双峰分级多孔炭快速制备及其电化学性能研究

Rapid preparation of bimodal hierarchical porous carbon and the investigation of its electrochemical performance

以乙酸钴为模板、柠檬酸为炭源,采用快速升降温工艺,一步模板炭化法制备出分级多孔炭。通过SEM、TEM、XPS、物理吸附等测试手段对多孔炭形貌和结构进行表征。结果显示,所得多孔炭具有典型的中孔-微孔分级孔结构,微孔集中在0.8nm,中孔集中在4 nm,比表面积达753~890 m2/g。采用三电极测试装置测试了所得分级多孔炭在6M KOH电解液中的电容性能,结果显示,随着处理温度的提高,所得分级多孔炭的电容和倍率性能均不断提高。700℃处理所得多孔炭在0.2 A/g电流密度下比电容达到144 F/g;在电流密度为5 A/g时比电容为102 F/g,电容保持率为71%,展现出较好的倍率性能。

Using rapid heating and cooling process, hierarchical porous carbon has been synthesized via the one-step template carbonization method with cobalt acetate as the template, citric acid as carbon precursor. The morphology and structure of porous carbon are characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and physical adsorption. Results show that the as-prepared porous carbon has high specific surface area （ 753-890 m^2/g ） and typical micro-mesoporous structure which micropores and mesopores peak at 0.8 nm and 4 nm, respectively. The capacitance performance of the hierarchical porous carbon is tested in three-electrode system in 6M KOH. Results show the specific capacitance and rate performance are improved with the carbonization temperature increasing. The obtained porous carbon displays superior rate capability with specific capacitance of 102 F/g at 5 A/g, which preserves 71% of its capacitance （ 144 F/g ）at 0.2 A/g.