Enhanced Cycleability of Amorphous MnO₂ by Covering on α-MnO₂ Needles in an Electrochemical Capacitor.
Enhanced Cycleability of Amorphous MnO₂ by Covering on α-MnO₂ Needles in an Electrochemical Capacitor.
复制标题
通过覆盖电化学电容器中的α-MnO2 针增强非晶态MnO2 的循环性能
DOI：
10.3390/ma10090988
复制
发表时间：
2017-08-24
期刊：
影响因子：
--
通讯作者：
Wang R
中科院分区：
文献类型：
--
作者：
Liu Q;Ji S;Yang J;Wang H;Pollet BG;Wang R
通过两步水相反应方法开发了同质异形MnO2@MnO2核壳纳米结构。扫描电子显微镜、透射电子显微镜、X射线衍射和N2吸附-解吸等温线实验的数据分析表明，这种独特的结构由非晶MnO2纳米片的多孔层组成，该多孔层生长在α-MnO2纳米针的表面上。循环伏安实验表明，MnO2@MnO2电容器电极的双层充电和法拉第赝电容在0.1 A·g−1电流密度下实现了150.3 F·g−1的比电容。对所制备的 MnO2@MnO2 样品进行的长循环寿命实验表明，在 2 A·g−1 的电流密度下循环 5000 次后，其保留率接近 99.3%。发现该保留值明显高于非晶态 MnO2 基电容器电极报道的保留值。研究还发现，MnO2@MnO2的显着循环性能归因于α-MnO2纳米针核和外部非晶MnO2层的支撑作用。
An allomorph MnO2@MnO2 core-shell nanostructure was developed via a two-step aqueous reaction method. The data analysis of Scanning Electron Microscopy, Transmission Electron Microscopy, X-Ray Diffraction and N2 adsorption-desorption isotherms experiments indicated that this unique architecture consisted of a porous layer of amorphous-MnO2 nano-sheets which were well grown onto the surface of α-MnO2 nano-needles. Cyclic voltammetry experiments revealed that the double-layer charging and Faradaic pseudo-capacity of the MnO2@MnO2 capacitor electrode contributed to a specific capacitance of 150.3 F·g−1 at a current density of 0.1 A·g−1. Long cycle life experiments on the as-prepared MnO2@MnO2 sample showed nearly a 99.3% retention after 5000 cycles at a current density of 2 A·g−1. This retention value was found to be significantly higher than those reported for amorphous MnO2-based capacitor electrodes. It was also found that the remarkable cycleability of the MnO2@MnO2 was due to the supporting role of α-MnO2 nano-needle core and the outer amorphous MnO2 layer.