Capacity improvement of the carbon-based electrochemical capacitor by zigzag-edge introduced graphene
Capacity improvement of the carbon-based electrochemical capacitor by zigzag-edge introduced graphene
复制标题
DOI：
10.1016/j.apsusc.2017.09.187
复制
发表时间：
2018-01
影响因子：
6.7
通讯作者：
Naoki Tamura;T. Tomai;Nobuto Oka;I. Honma
中科院分区：
文献类型：
--
作者：
Naoki Tamura;T. Tomai;Nobuto Oka;I. Honma
石墨烯边缘的电化学性质一直备受关注。特别是锯齿形棱边由于存在中性自由基而具有较高的电化学活性。然而，由于缺乏锯齿形石墨烯的有效制备方法，锯齿形边缘的电化学性质尚未得到实验证明，并且通过控制其边缘状态来提高储能装置中的碳质材料的电容仍然是一个挑战。我们通过一个结合超临界流体中石墨烯剥离和催化纳米颗粒的各向异性蚀刻的分步方法。这种富含锯齿形边缘的石墨烯的有效生产使我们能够研究锯齿形边缘的电化学活性。通过循环伏安法，我们发现锯齿形边缘引入的石墨烯在酸性水溶液中表现出独特的氧化还原反应。此外，通过密度泛函理论（DFT）计算，锯齿形边缘引入石墨烯的独特氧化还原电位可以归因于锯齿形边缘处的质子插入/提取反应。这一发现表明石墨烯边缘修饰可以有助于碳基电化学电容器的电容的进一步增加。
The electrochemical properties of graphene edge has been attracted much attention. Especially, zigzag edge has high electrochemical activity because neutral radical exits on edge. However, due to a lack of efficient production method for zigzag graphene, the electrochemical properties of zigzag edge have not been experimentally demonstrated and the capacitance enhancement of carbonaceous materials in energy storage devices by the control in their edge states is still challenge.In this study, we fabricated zigzag-edge-rich graphene by a one-step method combining graphene exfoliation in supercritical fluid and anisotropic etching by catalytic nanoparticles. This efficient production of zigzag-edge-rich graphene allows us to investigate the electrochemical activity of zigzag edge. By cyclic voltammetry, we revealed the zigzag edge-introduced graphene exhibited unique redox reaction in aqueous acid solution. Moreover, by the calculation on the density function theory (DFT), this unique redox potential for zigzag edge-introduced graphene can be attributed to the proton-insertion/-extraction reactions at the zigzag edge. This finding indicates that the graphene edge modification can contribute to the further increase in the capacitance of the carbon-based electrochemical capacitor.