Nuclear magnetic resonance spin-lattice relaxation of lithium ions in aqueous solution by NMR and molecular dynamics
Nuclear magnetic resonance spin-lattice relaxation of lithium ions in aqueous solution by NMR and molecular dynamics
复制标题
水溶液中锂离子的核磁共振自旋晶格弛豫，核磁共振和分子动力学
DOI：
10.1063/5.0026450
复制
发表时间：
2020-11-14
影响因子：
4.4
通讯作者：
Jerschow, Alexej
中科院分区：
文献类型：
--
作者：
Mohammadi, Mohaddese;Benders, Stefan;Jerschow, Alexej
我们利用核磁共振波谱、分子动力学和粘度测量研究锂离子的水溶剂化动力学。研究了几种弛豫机制，以解释自旋晶格弛豫向高浓度的强烈增加。 Li-6 和 Li-7 同位素的使用有助于确定四极对弛豫率的贡献。特别是，发现四极相互作用在浓度高于大约 10 摩尔浓度时构成最强的贡献。第二强的贡献来自于与旋磁比的平方成比例的相互作用（主要是偶极相互作用），并且当这些机制在直至饱和浓度的浓度范围内组合时，实验弛豫率似乎得到了充分的解释。溶剂化动力学的研究，特别是在高浓度下，可能与水系锂离子充电电池中的电解质动力学相关。
We study the aqueous solvation dynamics of lithium ions using nuclear magnetic resonance spectroscopy, molecular dynamics, and viscosity measurements. Several relaxation mechanisms are examined to explain the strong increases of spin-lattice relaxation toward high concentrations. The use of both Li-6 and Li-7 isotopes is helpful to identify the quadrupolar contribution to the relaxation rate. In particular, it is found that the quadrupolar interaction constitutes the strongest contribution above a concentration of similar to 10 molal. The next-strongest contribution arises from interactions that scale with the square of the gyromagnetic ratio (mostly the dipolar interaction), and the experimental relaxation rates appear to be fully accounted for when these mechanisms are combined over the concentration range up to the saturation concentration. The study of solvation dynamics, particularly at high concentrations, could be of relevance for electrolyte dynamics in aqueous Li-ion rechargeable batteries.