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Updated: Jul 28, 2025

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在电池电解质溶液中量化溶解过渡金属,用NMR偏磁放松增强对电池进行量化

Jennifer P Allen^1,2, Christopher A O'Keefe^1,2, Clare P Grey^1,2

¹Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.

The journal of physical chemistry. C, Nanomaterials and interfaces

|May 31, 2023

概括

核磁共振 (NMR) 放松计可以量化离子电池电解质中的溶解过渡金属,有助于理解容量衰减. 然而,电解质降解使准确的测量变得复杂,特别是在高温下.

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
分析化学分析化学

背景情况:

过渡金属溶解是离子电池容量衰减的一个关键因素.
核磁共振 (NMR) 放松率与磁性物种度相关,为量化溶解金属提供了一种潜在的方法.

研究的目的:

调查NMR放松计对六酸 (LiPF6) 电池电解质中溶解过渡金属 (Ni²⁺,Mn²⁺,Co²⁺,Cu²⁺) 的量化疗效.
为了确定不同核素 (Li,P,F,H) 的灵敏度和精度,用于金属检测.
评估电解质降解对NMR放松计量量化的影响.

主要方法:

测量了 Li, 31P, 19F 和 1H 的纵向和横向放松率,在含有各种过渡金属盐的 LiPF6 电解质溶液中.
研究了在不同温度 (∼20°C和60°C) 储存的电解质样本中从LiMn₂O₄中溶解Mn.
分析了金属溶解对放松增强和检测极限的影响.

主要成果:

核磁共振放松计表明对溶解过渡金属的敏感性,F和H测量显示出比Li和P.31更高的敏感性.
(Mn2+) 显示出最大的放松增强,达到大约0.005mM的检测极限,用于F和H.
在≤20°C溶解的Mn得到了准确的量化,但由于金属溶解的改变,热降解电解质 (储存在60°C) 的准确性下降.

结论:

在离子电池电解质中的过渡金属的现场,非破坏性量化使用NMR放松计是可行的.
该方法对金属溶解的敏感性表明,评估溶解的金属协调球的可能性很大.
电解质降解显著影响NMR放松计量量的准确性,这对基于LiPF的电池的操作研究构成了挑战.

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