Le Kai, Wang Zhou, Wang Fenglong, Wang Qi, Shao Qian, Murugadoss Vignesh, Wu Shide, Liu Wei, Liu Jiurong, Gao Qiang, Guo Zhanhu
Institute of Crystal Materials, Shandong University, Jinan, Shandong 250100, China.
Dalton Trans. 2019 Apr 16;48(16):5193-5202. doi: 10.1039/c9dt00615j.
Nanocomposites with a well-defined sandwich-like nanostructure were prepared via in situ growing NiCo-layered double hydroxide nanosheets with tunable Ni/Co ratios on reduced graphene oxide (rGO). Electrochemical impedance spectra and N2 adsorption/desorption isotherms confirmed that these sandwich nanostructures effectively promoted charge transport and enlarged the specific surface area. The nanocomposites with Ni : Co = 2 : 1 exhibited a maximum specific capacitance of 2130 F g-1 at 2 A g-1, excellent rate capability (72.7% retention at 15 A g-1), and cycling stability. Asymmetric supercapacitors were assembled with these nanocomposite cathodes and rGO as a negative electrode (anode), and demonstrated an energy density of 34.5 W h kg-1 at a power density of 772 W kg-1, while maintaining a capacity retention of 86.7% after 10 000 cycles at 5 A g-1. The robust electrochemical properties indicate the composites as promising electrodes for electrochemical energy storage devices.
通过在还原氧化石墨烯（rGO）上原位生长具有可调Ni/Co比的NiCo层状双氢氧化物纳米片，制备了具有明确三明治状纳米结构的纳米复合材料。电化学阻抗谱和N2吸附/解吸等温线证实，这些三明治纳米结构有效地促进了电荷传输并扩大了比表面积。Ni : Co = 2 : 1的纳米复合材料在2 A g-1下表现出2130 F g-1的最大比电容、优异的倍率性能（在15 A g-1下保持72.7%）和循环稳定性。以这些纳米复合阴极和rGO作为负极（阳极）组装了不对称超级电容器，在功率密度为772 W kg-1时表现出34.5 W h kg-1的能量密度，同时在5 A g-1下循环10000次后容量保持率为86.7%。这些强大的电化学性能表明该复合材料是电化学储能装置的有前景的电极材料。
