In Situ, Time-Resolved Measurements of Lithium-Ion Battery Gases During Cell Formation Using Mid-IR Laser Absorption Spectroscopy

and CO representing the largest fractions. Trace amounts (100-300 ppm) of carbonyl sulfide (OCS) were also measured. The evolution of gas mole fractions, moles, and their production rates with respect to time and voltage are discussed in the context of production mechanisms and electrochemical events. The presented results demonstrate the ability of LAS to provide quantitative non-extractive and calibration-free speciation measurements with high temporal resolution in Li-ion battery cells.