Enhanced Stability of Coated Carbon Electrode for Li‐O2 Batteries and Its Limitations

Abstract Li‐O2 batteries are promising next‐generation energy storage systems because of their exceptionally high energy density (≈3500 W h kg−1). However, to achieve stable operation, grand challenges remain to be resolved, such as preventing electrolyte decomposition and degradation of carbon, a commonly used air electrode in Li‐O2 batteries. In this work, using in situ differential electrochemical mass spectrometry, it is demonstrated that the application of a ZnO coating on the carbon electrode can effectively suppress side reactions occurring in the Li‐O2 battery. By probing the CO2 evolution during charging of 13C‐labeled air electrodes, the major sources of parasitic reactions are precisely identified, which further reveals that the ZnO coating retards the degradation of both the carbon electrode and electrolyte. The successful suppression of the degradation results in a higher ox…