Emilsson Samuel, Albuquerque Marcelo, Öberg Pernilla, Brandell Daniel, Johansson Mats
Department of Fibre and Polymer Technology, Division of Coating Technology, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
Institute of Physics, Universidade Federal Fluminense (UFF), Praia Vermelha Campus, Boa Viagem, 24210-346 Niterói, Rio de Janeiro, Brazil.
ACS Phys Chem Au. 2024 Nov 10;5(1):80-91. doi: 10.1021/acsphyschemau.4c00078. eCollection 2025 Jan 22.
In an effort to improve safety and cycling stability of liquid electrolytes, the use of dicarbonates has been explored. In this study, four dicarbonate structures with varying end groups and spacers are investigated. The effect of these structural differences on the physical and ion transport properties is elucidated, showing that the end group has a significant influence on ion transport. The solvation structure and ion transport in the dicarbonates are compared to those of the linear carbonates dimethyl carbonate (DMC) and diethyl carbonate (DEC). Although the carbonate coordination numbers (CN) are similar in the different systems, the CN from the anion is higher in dicarbonate electrolytes. At low salt concentrations, rapid solvent exchange is observed in the DMC- and DEC-containing systems, transitioning to a more correlated ion transport at high salt concentration. In contrast, the exchange of solvents around lithium ions (Li) is limited in the dicarbonate systems regardless of the salt concentration, with only one carbonate group from each molecule participating in the coordination. In addition, according to the molecular dynamics simulations, Li mainly moves together with coordinating dicarbonate molecules and anion(s).
为了提高液体电解质的安全性和循环稳定性，人们对二碳酸酯的使用进行了探索。在本研究中，研究了四种具有不同端基和间隔基的二碳酸酯结构。阐明了这些结构差异对物理和离子传输性质的影响，表明端基对离子传输有显著影响。将二碳酸酯中的溶剂化结构和离子传输与线性碳酸酯碳酸二甲酯（DMC）和碳酸二乙酯（DEC）的进行了比较。尽管不同体系中的碳酸酯配位数（CN）相似，但二碳酸酯电解质中来自阴离子的CN更高。在低盐浓度下，在含DMC和DEC的体系中观察到快速的溶剂交换，在高盐浓度下转变为更相关的离子传输。相比之下，无论盐浓度如何，二碳酸酯体系中锂离子（Li）周围的溶剂交换都受到限制，每个分子只有一个碳酸酯基团参与配位。此外，根据分子动力学模拟，Li主要与配位的二碳酸酯分子和阴离子一起移动。
