新型煤基微晶炭的制备及电容特性研究  

Preparation and capacitance characteristics study of new coal-based microcrystalline carbon

作　　者：鲍倜傲 王振帅 马爱玲 邢宝林 张传祥 侯磊 袁绍辉 赵晶 郭梦瑶 BAO Ti-ao;WANG Zhenshuai;MA Ailing;XING Baolin;ZHANG Chuanxiang;HOU Lei;YUAN Shaohui;ZHAO Jing;GUO Mengyao(College of Chemistry and Chemical Engineering,Henan Polytechnic University,Jiaozuo 454000,China;Henan College of Industry & Information Technology,Jiaozuo 454000,China)

机构地区：[1]河南理工大学化学化工学院,河南焦作454000 [2]河南工业和信息化职业学院,河南焦作454000

出　　处：《洁净煤技术》2019年第3期68-74,共7页Clean Coal Technology

基　　金：河南省教育厅高校重点科研项目(19A440002);河南省矿产资源绿色高效开采与综合利用重点实验室开放基金资助项目(KCF201802);国家级大学生创新创业训练计划项目(201810460018)

摘　　要：超级电容器具有广泛的应用领域,但由于传统活性炭在能量密度和导电性方面不能充分满足社会对超级电容器的需求,严重限制了其在大型储能装置中的应用。因此,研发具有更高储能性能的材料具有重要意义。本文以资源丰富的太西无烟煤为前驱体,采用预炭化-KOH活化联合工艺制备新型煤基微晶炭,并将其用作超级电容器电极材料。利用X射线衍射(XRD)、低温N2吸附等手段表征煤基微晶炭的微晶结构及孔结构参数,并利用恒流充放电,循环伏安,交流阻抗等探究对应电极材料的电化学性能。结果表明,煤基微晶炭含有大量较为完整的类石墨微晶结构,且随着碱炭比用量的增加,类石墨微晶结构被逐步破坏,其层间距d002由0.3915nm逐渐增至0.4059nm。在碱炭比4∶1、活化温度800℃、活化时间为2h的条件下,可制备出比表面积为928m2/g、总孔容为0.527cm3/g、中孔率为26.46%的微晶炭。将该煤基微晶炭用作电极材料在以1mol/L(C2H5)4NBF4/PC为电解液的超级电容器中,表现出优异的电化学性能:50mA/g的电流密度下比电容为94.8F/g,能量密度可达40.3Wh/kg,在500mA/g电流密度下1000次循环后比电容保持率为87.3%,具有良好的循环稳定性,并且在阻抗曲线中体现出更小的离子扩散阻力和内部阻抗。首次充电过程中充电曲线发生折转,发生了“电活化”现象。这时,微晶炭片层周围的电解液离子和溶剂分子进行插层作用,利用片层空间充分储存电子以提高能量密度。煤基微晶炭的电容特性主要由插层电容和双电层电容2部分组成,其中“电活化”现象所造成的插层电容是决定微晶炭较高能量密度的主要原因。新型煤基微晶炭优异的电化学性能与其微晶结构和丰富的孔隙结构密切相关。The supercapacitor has a wide range of applications.However,the traditional activated carbon can't fully meet the needs of the society in terms of energy density and electrical conductivity,which severely limits its application in large-scale energy storage devices.Therefore,it is of great significance to develop materials with higher energy storage performance.In this paper,a new coal-based microcrystalline carbon was prepared by preliminary carbonization coupled with KOH as activator process with abundant Taixi anthracite and used as electrode material for supercapacitor.The microstructure and pore structure parameter of the coal-based microcrystalline carbon was characterized by the methods of X-ray diffraction and low temperature N2 adsorption-desorption.The electrochemical performances of the corresponding electrode material were also investigated using galvanostatic charge/discharge,cyclic voltammetry and ac impedance.The results show that the coal-based microcrystalline carbon contains a large number of relatively complete graphite-like microcrystalline structure,and with the increase of alkali/carbon ratio,the graphite-like microcrystalline structure is gradually destroyed,and its layer spacing d 002 gradually increases from 0.391 5 nm to 0.405 9 nm.The microcrystalline carbon with a specific surface area of 928 m2/g,total pore volume of 0.527 cm3/g and mesoporosity of 26.46% can be prepared at 800 ℃ for 2 hours under the alkali/carbon ratio 4.The coal-based microcrystalline carbon applied as electrode materials for supercapacitor exhibits an excellent electrochemical performance in (C2H5)4NBF4/PC electrolyte.The specific capacitance of microcrystalline carbon is 94.8 F/g at a current density of 50 mA/g and the energy density reaches to 40.3 Wh/kg and at a current density of 500 mA/g,the initial specific capacitance is retained 87.3% after 1 000 cycles.It has good cycle stability and also shows smaller ionic diffusion resistance and internal impedance in the impedance curve.In the first charging process

关 键 词：无烟煤 微晶炭 电极材料 电化学性能 

分 类 号：TD98[矿业工程—选矿] TQ127.11[化学工程—无机化工]