Initial stages of thermal decomposition of LiPF6-based lithium ion battery electrolytes by detailed Raman and NMR spectroscopy
Journal article, 2013

Independent of the specific electrode chemistry, the state-of-the-art lithium ion battery electrolytes based on LiPF6 in organic solvents have a low thermal abuse tolerance and poor cycle life at elevated temperatures. We present here a detailed investigation of the initial stages of the thermal decomposition of LiPF6 in EC/DMC stored at 85 degrees C using Raman and NMR spectroscopy. During storage (up to 160 h), significant amounts of CO2 are evolved, as detected in the Raman spectra. Time-resolved H-1, P-31, and F-19 NMR spectra show the evolution of POF3, POF(OH)(2), POF2(OCH2CH2)(n)F, and POF2OMe as reactive decomposition products. Our unique F-19 NMR approach, measuring while heating with both high energy and time resolution, allows for a first quantitative analysis of the evolved species and reveals several decomposition reactions during the first 30 min up to 72 h, where the rates of HF and POF2OMe formation are surprisingly linear. EC is found to be much less reactive compared to DMC. All information is used in the formulation of an updated decomposition pathway chart for LiPF6 based electrolytes.

Author

Susanne Wilken

Chalmers, Applied Physics, Condensed Matter Physics

Marcel Treskow

Chalmers, Applied Physics, Condensed Matter Physics

Johan Scheers

Chalmers, Applied Physics, Condensed Matter Physics

Patrik Johansson

Chalmers, Applied Physics, Condensed Matter Physics

Per Jacobsson

Chalmers, Applied Physics, Condensed Matter Physics

RSC Advances

2046-2069 (ISSN)

Vol. 3 37 16359-16364

Areas of Advance

Transport

Energy

Materials Science

Subject Categories

Chemical Sciences

DOI

10.1039/c3ra42611d

More information

Created

10/8/2017