混合氨-碱沉淀剂制备Ni(OH)_2/还原氧化石墨烯复合材料及其电化学性能

利用简单易行的化学沉淀-回流法制备了Ni(OH)_2/还原氧化石墨烯(RGO)复合材料,研究了不同混合氨-碱沉淀剂对复合材料电化学性能的影响。采用XRD、拉曼光谱(Raman)和SEM表征Ni(OH)_2/RGO复合材料的微观结构和形貌。当以NH_3·H_2O-NaOH作为沉淀剂时,Ni(OH)_2/RGO复合材料中β-Ni(OH)_2纳米片均匀分散在石墨烯片层之间,形成相互插层结构。利用循环伏安(CV)、恒电流充放电(GCD)和电化学交流阻抗(EIS)测试了复合电极材料的电化学性能。研究结果表明:放电倍率为0.2C时,Ni(OH)_2/RGO复合电极材料的放电比容量达到344.8mAh/g,比β-Ni(OH)2的放电比容量高出约29%;5C时放电比容量为274.5mAh/g,经过50个循环,容量保持率为98.8%,呈现出良好的倍率性能和循环性能。

Ammonia-alkali mixed precipitant route for preparation of Ni(OH)2/reduced graphene oxide composites and electrochemical performance

Nickel hydroxide/reduced graphene oxide (Ni(OH)2/RGO) composites were synthesized by simple and practicable chemical precipitation-reflux method.The influence of different ammonia-alkali mixed precipitant on electrochemical performance of composite materials was researched.The microstructure and morphology of the Ni(OH)2/RGO composites were characterized by XRD, Raman spectra and SEM.The synthesized Ni(OH)2/RGO composite shows that β-Ni(OH)2 nano sheets are homogeneously dispersed and inserted into RGO sheets, thus mutually inserted structure is formed using ammonium hydroxide-sodium hydroxide as precipitant.The electrochemical characteristics of composite electrode materials were tested by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS).The results show that the prepared Ni(OH)2/RGO composite exhibits a high discharge specific capacity of 344.8 mAh/g at 0.2 C rate, and is 29% higher than the specific capacity of β-Ni(OH)2.The discharge specific capacity of the β-Ni(OH)2/RGO composite is 274.5 mAh/g at 5 C rate.Moreover, 98.8% of the initial specific capacity of the composite is maintained after 50 cycle test.Ni(OH)2/RGO composite displays a better rate capability and cycle performance as electrode material.