Incorporation of Manganese Dioxide within Ultraporous Activated Graphene for High-Performance Electrochemical Capacitors

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• 作者：Xin Zhao ; Lili Zhang ; Shanthi Murali ; Meryl D. Stoller ; Qinghua Zhang ; Yanwu Zhu ; Rodney S. Ruoff
• 刊名：ACS Nano
• 出版年：2012
• 出版时间：June 26, 2012
• 年：2012
• 卷：6
• 期：6
• 页码：5404-5412
• 全文大小：549K
• 年卷期：v.6,no.6(June 26, 2012)
• ISSN：1936-086X

文摘

Manganese dioxide (MnO₂) particles 2鈥? nm in size were deposited onto a porous 鈥渁ctivated microwave expanded graphite oxide鈥?(aMEGO) carbon scaffold via a self-controlled redox process. Symmetric electrochemical capacitors were fabricated that yielded a specific capacitance of 256 F/g (volumetric: 640 F/cm³) and a capacitance retention of 87.7% after 1000 cycles in 1 M H₂SO₄; when normalized to MnO₂, the specific capacitance was 850 F/g. Asymmetric electrochemical capacitors were also fabricated with aMEGO/MnO₂ as the positive electrode and aMEGO as the negative electrode and had a power density of 32.3 kW/kg (for an energy density of 20.8 Wh/kg), an energy density of 24.3 Wh/kg (for a power density of 24.5 kW/kg), and a capacitance retention of 80.5% over 5000 cycles.

Keywords:

aMEGO; MnO₂; composites; asymmetric; electrochemical capacitors