富铁硫化物阴极中的多电子,阴离子和阳离子还氧化
Charles J Hansen1, Joshua J Zak1, Andrew J Martinolich1
1Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States.
Journal of the American Chemical Society
|April 1, 2020
概括
新的富含的硫化铁阴极,Li2FeS2和LiNaFeS2,通过可逆的铁和硫氧化还原储存高电荷能力. 这些材料避免了和,在电解质中提供稳定的循环
科学领域:
- 材料科学
- 电化学
- 固态化学
背景情况:
- 传统的离子 (Li-ion) 阴极依靠金属阴离子氧化还原来储存电荷.
- 通过每种过渡金属储存多个离子来寻求更高的充电容量.
- 电池材料中的和等资源敏感元素正在逐步淘汰.
研究的目的:
- 对高容量离子电池阴极的新型丰富层状铁硫化物进行研究.
- 阐明电荷储存机制,包括离子和离子氧化还原贡献.
- 评估循环稳定性和相对于现有的正极材料的潜在优势.
主要方法:
- 合成和描述Li2FeS2和LiNaFeS2.
- 电化学测试包括充放电循环.
- 现场和操作结构和光谱分析 (例如,SK边缘光谱).
主要成果:
- Li2FeS2和LiNaFeS2可逆地储存每个配方单位≥1.5个电子.
- 电荷储存涉及可逆的Fe2+氧化和S2−离子氧化还原 (2 S2− → (S2) 2−).
- 在Li2FeS2和LiNaFeS2之间观察到明显的结构反应,影响循环稳定性.
结论:
- 富含的硫化铁为高容量,稳定的离子电池阴极提供了有前途的途径.
- 阳离子还氧化在这些材料中起着至关重要的作用.
- 开发的材料避免了关键元素,并在稳定的电化学窗口内运行,促进了机械研究.
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