Facile electrodeposition of 3D concentration-gradient Ni-Co hydroxide nanostructures on nickel foam as high performance electrodes for asymmetric supercapacitors

作     者：Mingyang Yang Hua Cheng Yingying Gu Zhifang Sun Jing Hu Lujie Cao Fucong Lv Minchan Li Wenxi Wang Zhenyu Wang Shaofei Wu Hongtao Liu Zhouguang Lu 

作者机构：Department of Materials Science and Engineering South University of Science and Technology of China Shenzhen 518055 China College of Chemistry and Chemical Engineering Central South University Changsha 410083 China 

出 版 物：《Nano Research》 (纳米研究（英文版）)

年 卷 期：2015年第8卷第8期

页      面：2744-2754页

核心收录：

学科分类：081702[工学-化学工艺] 0808[工学-电气工程] 08[工学] 0817[工学-化学工程与技术] 

基　　金：This work was supported by the National Natural Science Foundation of China (No. 21001117)  the Shenzhen Peacock Plan (No. KQCX20140522150815065)  and the Starting-Up Funds of South University of Science and Technology of China (SUSTC) through the Talent Plan of the Shenzhen Government. H. T. L. acknowledges the support from a Key Project of the Hunan Provincial Science and Technology Plan (No. 2014FJ2007) 

主　　题：electrodeposition concentration-gradient nickel cobalt hydroxides supercapacitors 

摘      要：Novel three-dimensional （3D） concentration-gradient Ni-Co hydroxide nanostructures （3DCGNC） have been directly grown on nickel foam by a facile stepwise electrochemical deposition method and intensively investigated as binder- and conductor-free electrode for supercapacitors. Based on a three- electrode electrochemical characterization technique, the obtained 3DCGNC electrodes demonstrated a high specific capacitance of 1,760 F·g^-1 and a remarkable rate capability whereby more than 62.5% capacitance was retained when the current density was raised from 1 to 100 A·g^-1. More importantly, asymmetric supercapacitors were assembled by using the obtained 3DCGNC as the cathode and Ketjenblack as a conventional activated carbon anode. The fabricated asymmetric supercapacitors exhibited very promising electrochemical performances with an excellent combination of high energy density of 103.0 Wh·kg^-1 at a power density of 3.0 kW·kg^-1, and excellent rate capability-energy densities of about 70.4 and 26.0 Wh·kg^-1 were achieved when the average power densities were increased to 26.2 and 133.4 kW·kg^-1, respectively. Moreover, an extremely stable cycling life with only 2.7% capacitance loss after 20,000 cycles at a current density of 5 A·g^-1 was achieved, which compares very well with the traditional doublelayer supercapacitors.