物理化学学报 >> 2014, Vol. 30 >> Issue (2): 297-304.doi: 10.3866/PKU.WHXB201312233

电化学和新能源 上一篇    下一篇

石墨烯氧化程度对Ni(OH)2赝电容性能的影响

贺园园, 张晋江, 赵健伟   

  1. 南京大学化学化工学院, 生命分析化学国家重点实验室, 南京210008
  • 收稿日期:2013-10-21 修回日期:2013-12-23 发布日期:2014-01-23
  • 通讯作者: 赵健伟 E-mail:zhaojw@nju.edu.cn
  • 基金资助:

    国家自然科学基金(51071084,21273113,21121091,11204120)与国家科技攻关计划(2012BAF03B05)资助项目

Influence of Graphene with Different Oxidation Degrees on Nickel Hydroxide Pseudocapacitor Characterization

HE Yuan-Yuan, ZHANG Jin-Jiang, ZHAO Jian-Wei   

  1. State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210008, P. R. China
  • Received:2013-10-21 Revised:2013-12-23 Published:2014-01-23
  • Contact: ZHAO Jian-Wei E-mail:zhaojw@nju.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (51071084, 21273113, 21121091, 11204120) and National Key Technology R&DProgramof China (2012BAF03B05).

摘要:

基于密度泛函理论(DFT)设计了一系列不同氧化程度的还原氧化石墨烯片(rGNOs)并研究了其表面的氧化缺陷与吸附的氢氧化镍(Ni(OH)2)之间的相互作用. 结果发现,rGNOs表面的含氧基团与Ni(OH)2之间的吸附能与含氧基团的氧化程度相关. 在吸附Ni(OH)2后,rGNOs的原子间距和电荷分布的变化也都受rGNOs表面的含氧缺陷的氧化程度影响. 理论计算的结果与实验观察的结果一致并能给出合理的解释.我们用简单的恒电位电化学沉积法有效地在rGNOs表面制备了粒径只有5 nm的Ni(OH)2纳米粒子. 在Ni(OH)2/rGNOs制备过程中,氧化石墨烯的电化学还原是关键步骤. Ni(OH)2上吸附的Ni(OH)2因具有更高的吸附能而使其与在镍膜表面直接吸附的Ni(OH)2(在5 mV·s-1下比电容为656 F·g-1)相比具有更高的比电容值(在5 mV·s-1下为1591 F·g-1).rGNOs在吸附Ni(OH)2后构型和电荷分布的变化导致Ni(OH)2具有更低的等效串联电阻和更佳的频率响应.Ni(OH)2/rGNOs优异的赝电容特性表明其有潜力成为新型赝电容器材料.

关键词: 氢氧化镍, 氧化缺陷, 原子间距, 电荷分布, 吸附能, 赝电容

Abstract:

We designed a series of models of reduced graphene oxide sheets (rGNOs) with different oxidation degrees and then studied the interactions between oxidation defects on rGNOs and nickel hydroxide (Ni(OH)2) using density functional theory (DFT). The adsorption energy between the oxygen-containing groups on rGNOs and Ni(OH)2 is dependent on the oxidation degree of rGNOs. The variations of atomic distances and charge distribution of the oxide-defected graphene after absorbing Ni(OH)2 suggested that the oxygen-containing groups on rGNOs improve the characteristics of Ni(OH)2 as a pseudocapacitor. These theoretical results agree well with available experimental observations and give an explanation for some experimental results. We also introduce a simple potentiostatic electrodeposition method, with which Ni(OH)2 nanoparticles about 5 nm in diameter were effectively dispersed on the substrate via induction of oxidation defects on rGNOs. In the fabrication of Ni(OH)2/rGNOs, electrochemical reduction of graphene oxide is the key process. The stronger adsorption results in Ni(OH)2/rGNOs have higher rate pseudocapacitance (1591 F·g-1 at 5 mV·s-1) compared with that of Ni(OH)2 on bare nickel (656 F·g-1 at 5 mV·s-1). The variations of the geometries and charge distributions of the rGNOs after absorbing Ni(OH)2 lead to the lower equivalent series resistance and better frequency response of Ni(OH)2/rGNOs than Ni(OH)2/Ni. The high capacitance of Ni(OH)2/rGNOs indicates that Ni(OH)2/rGNOs have the potential of being used as the electrode material of pseudocapacitors.

Key words: Nickel hydroxide, Oxidation defect, Atomic distance, Charge distribution, Adsorption energy, Pseudocapacitance

MSC2000: 

  • O646