MnO2 nanoflakes/hierarchical porous carbon nanocomposites for high-performance supercapacitor electrodes
MnO2 nanoflakes/hierarchical porous carbon nanocomposites for high-performance supercapacitor electrodes
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用于高性能超级电容器电极的MnO2纳米片/分级多孔碳纳米复合材料
DOI：
10.1016/j.electacta.2015.02.218
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发表时间：
2015-05-01
影响因子：
6.6
通讯作者：
Li, Chunzhong
中科院分区：
文献类型：
--
作者：
Li, Huailong;Jiang, Lixue;Li, Chunzhong
采用两步氧化还原法合成了MnO 2纳米片/分级多孔碳球（HPC）纳米复合材料。外部MnO 2纳米片的厚度接近10 nm的沉积在表面的HPC导致形成的层次结构的复合材料，而内部MnO 2层稳定的MnO 2纳米片和HPC之间的相互作用。在去除介孔SiO2模板剂后，所得复合材料仍保持多孔结构，并表现出较高的比表面积。通过改变Mn（NO3）（2）和KMnO 4的初始含量可以很容易地实现复合材料的形貌控制。通过循环伏安法、恒流充放电和电化学阻抗谱技术评价了复合材料作为超级电容器电极材料的电化学性能。当MnO 2含量为75wt%时，MnO 2纳米片/HPC复合材料在高扫描速率或电流密度下具有最高的比电容（20 mV s（1）时为417.2 F g（1），1 A g（1）时为326.9 F g（1），和非凡的循环稳定性（在100 mV s（1）的扫描速率下10000次循环后，电容保持率略高于100%），其上级其他报道的MnO 2/碳复合材料。结果表明，合理设计和合成具有最大电化学活性中心的MnO 2/多孔碳复合电极材料是进一步提高其电化学性能的重要途径。(C)2015爱思唯尔有限公司版权所有。
A facile strategy is developed for the synthesis of MnO2 nanoflakes/hierarchical porous carbon spheres (HPCs) nanocomposites via a two-step redox process. The external MnO2 nanoflakes with thickness of similar to 10 nm deposited on the surface of the HPCs result in the formation of hierarchical architecture of the composites, while the internal MnO2 layer stabilizes the interaction between MnO2 nanoflakes and HPCs. The resultant composites still retain porous structure after removal of mesoporous SiO2 template and exhibit relatively high specific surface area. The morphology control of the composites can be easily achieved by varying the initial content of Mn(NO3)(2) and KMnO4. Electrochemical performance of the composites as supercapacitor electrode materials was evaluated by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy techniques. The MnO2 nanoflakes/HPCs composite with 75 wt% MnO2 possesses the highest specific capacitance at a high scan rate or current density (417.2 F g (1) at 20 mV s (1) and 326.9 F g (1) at 1 A g (1), respectively) and extraordinary cycling stability (slightly over 100% capacitance retention after 10000 cycles at a scan rate of 100 mV s (1)), which are superior to other reported MnO2/carbon composites. The results suggest that rational design and synthesis of MnO2/porous carbon composite electrode materials with maximum electrochemical active sites is important to further improve their electrochemical performance. (C) 2015 Elsevier Ltd. All rights reserved.