AVS 64th International Symposium & Exhibition
    Applied Surface Science Division Friday Sessions
       Session AS+MS-FrM

Paper AS+MS-FrM4
In situ Liquid SIMS Investigation of Ion Solvation in Electrolytes for Lithium Ion Batteries

Friday, November 3, 2017, 9:20 am, Room 13

Session: Unlocking the Sample History: Forensics and Failure Analysis
Presenter: Zihua Zhu, Pacific Northwest National Laboratory
Authors: Z.H. Zhu, Pacific Northwest National Laboratory
Y. Zhang, Pacific Northwest National Laboratory
Z. Xu, Pacific Northwest National Laboratory
M. Su, Pacific Northwest National Laboratory
C. Wang, Pacific Northwest National Laboratory
X.F. Yu, Pacific Northwest National Laboratory
J.G. Wang, Pacific Northwest National Laboratory
Correspondent: Click to Email
Ion-solvent interactions are of great fundamental and practical importance. However, many mysteries have long been existing in this field. For example, for the electrolytes used for Li ion batteries, preferential solvation and coordination number of a Li+ ion are two interesting questions in hot debates so far. A major reason for above situation is lacking of reliable analysis techniques that can provide direct molecular information to elucidate ion-solvent interactions. In this work, in situ liquid SIMS was used to examine salt ion-solvent molecule interactions in several representative electrolytes used for Li ion batteries. Our data of the LiPF6 in EC: DMC electrolyte show very strong molecular evidence that EC is preferentially solvated with Li+, supporting previous ESI-MS and NMR results, but against recent Raman results. In addition, our data suggest that although the coordination number of a Li+ ion can be as high as six in bulk electrolytes, three of them may be more stable than the remaining ones. In addition, it was observed that Li+ and FSI- ions tend to well-separated in 1.0 M LiFSI in DME electrolyte, consistent with our MD simulation results. As a comparison, many ion clusters were observed in the same concentration of LiPF6 in EC: DMC electrolyte. The above findings suggest that in situ liquid SIMS can provide key evidence for better understanding of the ion-solvent interactions in the electrolytes for Li ion batteries.