Development of a lithium ion cell enabling in situ analyses of the electrolyte using gas chromatographic techniques

Monitoring the electrolyte decomposition in lithium ion battery electrolytes is key to understand their influence on electrochemical cell performance. Gas chromatographic techniques have been reported to provide valuable information benefiting from the separation of the analytes of interest. During this study a new cell design has been developed, which provides the opportunity to carry out in situ analyses. For this purpose, the cell based on the 18650 format was designed to be compatible with gas chromatographic sampling routines e.g. by solid phase microextraction. In this case study we were able to provide information about the consumption of vinylene carbonate over a course of 200 cycles, while retaining a good cycling performance. Additionally, the formation and accumulation of one of the major decomposition products of the electrolyte was monitored. The developed new technique will contribute to gain information about the electrolyte constituents beyond state-of-the-art post mortem techniques.