电子移位使基单溶剂电解质用于金属电池成为可能
Muhammad Mominur Rahman1, Enyuan Hu1
1Chemistry Division, Brookhaven National Laboratory, Upton, NY 11973, USA.
Angewandte Chemie (International ed. in English)
|September 13, 2023
概括
研究人员开发了一种基于硫的新型电解质,即2,2,2-三甲基酸 (TFEM),以提高金属电池 (LMB) 的循环稳定性. 这种新的电解质提高了阳极的稳定性,降低了粘度,在苛刻的条件下实现了高性能.
科学领域:
- 材料科学 材料科学 材料科学
- 电化学 电化学 电化学
- 储能 储能 储能 储能 储能 储能
背景情况:
- 金属电池 (LMB) 提供高能量密度,但需要稳定的电解质,用于金属阳极和高压阴极,如LiNix Mny Co1-x-y O2 (NMC).
- 现有的以太电解质是阳极稳定的,但缺乏阴极稳定性,而硫电解质表现出良好的阴极稳定性,但存在高粘度和较差的阳极稳定性.
- 提高NMC兼容电解质中的阳极稳定性比提高以太基系统中的阴极稳定性更少被探索.
研究的目的:
- 为解决硫基电解质的局限性,特别是高粘度和低阳极稳定性,用于实际的金属电池应用.
- 设计和合成一种新的硫衍生物,提高阳极稳定性和电解质湿性质.
- 在具有挑战性的循环条件下,在LMB中证明新电解质的电化学性能.
主要方法:
- 硫化合物的分子修饰使用共振和电子撤回效应来调整属性.
- 引入额外的氧气和化以减少分子粘度和易斯度.
- 使用2,2,2-三甲基酸 (TFEM) 作为单一溶剂的电解质配方.
- 用NMC811阴极和金属阳极在低N/P比率下进行LMB的电化学循环.
主要成果:
- 与传统的硫相比,修改后的硫分子TFEM的粘度显著降低,湿能力提高.
- TFEM表现出增强的阳极稳定性,由于减少了易斯基本性,对Li+的反应性下降.
- 使用TFEM作为单溶剂电解质的LMB在恶劣条件下 (低N/P比率) 在C/3放电速率下160个周期后实现了90%的容量保留.
结论:
- 硫电解质的分子工程可以有效地克服粘度和阳极不稳定性的限制.
- TFEM代表了一个有前途的单溶剂电解质,用于稳定和高性能金属电池.
- 这项工作为为下一代储能系统开发先进的电解质提供了新的战略.
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