Three-Dimensional Expanded Graphene鈥揗etal Oxide Film via Solid-State Microwave Irradiation for Aqueous Asymmetric Supercapacitors

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• 作者：MinHo Yang ; Kyoung G. Lee ; Seok Jae Lee ; Sang Bok Lee ; Young-Kyu Han ; Bong Gill Choi
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：October 14, 2015
• 年：2015
• 卷：7
• 期：40
• 页码：22364-22371
• 全文大小：502K
• ISSN：1944-8252

文摘

Carbon-based electrochemical double-layer capacitors and pseudocapacitors, consisting of a symmetric configuration of electrodes, can deliver much higher power densities than batteries, but they suffer from low energy densities. Herein, we report the development of high energy and power density supercapacitors using an asymmetric configuration of Fe₂O₃ and MnO₂ nanoparticles incorporated into 3D macroporous graphene film electrodes that can be operated in a safe and low-cost aqueous electrolyte. The gap in working potential windows of Fe₂O₃ and MnO₂ enables the stable expansion of the cell voltage up to 1.8 V, which is responsible for the high energy density (41.7 Wh kg^鈥?). We employ a household microwave oven to simultaneously create conductivity, porosity, and the deposition of metal oxides on graphene films toward 3D hybrid architectures, which lead to a high power density (13.5 kW kg^鈥?). Such high energy and power densities are maintained for over 5000 cycles, even during cycling at a high current density of 16.9 A g^鈥?.