Cobalt-Doped MnO2 Hierarchical Yolk–Shell Spheres with Improved Supercapacitive Performance

• Published in: Journal of physical chemistry. C
• Main Authors: Tang, Chuan-Lin, Wei, Xiao, Jiang, Yan-Mei, Wu, Xue-Yan, Han, Li−Na, Wang, Kai-Xue, Chen, Jie-Sheng
• Format: Journal Article
• Language: English
• Published: American Chemical Society 23.04.2015
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp512795g

Cobalt-doped MnO2 with a hierarchical yolk–shell spherical structure has been prepared by a light-assisted method. The hierarchical spheres obtained are characterized by X-ray diffraction, nitrogen adsorption–desorption, and electron microscopy analyses. The supercapacitive performance of the material is evaluated by cyclic voltammetry and galvanostatic charge/discharge measurements. A specific capacitance of 350 F g–1 is achieved at a current density of 0.1 A g–1 for the spheres with a Co/Mn ratio of 0.5%, much higher than that of the undoped MnO2 with a similar hierarchical spherical structure, which is approximately 168 F g–1. A specific capacitance of 196 F g–1 is still retained after being charged/discharged at a current density of 2.0 A g–1 for 1000 cycles, demonstrating good cycling stability. Over 90% of the initial specific capacitance was retained, exhibiting excellent capacitance retention ability.