Platinum Coated Capillary Enhanced Gas Raman Spectroscopy: Analyzing the Multi-Gas Release From Lithium-Ion Batteries After Formation

Understanding the intricate and interconnected mechanisms of gas generation in lithium-ion batteries (LIBs) necessitates real-time multicomponent gas measurements. This study introduces a device based on platinum-coated capillary (PCC) enhanced Raman spectroscopy to simultaneously detect various gases released from lithium-ion pouch cells, facilitating analysis of battery operating conditions. Utilizing a PCC as a hollow-core optical waveguide enhances the collection efficiency of Raman signals from gases within the capillary while ensuring rapid gas filling due to its compact size, enabling real-time multicomponent gas detection. The system’s dedicated gas chamber and capillary have a total internal volume of 6 mL, achieving a response time of 3 s at a gas flow rate of 1000 standard cubic centimeters per minute (sccm). With an excitation light power of 5 W, the limits of detection (LOD) for various gases are within 100 ppm at 60 s. The gases produced after the battery formation process are detected. Analysis of the gas species and concentrations generated inside the battery reveals the release of C2H4, CH4, H2, and CO. Finally, the total volume of gases emitted by the battery after solid-electrolyte interphase (SEI) formation is calculated to be 7.29 mL, with C2H4 being the dominant component. This system offers advantages such as miniaturization and the potential for real-time measurement of gas generation in batteries.