Statistical Analysis of Solid Electrolyte Interface Formation: Correlation of Gas Composition, Electrochemical Data and Performance

The SEI is a crucial yet little understood component of lithium-ion batteries. The specific formation processes creating the SEI are still a matter of current research. In our paper, we analyse the electrochemical processes by incremental capacity analysis (ICA) and correlate these results with the evolved gas species and subsequent performance of the cells. 101 cells in total divided in three groups with different electrolytes performed a formation cycle. Afterwards gas-samples of half of the cells were extracted for analysis. We found a good correlation between variations of gas composition and noticeable ICA-data. Furthermore we explore correlations between formation and initial cell performance after a total of 10 cycles. Our results open new possibilities for a better understanding of formation processes.