3D Macroporous Graphene Frameworks for Supercapacitors with High Energy and Power Densities
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- 作者：Bong Gill Choi ; MinHo Yang ; Won Hi Hong ; Jang Wook Choi ; Yun Suk Huh
- 刊名：ACS Nano
- 出版年：2012
- 出版时间：May 22, 2012
- 年：2012
- 卷：6
- 期：5
- 页码：4020-4028
- 全文大小：622K
- 年卷期：v.6,no.5(May 22, 2012)
- ISSN：1936-086X
文摘
In order to develop energy storage devices with high power and energy densities, electrodes should hold well-defined pathways for efficient ionic and electronic transport. Herein, we demonstrate high-performance supercapacitors by building a three-dimensional (3D) macroporous structure that consists of chemically modified graphene (CMG). These 3D macroporous electrodes, namely, embossed-CMG (e-CMG) films, were fabricated by using polystyrene colloidal particles as a sacrificial template. Furthermore, for further capacitance boost, a thin layer of MnO2 was additionally deposited onto e-CMG. The porous graphene structure with a large surface area facilitates fast ionic transport within the electrode while preserving decent electronic conductivity and thus endows MnO2/e-CMG composite electrodes with excellent electrochemical properties such as a specific capacitance of 389 F/g at 1 A/g and 97.7% capacitance retention upon a current increase to 35 A/g. Moreover, when the MnO2/e-CMG composite electrode was asymmetrically assembled with an e-CMG electrode, the assembled full cell shows remarkable cell performance: energy density of 44 Wh/kg, power density of 25 kW/kg, and excellent cycle life.