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Facile synthesis of cuboid Ni-MOF for high-performance supercapacitors

Gao, Shuwen, Sui, Yanwei, Wei, Fuxiang, Qi, Jiqiu, Meng, Qingkun, He, Yezeng
Journal of materials science 2018 v.53 no.9 pp. 6807-6818
capacitance, carbon, coordination compounds, electrodes, electrolytes, hot water treatment, nickel, porous media, potassium hydroxide, specific energy
Metal–organic frameworks (MOF) used directly in supercapacitors have attracted much attention for their special porous structure and potential high performance. Here, the Ni-MOF is fabricated by one-step facile hydrothermal method with a modification of mixed solution with DMF and water instead of pure DMF. After characterization, the Ni-MOF exhibits loosely stacked layer-cuboid structure with abundant mesoporous, which is beneficial for the charge transfer and ion transport for supercapacitors. In the three-electrode system, this Ni-MOF serving as working electrode shows remarkable specific capacitance of 804 Fg⁻¹ at 1 Ag⁻¹, excellent rate capacitance of 534 Fg⁻¹ at 10 Ag⁻¹, and with 302 Fg⁻¹ retention after 5000 cycles, when measured in 2 M KOH electrolyte solution. To make a further research into the practical utility of the Ni-MOF, the Ni-MOF//AC asymmetrical supercapacitor device is assembled with the Ni-MOF and active carbon acted as positive and negative electrode materials, respectively. This device exhibits high specific energy of 31.5 Wh kg⁻¹, at specific power of 800 W kg⁻¹. All these results demonstrate that this Ni-MOF is a kind of promising electrode material for high-performance supercapacitors.