A novel MnO2 petal nanosheet@carbon sphere core-shell structure was successfully fabricated by adjusting the quantity of the KMnO4 precursor employed during the in situ growth of MnO2 on the surface of carbon spheres via a facile hydrothermal method. In the presence of low KMnO4 contents, only MnOOH was generated. In contrast, upon increasing the quantity of KMnO4, δ-MnO2 nanorods and petal nanosheets were obtained, thereby allowing the formation of the core-shell structured δ-MnO2 petal nanosheet@carbon sphere composites. However, beyond a certain point, further increases in the KMnO4 content were unfavorable. Although, prepared MnO2/carbon sphere composites of different morphologies can be used for supercapacitors (SCs) electrode materials, we found that the core-shell structured MnO2 petal nanosheet@carbon sphere composites exhibited the optimal capacitance performances in all the composites. These composites exhibited an excellent specific capacitance of 231 F⋅g−1 under a current density of 0.5 A⋅g−1. Furthermore, they also demonstrated an impressive cycling stability. Indeed, after 1,000 cycles at 10 A⋅g−1, the MnO2 petal nanosheet@carbon spheres exhibited 96% of their initial capacitance in a 1 M Na2SO4 aqueous electrolyte. The synergistic effect between δ-MnO2 and the porous carbon spheres in the unique core-shell structured is responsible for the excellent cycle life.
|Original language||English (US)|
|Number of pages||7|
|State||Published - Aug 31 2018|
Bibliographical noteFunding Information:
This work was supported by the National Natural Science Foundation of China (No. 21606058 and No. 21206139).
© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
- carbon sphere
- core-shell structure
ASJC Scopus subject areas