Stabilizing fluorine to achieve high-voltage and ultra-stable Na3V2(PO4)2F3 cathode for sodium ion batteries
| Autor: | Lan-Fang Que, Xu-Lei Sui, Zhen-Bo Wang, Yun-Shan Jiang, Xiang-hui Meng, Lei Zhao, Liang Deng, Fu-Da Yu, Yang Xia |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
Renewable Energy Sustainability and the Environment business.industry Sodium Kinetics chemistry.chemical_element High voltage 02 engineering and technology Electronic structure Atmospheric temperature range 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Cathode 0104 chemical sciences law.invention chemistry law Fluorine Optoelectronics General Materials Science Electrical and Electronic Engineering 0210 nano-technology business Voltage |
| Zdroj: | Nano Energy. 82:105659 |
| ISSN: | 2211-2855 |
| DOI: | 10.1016/j.nanoen.2020.105659 |
| Popis: | Na3V2(PO4)2F3 is a promising cathode candidate for sodium ion batteries due to its high working voltage. However, an “unknown” low-voltage plateau around ~3.3 V lowers its operating voltage and puzzles researchers. Herein, the reasons for its appearance are explored. It is found that the formation of the low-voltage plateau originates from the extra-generated [VO6] induced by the fluorine loss during the synthesis. To enable better performance, a feasible strategy of stabilizing fluorine is proposed to eliminate the low-voltage plateau. It is demonstrated that this strategy can effectively guarantee the existence of fluorine and modulate the local electronic structure of V to maintain [VO4F2] in Na3V2(PO4)2F3 phase, thus eliminating the undesirable plateau and achieving an operating-voltage increase of ~100 mV. Moreover, the enhanced structural stability and kinetics of the optimized Na3V2(PO4)2F3 cathode are confirmed by in-situ XRD. As expected, the Na3V2(PO4)2F3 cathode delivers higher energy density (446.4 Wh kg−1), better rate capability and longer cycling performance (89.2%@30 C after 1000 cycles). Furthermore, its excellent adaptability to wide temperature range (−25 °C–55 °C) and strong competence in Na3V2(PO4)2F3||hard carbon full-cell are verified. These excellent properties further qualify Na3V2(PO4)2F3 as a competitive cathode for sodium ion batteries. |
| Databáze: | OpenAIRE |
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