Understanding how nanoscale structure governs interfacial reactivity remains a central challenge in alkali‐metal batteries. Accurate attribution of gas evolution processes is particularly difficult in conventional online electrochemical mass spectrometry (OEMS), where electrolyte decomposition and ionization‐induced fragmentation often obscure structure‐dependent contributions from electrode materials and typically necessitate isotopically labeled electrolytes. Here, we introduce a strategy for nongassing OEMS setup that enables structure‐resolved analysis of electrode‐derived gas evolution at electrode–electrolyte interfaces, allowing unambiguous isolation of gas formation, originating from the working electrode without isotopic labeling. The capability of this platform is demonstrated using commercially relevant conductive carbons as model nanostructured interfaces. Under anodic polarization, CO 2 is identified as the dominant gaseous decomposition product for all investigated carbons. The total amount of evolved CO 2 exhibits a clear qualitative correlation with the specific surface area. Beyond that, systematic trends in CO 2 evolution depend on disorder degree of carbon. These results reveal that both nanoscale surface architecture and local bonding jointly influence the oxidative stability of carbon interfaces in alkali‐metal battery environments. Overall, this work establishes a robust and broadly applicable nongassing OEMS platform for structure‐resolved investigation of interfacial gas evolution and highlights the nonnegligible role of carbon additives to the total gas evolution.
Gatti et al. (Wed,) studied this question.