Song Ce, Wang Jinyan, Meng Zhaoliang, Hu Fangyuan, Jian Xigao
School of Mathematical Sciences, Dalian University of Technology, No.2 Linggong Road, Gaoxin District, Dalian, Liaoning, China.
State Key Laboratory of Fine Chemicals, Liaoning Province Engineering Research Centre of High Performance Resins, Dalian University of Technology, No.2 Linggong Road, Gaoxin District, Dalian, Liaoning, China.
Chemphyschem. 2018 Jul 5;19(13):1579-1583. doi: 10.1002/cphc.201800070. Epub 2018 Apr 17.
Graphene oxide has become an attractive electrode-material candidate for supercapacitors thanks to its higher specific capacitance compared to graphene. The quantum capacitance makes relative contributions to the specific capacitance, which is considered as the major limitation of graphene electrodes, while the quantum capacitance of graphene oxide is rarely concerned. This study explores the quantum capacitance of graphene oxide, which bears epoxy and hydroxyl groups on its basal plane, by employing density functional theory (DFT) calculations. The results demonstrate that the total density of states near the Fermi level is significantly enhanced by introducing oxygen-containing groups, which is beneficial for the improvement of the quantum capacitance. Moreover, the quantum capacitances of the graphene oxide with different concentrations of these two oxygen-containing groups are compared, revealing that more epoxy and hydroxyl groups result in a higher quantum capacitance. Notably, the hydroxyl concentration has a considerable effect on the capacitive behavior.
由于氧化石墨烯相较于石墨烯具有更高的比电容，它已成为超级电容器极具吸引力的电极材料候选物。量子电容对特定电容有相对贡献，这被认为是石墨烯电极的主要限制，而氧化石墨烯的量子电容却很少受到关注。本研究通过采用密度泛函理论（DFT）计算，探究了在其基面带有环氧基和羟基的氧化石墨烯的量子电容。结果表明，通过引入含氧基团，费米能级附近的总态密度显著增强，这有利于量子电容的提高。此外，还比较了具有不同浓度这两种含氧基团的氧化石墨烯的量子电容，结果表明更多的环氧基和羟基会导致更高的量子电容。值得注意的是，羟基浓度对电容行为有相当大的影响。
