Mohammadi Mohaddese, Benders Stefan, Jerschow Alexej
Department of Chemistry, New York University, 100 Washington Square East, New York, New York 10003, USA.
J Chem Phys. 2020 Nov 14;153(18):184502. doi: 10.1063/5.0026450.
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 and Li 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 ∼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.
我们使用核磁共振光谱、分子动力学和粘度测量方法研究锂离子的水合溶剂化动力学。研究了几种弛豫机制，以解释自旋晶格弛豫向高浓度强烈增加的现象。使用锂和锂同位素有助于确定四极相互作用对弛豫速率的贡献。特别地，发现在浓度约为10摩尔时，四极相互作用构成了最强的贡献。次强的贡献来自与旋磁比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，实验弛豫速率似乎得到了充分解释。溶剂化动力学的研究，特别是在高浓度下的研究，可能与水性锂离子可充电电池中的电解质动力学相关。
