Unveiling gas production in rechargeable batteries via in situ differential electrochemical mass spectrometry

Abstract

The operation of rechargeable batteries is always accompanied by the generation and accumulation of gases due to side reactions. Timely detection of gas production is particularly critical for ensuring battery safety and extending operational lifetimes. In this review, an emerging spectrometry technique—in situ differential electrochemical mass spectrometry (DEMS)—for real-time gas detection, aiming to provide a detailed understanding of gas production behavior and underlying mechanisms, was systematically reviewed. The fundamentals of DEMS equipment and its significant development and evolution process in battery gas detection are discussed. By analysing extensive experimental data, the effects of external parameters on gas production in batteries and their quantitative impacts were evaluated. To elucidate the essence of gas generation, the reaction mechanisms are comprehensively analysed and discussed at the molecular scale, utilizing in situ DEMS detection data and complementary characterization methods. Furthermore, effective strategies for suppressing gas production, ranging from laboratory research to industrial applications, are introduced. Finally, promising directions for advancing gas monitoring technologies are identified to inspire the revolutionary design of safer and longer-lasting batteries.