Nitrogen-doped reduced graphene oxide-Ni(OH)2-built 3D flower composite with easy hydrothermal process and excellent electrochemical performance

An advanced supercapacitor electrode material based on nitrogen-doped reduced graphene oxide and nickel hydroxide (N-RGO&Ni(OH)(2)) is prepared via an easy two-step hydrothermal method. With the enhanced electrochemical activity upon nitrogen doping and the unique three dimensional flower-like structure, the synthesized N-RGO&Ni(OH)(2) shows much better electrochemical performance than the sample without nitrogen doping. The results indicate that N-RGO&Ni(OH)(2) owns high capacitance, excellent rate capability, good cycle life, etc. Specifically, the N-RGO&Ni(OH)(2) electrode exhibits specific capacitance as high as 1382 F/g at current density of 6 A/g in 6 M KOH aqueous electrolyte. When the current density increases from 6 to 25 A/g, 60.06% of the initial capacitance is approximately retained. In addition, the electrode exhibits good cycling stability with the capacitance retention of 99.75% is attained after 2400 cycle tests at a scan rate of 100 mV/s. The synthesis developed in this work offers a promising approach for easy preparation of supercapacitor electrode material with superior electrochemical property. (C) 2014 Elsevier Ltd. All rights reserved.