The Effect of Concentration of Lithium Salt on the Structural and Transport Properties of Ionic Liquid-Based Electrolytes

Frontiers in Chemistry

Shengli Wu¹  Qing Zhou¹  Feng Huo¹  Nicolas von Solms²  Hongyan He²  Suojiang Zhang³  Xiaodong Liang⁴  Jiahuan Tong⁴ 

[1] Biochemical Engineering, Technical University of Denmark, Lyngby, Denmark;Beijing Key Laboratory of Ionic Liquids Clean Process, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China;College of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing, China;;Department of Chemical &

关键词: ionic liquids;    electrolytes;    battery;    structure and property;    MD simulations;   

DOI  :  10.3389/fchem.2019.00945

来源: DOAJ

【 摘 要 】

Ionic liquids (ILs) are used as electrolytes in high-performance lithium-ion batteries, which can effectively improve battery safety and energy storage capacity. All atom molecular dynamics simulation and experiment were combined to investigate the effect of the concentration of lithium salt on the performance of electrolytes of four IL solvents ([Cnmim][TFSI] and [Cnmim][FSI], n = 2, 4). The IL electrolytes exhibit higher density and viscosity; meanwhile, larger lithium ion transfer numbers as the concentration of LiTFSI increases. Furthermore, in order to explore the effect of the concentration of lithium salt on the ionic associations of Li+ and anion of IL, the microstructures of the lithium salt in various IL electrolytes at different concentrations were investigated. The structural analysis indicated that strong bidentate and monodentate coordination was found between Li+ and anion of all IL electrolytes. Both cis and trans isomerism of [FSI]− were observed in [FSI]−-type IL electrolyte systems. Furthermore, the existence of the ion cluster [Li[anion]x](x−1)− in IL electrolytes and the cluster became more closed and compact as the concentration of LiTFSI increases.

【 授权许可】

Unknown