Liu Fanggang, Wang Xiaobing, Hao Jin, Han Shuang, Lian Jianshe, Jiang Qing
Key Laboratory of Automobile Materials, Ministry of Education, and Department of Materials Science and Engineering, Jilin University, Changchun, 130022, P.R. China.
Sci Rep. 2017 Dec 18;7(1):17709. doi: 10.1038/s41598-017-17899-6.
A novel NiO/Ni/RGO three-dimensional core-shell architecture consisting of Ni nanoparticles as core, NiO as shell and reduced graphene oxide (RGO) as conductivity layer, has been constructed by redox reactions with hydrothermal method and heat treatment. High density arrayed nickel nanoparticles (20 nm diameter) semi-coated by a 3 nm thick layer of NiO are evenly distributed on the surface of graphene. This elaborate design not only uses abundant NiO surfaces to provide a wealth of active sites, but also bridges electrochemical active NiO shell and graphene by Ni core to construct an interconnected 3D conductive network. Since both electrochemical activity and excellent conductivity are reserved in this Ni/NiO core-shell/graphene layer 3D structure, the as-prepared electrode material exhibits an extremely high specific capacitance (2048.3 F g at current density of 1 A g) and excellent cycle stability (77.8% capacitance retention after 10000 cycles at current density of 50 A g). The novel method presented here is easy and effective and would provide reference for the preparation of other high performance supercapacitor electrodes.
通过水热法和热处理的氧化还原反应构建了一种新型的NiO/Ni/RGO三维核壳结构，该结构以镍纳米颗粒为核，NiO为壳，还原氧化石墨烯（RGO）为导电层。直径为20nm的高密度排列镍纳米颗粒被3nm厚的NiO层半包覆，均匀分布在石墨烯表面。这种精心设计不仅利用了丰富的NiO表面提供大量活性位点，还通过Ni核将电化学活性的NiO壳与石墨烯连接起来，构建了一个相互连接的三维导电网络。由于这种Ni/NiO核壳/石墨烯层三维结构同时保留了电化学活性和优异的导电性，所制备的电极材料表现出极高的比电容（在电流密度为1A/g时为2048.3F/g）和优异的循环稳定性（在电流密度为50A/g下10000次循环后电容保持率为77.8%）。这里提出的新方法简单有效，将为制备其他高性能超级电容器电极提供参考。
