An important strategy to improve the performance of batteries is to understand gas formation during cell cycling. Gas formation in LIBs and SIBs typically occurs during cell formation (SEI formation) where larger amounts of gases such as CO, CO2 or C2H2 are released . Gas can also be released during cycling of the battery. In this case, gas formation typically indicates undesired side reactions due to e.g. overcharging or overdischarging which can cause decomposition of the electrolyte and/or the electrode materials. Even a very minor gas release can be taken as sign for a continuous cell degradation which limits cycle life. In order to improve battery performance, detecting gases and linking their formation to parameters like the state of charge or temperature is therefore highly desirable . A method that combines electrochemical measurements with gas analysis is differential electrochemical mass spectrometry (DEMS) . The method provides information on the types and amounts of gases that are being released during electrochemical experiments and hence may enable a more knowledge-based improvement in materials development and battery cycling conditions.