Ni(OH)_2/RGO复合材料的化学沉淀-回流法制备和放电性能

Chemical Precipitation-reflux Synthesis and Discharge Performance of Composite of Nickel Hydroxide/Reduced Graphene Oxide

以氧化石墨(GO)和NiSO_4·6H_2O为前驱体,氨水为沉淀剂,用化学沉淀-回流法制备Ni(OH)_2/还原氧化石墨烯(RGO)复合材料,用XRD、SEM表征材料的结构和表面微观形貌,用循环伏安(CV)、恒电流充放电和电化学阻抗(EIS)测试电极材料的电化学性能,研究了GO:Ni(OH)_2质量比和氨水浓度对复合材料结构、形貌和电化学性能的影响。结果表明:所制备的β-Ni(OH)_2/RGO复合材料为Ni(OH)_2纳米片与RGO片相互插层的结构,当氨水的浓度为3 mol/L,GO:Ni(OH)_2=1:8(质量比)时复合电极材料在0.2C的放电比容量高达334.9 mAh/g,5C的放电比容量为260.2 mAh/g,保持在β-Ni(OH)_2理论比容量的90%,表现出良好的倍率性能和循环性能。

Composite of nickel hydroxide/reduced graphene oxide（Ni（OH）_2/RGO） was synthesized by facile chemical precipitation-reflux method with graphite oxide and nickel sulfate hexahydrate as precursors and ammonium hydroxide as the precipitator. The surface morphology and microscopic structures of the composite were characterized by X-ray diffraction（XRD） and scan electron microscopy（SEM）. The electrochemical performance of the composite was assessed by cyclic voltammetry（CV）, galvanostatic charge/discharge and electrochemical impedance spectroscopy（EIS）. The influence of different mass ratio of graphite oxide to nickel hydroxide（GO： Ni（OH）_2） and the concentration of ammonium hydroxide on structures, morphologies, and electrochemical properties of the composite was investigated.The results show that the synthesized composite of β-Ni（OH）_2/RGO has mutually inserted structure. The composite of β-Ni（OH）_2/RGO exhibits high electrochemical performance of 334.9 mAh/g at 0.2C rate and260.2 m Ah/g at 5C rate when the concentration of ammonium hydroxide is 3 mol/L and the mass ratio of GO：Ni（OH）_2is 1：8, while the product can still maintain 90% of the theoretical specific capacity of β-Ni（OH）_2.It displays that this electrode material has excellent electrochemical performance with excellent rate capability.