纳米CaCO3模板法合成石油沥青基多孔类石墨烯炭材料

Synthesis of porous graphene-like carbon materials for high-performance supercapacitors from petroleum pitch using nano-CaCO3 as a template

  • 摘要: 利用纳米CaCO3模板耦合原位KOH活化方法合成出超级电容器用多孔类石墨烯炭材料(PGCMs)。采用透射电子显微镜、拉曼光谱、X射线光电子能谱和N2吸脱附技术对PGCMs进行了表征。结果表明,PGCMs的比表面积为1 542~2 305 m2 g-1,其取决于模板、KOH/沥青的比例和活化温度。当模板/沥青比为1.5、KOH/沥青比为1.5,在850℃恒温1 h所得PGCM的超电容性能最佳。同时,PGCMs具有相互连接的类石墨烯炭层和丰富的分级短孔。在6 M KOH电解液中,0.05 A g-1电流密度下,超级电容器用PGCMs电极的比容高达293 F g-1;在20 A g-1电流密度下,其电容保持为231 F g-1,显示了良好的倍率性能;经7 000次循环充放电后,其电容保持率为97.4%,展现了优异的循环稳定性。此外,在BMIMPF6离子液体电解液中,0.05 A g-1电流密度下,PGCMs电极的比容高达267 F g-1。PGCMs超级电容器的能量密度达148.3 Wh kg-1,其相应的平均功率密度为204.2 W kg-1。本工作为利用廉价的纳米CaCO3模板合成高性能超级电容器用石油沥青基多孔类石墨烯炭材料提供了一种可行的方法。

     

    Abstract: Porous graphene-like carbon materials (PGCMs) for supercapacitors were synthesized from petroleum pitch by a nano-CaCO3 template strategy combined with KOH activation. The PGCMs were characterized by TEM, XPS, Raman spectroscopy and N2 adsorption. Results show that their specific surface areas are 1 542-2 305 m2 g-1, depending on the template/pitch ratio, KOH/pitch ratio and activation temperature. The PGCMs feature interconnected graphene-like carbon layers with abundant small pores. The optimum supercapacitor electrode is produced when the PGCM is synthesized with a template/pitch ratio of 1.5, a KOH/pitch ratio of 1.5 at 850℃ for 1h. It has a specific capacitance of 293 F g-1 at a current density of 0.05 A g-1, an excellent rate capability with a capacitance of 231 F g-1 at a current density of 20 A g-1 and an outstanding cycling stability with a 97.4% capacitance retention after 7 000 cycles in a 6 M KOH aqueous electrolyte. It also exhibits a high specific capacitance of 267 F g-1 at a current density of 0.05 A g-1, and a high energy density of 148.3 Wh kg-1 at a power density of 204.2 W kg-1 in a BMIMPF6 ionic liquid electrolyte. This is a possible method for the synthesis of PGCMs for high-performance supercapacitors.

     

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