Freestanding Three-Dimensional Graphene/MnO2 Composite Networks As Ultralight and Flexible Supercapacitor Electrodes
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- 作者：Yongmin He ; Wanjun Chen ; Xiaodong Li ; Zhenxing Zhang ; Jiecai Fu ; Changhui Zhao ; Erqing Xie
- 刊名：ACS Nano
- 出版年：2013
- 出版时间：January 22, 2013
- 年：2013
- 卷：7
- 期：1
- 页码：174-182
- 全文大小：628K
- 年卷期：v.7,no.1(January 22, 2013)
- ISSN：1936-086X
文摘
A lightweight, flexible, and highly efficient energy management strategy is needed for flexible energy-storage devices to meet a rapidly growing demand. Graphene-based flexible supercapacitors are one of the most promising candidates because of their intriguing features. In this report, we describe the use of freestanding, lightweight (0.75 mg/cm2), ultrathin (<200 渭m), highly conductive (55 S/cm), and flexible three-dimensional (3D) graphene networks, loaded with MnO2 by electrodeposition, as the electrodes of a flexible supercapacitor. It was found that the 3D graphene networks showed an ideal supporter for active materials and permitted a large MnO2 mass loading of 9.8 mg/cm2 (92.9% of the mass of the entire electrode), leading to a high area capacitance of 1.42 F/cm2 at a scan rate of 2 mV/s. With a view to practical applications, we have further optimized the MnO2 content with respect to the entire electrode and achieved a maximum specific capacitance of 130 F/g. In addition, we have also explored the excellent electrochemical performance of a symmetrical supercapacitor (of weight less than 10 mg and thickness 0.8 mm) consisting of a sandwich structure of two pieces of 3D graphene/MnO2 composite network separated by a membrane and encapsulated in polyethylene terephthalate (PET) membranes. This research might provide a method for flexible, lightweight, high-performance, low-cost, and environmentally friendly materials used in energy conversion and storage systems for the effective use of renewable energy.