title: Solvation structure around the Li(+) ion in succinonitrile-lithium salt plastic crystalline electrolytes.
abstract: Herein, we discuss the study of solvation dynamics of lithium-succinonitrile (SN) plastic crystalline electrolytes by ultrafast vibrational spectroscopy. The infrared absorption spectra indicated that the CN stretch of the Li(+) bound and unbound succinonitrile molecules in a same solution have distinct vibrational frequencies (2276 cm(-1)vs. 2253 cm(-1)). The frequency difference allowed us to measure the rotation decay times of solvent molecules bound and unbound to Li(+) ion. The Li(+) coordination number of the Li(+)-SN complex was found to be 2 in the plastic crystal phase (22 °C) and 2.5-3 in the liquid phase (80 °C), which is independent of the concentration (from 0.05 mol kg(-1) to 2 mol kg(-1)). The solvation structures along with DFT calculations of the Li(+)-SN complex have been discussed. In addition, the dissociation percentage of lithium salt was also determined. In 0.5 mol kg(-1) LiBF4-SN solutions at 80 °C, 60% ± 10% of the salt dissociates into Li(+), which is bound by 2 or 3 solvent molecules. In the 0.5 mol kg(-1) LiClO4-SN solutions at 80 °C, the salt dissociation ratio can be up to 90% ± 10%.
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China. kjyuan@dicp.ac.cn and University of the Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yuneng
authors.initials: Y
authors.lastname: Shen
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China. kjyuan@dicp.ac.cn.
authors.forename: Gang-Hua
authors.initials: GH
authors.lastname: Deng
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China. kjyuan@dicp.ac.cn.
authors.forename: Chuanqi
authors.initials: C
authors.lastname: Ge
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China. kjyuan@dicp.ac.cn.
authors.forename: Yuhuan
authors.initials: Y
authors.lastname: Tian
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China. kjyuan@dicp.ac.cn.
authors.forename: Guorong
authors.initials: G
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China. kjyuan@dicp.ac.cn.
authors.forename: Xueming
authors.initials: X
authors.lastname: Yang
authors.affiliation: College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China.
authors.forename: Junrong
authors.initials: J
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China. kjyuan@dicp.ac.cn.
authors.forename: Kaijun
authors.initials: K
authors.lastname: Yuan