Zhang Han, Lin Yangfan, Wang Jianhui
Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310030, China.
J Phys Chem Lett. 2024 Aug 15;15(32):8378-8386. doi: 10.1021/acs.jpclett.4c01613. Epub 2024 Aug 8.
The physicochemical properties of electrolytes profoundly impact the energy density, rate performance, and manufacturability of rechargeable lithium batteries. Localized high-concentration electrolytes (LHCEs), a novel electrolyte class, have attracted considerable interest, yet the impact of diluents on their physicochemical properties remains unclear, as most reports involve only a few samples. Here we prepared 345 electrolyte samples using 21 diluents and systematically investigated the effect of diluent type and content on the miscibility, density, viscosity, and ion conductivity of LHCEs. We found that the physicochemical properties of LHCEs are mainly affected by the diluents' density and viscosity, regardless of type. Notably, the ionic conductivity exhibits two typical variance trends, "volcano" and "descending," both correlating strongly with diluents' viscosity rather than dielectric constant, a parameter commonly employed in electrolyte design. This anomaly can be explained by the "plum pudding" solvation model, providing essential insights for developing lightweight, highly fluid, and conductive LHCEs.
电解质的物理化学性质对可充电锂电池的能量密度、倍率性能和可制造性有着深远影响。局部高浓度电解质（LHCEs）作为一种新型电解质类别，已引起了广泛关注，但稀释剂对其物理化学性质的影响仍不明确，因为大多数报告仅涉及少数样品。在此，我们使用21种稀释剂制备了345个电解质样品，并系统地研究了稀释剂类型和含量对LHCEs的混溶性、密度、粘度和离子电导率的影响。我们发现，无论类型如何，LHCEs的物理化学性质主要受稀释剂的密度和粘度影响。值得注意的是，离子电导率呈现出两种典型的变化趋势，即“火山型”和“下降型”，这两种趋势均与稀释剂的粘度密切相关，而非与电解质设计中常用的介电常数相关。这种异常现象可以通过“李子布丁”溶剂化模型来解释，这为开发轻质、高流动性和高导电性的LHCEs提供了重要见解。
