Over-Reduction-Controlled Mixed-Valent Manganese Oxide with Tunable Mn2+/Mn3+ Ratio for High-Performance Asymmetric Supercapacitor with Enhanced Cycling Stability
| Autor: | Nianrui Qu, Ming Xu, Jianmin Gu, Tongtong Xu, Zhimin Niu, Jidong Wang, Zixun Fang, Desong Wang, Qing Li, Man Qi |
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| Rok vydání: | 2021 |
| Předmět: |
Supercapacitor
Materials science Reducing agent chemistry.chemical_element 02 engineering and technology Surfaces and Interfaces Manganese Conductivity 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Capacitance Redox 0104 chemical sciences Chemical engineering chemistry Electrode Electrochemistry General Materials Science 0210 nano-technology Spectroscopy Power density |
| Zdroj: | Langmuir. 37:2816-2825 |
| ISSN: | 1520-5827 0743-7463 |
| Popis: | Manganese oxides composed of various valence states Mnx+ (x = 2, 3, and 4) have attracted wide attention as promising electrode materials for asymmetric supercapacitor. However, the poor electrical conductivity limited their performance and application. Appropriate regulation content of Mnx+ in mixed-valent manganese oxide can tune the electronic structure and further improve their conductivity and performance. Herein, we prepared manganese oxides with different Mn2+/Mn3+ ratios through an over-reduction (OR) strategy for tuning the internal electron structure of mixed-valent manganese, which could make these material oxides a good platform for researching the structure-property relationships. The Mn2+/Mn3+ ratio of manganese oxide could be precisely tuned from 0.6 to 1.7 by controlling the amount of reducing agent for manipulating the redox processes, where the manganese oxide electrode with the most appropriate Mn2+/Mn3+ ratio, as 1.65 (OR4) exhibits large capacitance (274 F g-1) and the assembling asymmetric supercapacitors by combining OR4 (positive) and the commercial activated carbon (as negative) achieved large 2.0 V voltage window and high energy density of 27.7 Wh kg-1 (power density of 500 W kg-1). The cycle lifespan of the OR4//AC could keep about 92.9% after 10 000-cycle tests owing to the Jahn-Teller distortion of the Mn(III)O6 octahedron, which is more competitive compared to other work. Moreover, a red-light-emitting diode (LED) can easily be lit for 15 min by two all-solid supercapacitor devices in a series. |
| Databáze: | OpenAIRE |
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