Solid–Liquid Interfacial Properties Related to Ionic Conductivity of Mixtures of Metal Oxide Particles and Lithium Bis(fluorosulfonyl)amide-Sulfone Electrolytes (Supporting Information)

We evaluated and compared the physical properties of electrolyte solutions consisting of lithium bis(fluorosulfonyl)amide and sulfone solvents (molar ratio = 1 : 3) and their mixtures containing aluminum oxide (α-Al2O3) or lithium lanthanum zirconate (LLZ) particles of various particle sizes. Sulfolane (SL), 3-methylsulfolane, and ethyl isopropyl sulfone were evaluated as sulfone solvents for the electrolyte solutions. The phase-change heat, phase-change temperature, and spin–spin relaxation time in nuclear magnetic resonance (NMR) measurements decrease in a mixture of SL electrolyte with a metal oxide, with an apparent average liquid thickness in the order of nm resulting from the SL electrolyte solution. This indicates a decrease in molecular mobility around the particle surface. For the α-Al2O3 system, no substantial changes are observed in the activation energy of ionic conductivity, self-diffusion coefficient of Li+ (determined via pulsed-field gradient NMR), or relative cross-peak intensities of Li+ and 1H of SL in the two-dimensional NMR of the mixture. Therefore, despite its low molecular mobility, the SL electrolyte solution at the solid–liquid interface is considered to exhibit an ionic conductivity mechanism similar to that of the bulk electrolyte. It was suggested that LLZ system has a different ionic conduction mechanism than α-Al2O3 system.

本研究评估并对比了由锂双氟磺酰亚胺和磺酰溶剂（摩尔比1：3）组成的电解质溶液及其含有不同粒径的氧化铝（α-Al2O3）或锂镧锆酸锂（LLZ）粒子混合物的物理性质。将磺烷（SL）、3-甲基磺烷和乙基异丙基磺酰作为电解质溶液的磺酰溶剂进行评估。在核磁共振（NMR）测量中，SL电解质与金属氧化物混合物的相变热、相变温度以及自旋-自旋弛豫时间均呈现降低趋势，由此产生的SL电解质溶液的明显平均液膜厚度约为纳米级别，这表明粒子表面附近的分子流动性降低。对于α-Al2O3系统，未观察到离子电导活化能、Li+自扩散系数（通过脉冲场梯度NMR测定）或混合物中SL的Li+和1H二维NMR相对峰强发生显著变化。因此，尽管其分子流动性较低，但SL电解质溶液在固-液界面被认为展现出与体相电解质相似的离子电导机制。有研究表明，LLZ系统与α-Al2O3系统的离子传导机制存在差异。