Direct Reduction of Graphene Oxide by Ni Foam as a High-Capacitance Supercapacitor Electrode

详细信息    查看全文

• 作者：Jing Yang ; Enwei Zhang ; Xiaofeng Li ; Yunhua Yu ; Jin Qu ; Zhong-Zhen Yu
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：January 27, 2016
• 年：2016
• 卷：8
• 期：3
• 页码：2297-2305
• 全文大小：696K
• ISSN：1944-8252

文摘

Three dimensional reduced graphene oxide (RGO)/Ni foam composites are prepared by a facile approach without using harmful reducing agents. Graphene oxide is reduced by Ni foam directly in its aqueous suspension at pH 2 at room temperature, and the resultant RGO sheets simultaneously assemble around the pillars of the Ni foam. The RGO/Ni foam composite is used as a binder-free supercapacitor electrode and exhibits high electrochemical properties. Its areal capacitance is easily tuned by varying the reduction time for different RGO loadings. When the reduction time increases from 3 to 15 days, the areal capacitance of the composite increases from 26.0 to 136.8 mF cm^–2 at 0.5 mA cm^–2. Temperature is proven to be a key factor in influencing the reduction efficiency. The composite prepared by 5 h reduction at 70 °C exhibits even better electrochemical properties than its counterpart prepared by 15 day reduction at ambient temperature. The 5 h RGO/Ni foam composite shows an areal capacitance of 206.7 mF cm^–2 at 0.5 mA cm^–2 and good rate performance and cycling stability with areal capacitance retention of 97.4% after 10000 cycles at 3 mA cm^–2. Further extending the reduction time to 9 h at 70 °C, the composite shows a high areal capacitance of 323 mF cm^–2 at 0.5 mA cm^–2. Moreover, the good rate performance and cycling stability are still maintained.