Analysis of acidic organo(fluoro)phosphates as decomposition product of lithium ion battery electrolytes via derivatization gas chromatography-mass spectrometry

Abstract

Nowadays, lithium ion batteries (LIBs) are the preferred energy supply for consumer electronics and electric vehicles. But, intrinsic reactions in the LIB system lead to a reduced battery life and impaired safety properties. Organo(fluoro)phosphates (O(F)Ps) as decomposition product of the conducting salt and the organic carbonate solvent molecules of the LIB electrolyte are of high interest due to structural similarities to chemical warfare agents and therefore a supposedly high toxicity. The reaction cascade shows a large variety of O(F)Ps including a wide spread of polarity. In this study, an approach for the investigation of acidic O(F)Ps with gas chromatography-mass spectrometry after derivatization is conducted. Analysis of a model substance, spike experiments in the electrolyte matrix and investigation of thermally treated electrolyte were performed. As a result, derivatization could be achieved in less than three minutes and screening could successfully be shown without impairing the originality of the sample (matrix). This derivatization approach shows the possibility of analysis for both acidic and non-acidic O(F)Ps using only one method.

Keywords: Acidic; Derivatization; GC–MS; Lithium ion battery electrolytes; Non-acidic; Organo(fluoro)phosphates.