作为富含含氧官能团的有机大分子，褐煤被认为是制备富氧多孔炭材料的天然前驱体。对褐煤进行酸洗氧化改性进一步增加其氧含量得到酸洗氧化褐煤（OAWSL），以KHCO3为活化剂，在高温下分解并与碳反应生成大量气泡，气泡穿透碳层逸出形成大量孔隙，并鼓泡形成了独特的球状表面，得到了多孔炭球。同时探究了KHCO3添加量对多孔炭结构和作为超级电容器电极材料时电化学性能的影响。研究发现，酸洗氧化褐煤与KHCO3质量比为1∶3时得到的多孔炭球具有最均匀球状结构、最大微孔占有率（90.88%）和最高氧含量（22.17%）。以该多孔炭球为电极材料，在以6 mol/L KOH为电解液的三电极体系中得到了323 F/g的比电容（0.1 A/g），组装的超级电容器最大能量密度为6.17 W·h/kg，在2 A/g电流密度下循环20 000次后电容保持率为96%，库伦效率保持100%，可为褐煤基富氧多孔炭材料的制备提供理论支撑。

As an organic macromolecule rich in oxygen-containing functional groups, lignite is considered as a natural precursor for the preparation of oxygen-enriched porous carbon. Lignite modified by acid washing followed with oxidization (OAWSL) was obtained for increasing the oxygen content. With the activation of KHCO3, a large number of bubbles penetrate the carbon layer and escape to form abundant pores at high temperature, and a unique spherical surface is obtained. What′s more, the effect of the addition of KHCO3 on the structure and the electrochemical performance of porous carbon as electrode material for supercapacitors was investigated. It is found that the porous carbon spheres, which is prepared under the condition of the mass ratio of 1∶3 (OAWSL ∶ KHCO3), have the most uniform spherical structure, the largest micropore occupancy (90.88%) and the highest oxygen content (22.17%). In the electrolyte of 6 mol/L KOH, a specific capacitance of 323 F/g (at the current density of 0.1 A/g) is obtained in the three-electrode system using the porous carbon sphares as electrode material. In addition, the assembled supercapacitor has the maximum energy density of 6.17 Wh/kg. After 20 000 GCD cycles at 2 A/g, the capacitance still retained 96% of initial, and the Coulombic efficiency is always 100%. This paper can provide theoretical support for the preparation of lignite based oxygen-enriched porous carbon materials.

0 引言

1 试验

   1.1 原料和试剂

   1.2 酸洗氧化褐煤的制备

   1.3 多孔炭（PCs）的制备

   1.4 PCs的表征

   1.5 电极制备及其电化学性能测试

2 结果与讨论

   2.1 PCs的结构表征

   2.2 PCs的电化学测试

3 结论