Operando Intermittent Extraction Gas Chromatography‐Mass Spectrometry Technology for Gaseous Products Analysis of Li‐Ion Pouch Cell

Abstract As for the monitoring of gaseous products in Li‐ion batteries, typical differential/on‐line electrochemical mass spectrometry (DEMS/OEMS) characterizations are constrained by inherent limitations, e.g., interference/incompatibility against practical electrochemical long‐term cycling and distortion of product recognition. More critically, DEMS/OEMS exhibits restricted gas monitoring capability, especially as it is inadequate for high specific energy battery systems with increasingly complex side‐reactions and gaseous products evolution. To address these limitations, an operando intermittent extraction gas chromatography‐mass spectrometry (OIE‐GC‐MS) system is developed for a practical pouch‐type cell, equipped with a featured intermittent extraction mode and parallel mass spectrometry (MS) and gas chromatography‐mass spectrometry (GC‐MS). This approach enables full‐dimensional gas evolution monitoring under realistic long‐term cycling conditions across a varying temperature field. Notably, the GC‐MS characterization resolves gaseous products through chromatographic separation, thereby elucidating obscured reaction mechanisms, especially complicated crosstalk/consumption reactions during long‐term cycling. The OIE‐GC‐MS system presents the capability for high‐throughput characterization, achieving an enhancement in product analysis efficiency. The system provides significant insights into the complex reactions leading to battery degradation, establishing a protocol for gas analysis of practical energy storage devices.