Operando Pulse Electrochemical Mass Spectrometry for Nondestructive and Long-Term Gas Analysis in Practical Lithium-Ion Pouch Batteries

Lithium-ion battery (LIB) technology is important for electric transportation and large-scale energy storage, where a gas-related parasitic reaction is one of the constraints. Consequently, developing a gas analysis method for mechanism analysis and safety warnings is of practical significance but often challenging. Here, an operando pulse electrochemical mass spectrometry (p-EC-MS) technique is reported, featuring a specialized electrochemical cell, a programmed pulse collection system, a carrier gas inlet system, a gas replenishment system, and a quantitative algorithm. As a proof of concept, both model experiment and practical LIB operation are examined, showcasing its capability for nondestructive and long-term gas analysis. Furthermore, secondary parasitic reactions resulting from gas consumption (e.g., gas cross-talk) in LIBs, a phenomenon rarely detected by traditional differential electrochemical mass spectrometry, have been observed. We believe that the p-EC-MS technique can provide fundamental insights into gas behavior and design strategies to enhance the safety and durability of practical LIBs.