g and the capacitance maintenance achieved 66. 1 percent at 2500 mA/g in organic electrolyte. The residual specific capacitance is more than 93.6 percent after 1000 cycles.