氧化镍包覆石墨的制备及其超级电容性能研究

Preparation of Graphite Coated with Nickel Oxide and Its Supercapacitor Performance

碳基电极材料和过渡金属氧化物材料作为超级电容器的常见电极材料在性能上各有千秋,以石墨为基体,采用溶胶凝胶法将金属NiO包覆在石墨表面形成新的电容电极复合材料。采用N2吸附脱附分析仪、X射线衍射仪、电化学工作站和充放电测试仪表征石墨及NiO包覆石墨的结构和电化学性能。实验结果表明:NiO包覆有效提升了石墨基体材料的组织结构和电化学性能。材料比表面积显著增加,孔容也随之增大;NiO包覆表现出明显的赝电容特征,NiO包覆石墨在0. 2 A/g首次放电比容量为203. 13 F/g,在5 A/g的电流密度下放电比容量达到130. 45 F/g,石墨的放电比容量为90. 02 F/g,NiO包覆后石墨的比容量提升了45%。石墨和NiO包覆层具有协同作用,NiO包覆降低了石墨的阻抗,并提升了循环性能。

Carbon-based electrode materials and transition metal oxide materials have their properties as the common electrode materials for supercapacitors. In this paper, graphite was used as the matrix, and metal nickel oxide was coated on the graphite surface with a sol-gel method to form a new capacitor electrode composite. The structure and electrochemical properties of graphite and graphite coated with nickel oxide were characterized by N2 adsorption-desolption analyzer, X-ray diffractometer, electrochemical workstation, and charging and discharging tester. The experimental results showed that the nickel oxide coating could effectively improve the microstructure and electrochemical properties of the graphite matrix. The specific surface area of the material significantly increased, and the pore volume also increased. The nickel oxide coating exhibited obvious characteristics of tantalum capacitance. In the first discharge, the specific capacity of graphite coated with nickel oxide at the current density of 0. 2 A/g was 203. 13 F/g . At the current density of 5 A/g, the discharging specific capacity of graphite coated with nickel oxide was 130. 45 F/g, and graphite was only 90.02 F/g, and the specific capacity of graphite after nickel oxide coating increased by 45%. There is a synergistic effect between the graphite and nickel oxide coating, and the nickel oxide coating can reduce the impedance of the graphite and improve the cycle performance.