Hydrothermal synthesis of Ni@C core-shell composites with high capacitance
详细信息 查看全文
- 作者：Lengyuan Niu ; Zhangpeng Li ; Jinfeng Sun ; Zengjie Fan ; Ye Xu ; Peiwei Gong ; Shengrong Yang ; Jinqing Wang
- 关键词：Nickel nanoparticles ; Carbon coating ; Composite ; Supercapacitor
- 刊名：Journal of Alloys and Compounds
- 出版年：2013
- 出版时间：25 October, 2013
- 年：2013
- 卷：575
- 期：Complete
- 页码：152-157
- 全文大小：1820 K
文摘
Ni@C core-shell composites with different crystal structures were synthesized by chemical reduction of nickel (II) acetate tetrahydrate using ethylene glycol as reducing agent and sodium citrate as a carbon source, followed by annealing at different temperatures in the nitrogen atmosphere. X-ray diffraction analysis indicates that the crystal structure of Ni is dependent on the annealing temperatures. At 250 ¡ãC, both face-centered cubic and hexagonal closed-packed (hcp) phases of Ni coexist in the Ni@C composites, whereas there is only hcp phase Ni observed as being annealed at 300 ¡ãC. The synthesized Ni@C composites were applied as electrode materials for supercapacitors and exhibited superior electrochemical performances. Especially, the electrode annealed at 250 ¡ãC displays the highest specific capacitance of 530 F g?1 in 2 M KOH solution at a current density of 1 A g?1. In addition, the synthesized Ni@C composite electrodes also show excellent rate capability and cycle stability, presenting the promising potential as electrode material for supercapacitors.