在MgV2O4阴极表面上的电解质活性
Heonjae Jeong1,2, Dan-Thien Nguyen1,3, Yingjie Yang1,4
1The Joint Center for Energy Storage Research (JCESR), Argonne National Laboratory, Lemont, Illinois 60439, United States.
ACS applied materials & interfaces
|October 8, 2023
概括
了解电池中的电解质分解是防止表面被动化的关键. 这项研究表明,Mg2+溶解驱动着阴极表面的电解质分解,形成被动化化物.
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
- 计算化学计算化学
背景情况:
- 电极-电解质接口的不稳定性和表面被动化是多价电池的主要挑战.
- 预测电解质组件在电极表面上的分子相互作用和化学反应性对于电池性能至关重要.
研究的目的:
- 为了研究二三甲硫胺 (Mg) 中电解质物种的内在反应性 (Mg) 在瓦纳酸盐 (MgV2O4) 阴极上的diglyme (G2).
- 阐明电解质分解在电极-电解质接口的机制.
主要方法:
- 第一原则计算研究电解质离子和分子在MgV2O4.4上的吸附和反应性.
- 多模式光谱学 (X射线光电,X射线吸收近边缘结构,电子能量损失) 和传输电子显微镜.
- 离子软着陆技术用于创建明确定义的电解质-MgV2O4接口,用于实验分析.
主要成果:
- 非溶解的[Mg(TFSI) ]+在MgV2O4上呈现出最强的吸附性,而部分溶解的[Mg(TFSI):G2]+则是最有反应性的.
- 在TFSI中预测的C-S键裂变和在G2中预测的C-O键裂变作为占主导地位的分解途径,形成像CF3-和CH3+这样的物种.
- 实验结果证实了电解质分解和MgF2和碳酸盐的形成,特别是[Mg(TFSI:G2]+,证实了理论预测.
结论:
- 在MgV2O4表面的Mg2+溶解通过吸附和电荷转移触发电解质分解,导致化物被动化.
- 表面诱导的分解比内在的气相解离更受青.
- 设计阳极稳定的电解质需要系统,以促进离子溶解.
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