Preparation And Supercapacitive Performance Of Nitrogen-Doped Graphene/Nickel Hydroxide

Supercapacitor due to its excellent power density has been widespread concern in recent years. Graphene is an ideal supercapacitor electrode material, however, it is easy to aggregate bulk when preparation and using, resulting in electrochemical performance degradation. As a supercapacitor electrode, although Nickel hydroxide has a high theoretical specific capacitance, electrochemical performance degradation results from its close packing between the sheet and volume expansion of the charge-discharge process. Preparation of nitrogen-doped graphene sheet can optimize the lamellar structure of graphene by adjustment of the electronic structure of graphene. In order to achieve good electrochemical performance, nitrogen-doped graphene was added to adjust the distribution of nickel hydroxide’s sheets. Nitrogen-doped graphene/nickel hydroxide composite was prepared by co-precipitation method.1> Using ethylene diamine as a nitrogen-doped agent at 180℃ 12h hydrothermal conditions for preparing nitrogen-doped graphene, XPS analysis showed nitrogen-doped reached 10.4%. The electrochemical properties and structure of different proportion of nitrogen-doped graphene/nickel hydroxide composite and the relationships of different nitrogen-doped graphene/nickel hydroxide between structure and properties was investigatived.We found the composites added 50mg nitrogen-doped graphene reached 1334.0F·g-1 (0.5A-g-1), whose nitrogen content is 1.51% and that its resistivity is only 0.54Ω, Thus its conductivity is enhanced;2, Ethylenediamine as a nitrogen-doped agent, at 80℃,24h water bath for preparing nitrogen-doped graphene, nitrogen-doped content reached 3.15%. We investigated the microstructure and chemical status of different proportion of nitrogen-doped graphene/nickel hydroxide composite, made a thorough study of its electrochemical properties and discussed performance changes of different ratio of nitrogen-doped graphene/nickel hydroxide.The result showed composites’ nitrogen content is 1.08% by adding 50mg of nitrogen-doped graphene and specific capacitance reaches 1661.3F·g-1 (0.5A·g-1).At 10 A·g-1 current density, after circulation 2000 times specific capacitance decreased from 1160.0 F·g-1 to 814.3F g-1, retains70.2% of the initial specific capacitance value While its inherent resistance is only 0.8794Ω, conductivity is improved greatly thereby affecting its electrochemical properties;3, Urea as a nitrogen-doped agent, at 160℃,3h prepared graphene-doped different ratios of nitrogen, XPS analysis showed that nitrogen content is within the range of 6.18%-9.46% And by studying the electrochemical properties of nitrogen-doped graphene/nickel hydroxide composite, we found specific capacitance of 1:40 nitrogen-doped graphene/nickel hydroxide composites can reaches 1137.5 F·g-1 (0.5A ·g-1).