Physical and Chemical Properties of Silicone Electrolyte Materials Evaluated by Nuclear Magnetic Resonance Technology

Abstract

Organosilicon compounds are one of the hot topics in research on electrolyte materials, with their physical and chemical properties standing as important parameters for measuring battery performance. In this paper, the structure of CN(CH2)2SiCH3(OCH2CH2OCH3)2(BNS), solvation effect, diffusion coefficient and thermal stability of LiPF6/BNS were analyzed and evaluated by various nuclear magnetic resonance (NMR) methods (i.e., 1H NMR, 13C NMR, DOSY, 7Li NMR and 19F NMR). It was observed that there was a solvation effect between BNS and LiPF6. Cyano (CN) and ether bond (-O-) groups in BNS may help to form complexes with Li+, and the coordination ability of CN is better than that of -O-. The formation of complex bond accelerated dissociation and diffusion of LiPF6, and also improved the thermal stability of electrolyte (LiPF6/BNS). It was proved that decomposition of LiPF6 at high temperature was the main cause of electrolyte failure. The results of this study provided a theoretical basis for the development of new electrolyte compounds and improvement of their performance.

Keywords

• silicone
• electrolyte materials
• 1h nmr
• 13c nmr
• dosy