Wang Ziya, Wang Fengping, Li Yan, Hu Jianlin, Lu Yanzhen, Xu Mei
Department of Physics, School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, PR China.
Nanoscale. 2016 Apr 7;8(13):7309-17. doi: 10.1039/c5nr08857g.
Structure designing and morphology control can lead to high performance pseudocapacitive materials for supercapacitors. In this work, we have designed interlinked multiphase Fe-doped MnO2 nanostructures (α-MnO2/R-MnO2/ε-MnO2) to enhance the electrochemical properties by a facile method. These hierarchical hollow microspheres assembled by interconnected nanoflakes, and with plenty of porous nanorods radiating from the spherical shells were hydrothermally obtained. The supercapacitor electrode prepared from the unique construction exhibits outstanding specific capacitance of 267.0 F g(-1) even under a high mass loading (∼5 mg cm(-2)). Obviously improved performances compared to pure MnO2 are also demonstrated with a good rate capability, high energy density (1.30 mW h cm(-3)) and excellent cycling stability of 100% capacitance retention after 2000 cycles at 2 A g(-1). The synergistic effects of alternative crystal structures, appropriate crystallinity and optimal morphology are identified to be responsible for the observations. This rational multiphase composite strategy provides a promising idea for materials scientists to design and prepare scalable electrode materials for energy storage devices.
结构设计和形态控制能够制备出用于超级电容器的高性能赝电容材料。在本工作中，我们通过一种简便的方法设计了相互连接的多相铁掺杂二氧化锰纳米结构（α-MnO₂/R-MnO₂/ε-MnO₂）以提升其电化学性能。通过水热法获得了由相互连接的纳米片组装而成的分层空心微球，且从球壳辐射出大量多孔纳米棒。由这种独特结构制备的超级电容器电极即使在高质量负载（约5 mg cm⁻²）下仍表现出267.0 F g⁻¹的出色比电容。与纯MnO₂相比，其性能也有显著提升，具有良好的倍率性能、高能量密度（1.30 mW h cm⁻³）以及在2 A g⁻¹下循环2000次后电容保持率达100%的优异循环稳定性。研究发现，交替晶体结构、适当的结晶度和最佳形态的协同效应是这些优异性能的原因。这种合理的多相复合策略为材料科学家设计和制备用于储能设备的可扩展电极材料提供了一个有前景的思路。
