Metal-CO Batteries on the Road: CO from Contamination Gas to Energy Source.

Rechargeable nonaqueous metal-air batteries attract much attention for their high theoretical energy density, especially in the last decade. However, most reported metal-air batteries are actually operated in a pure O atmosphere, while CO and moisture in ambient air can significantly impact the electrochemical performance of metal-O batteries. In the study of CO contamination on metal-O batteries, it has been gradually found that CO can be utilized as the reactant gas alone; namely, metal-CO batteries can work. On the other hand, investigations on CO fixation are in focus due to the potential threat of CO on global climate change, especially for its steadily increasing concentration in the atmosphere. The exploitation of CO in energy storage systems represents an alternative approach towards clean recycling and utilization of CO . Here, the aim is to provide a timely summary of recent achievements in metal-CO batteries, and inspire new ideas for new energy storage systems. Moreover, critical issues associated with reaction mechanisms and potential directions for future studies are discussed.