Metal-CO₂ Batteries on the Road: CO₂ 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 O₂ atmosphere, while CO₂ and moisture in ambient air can significantly impact the electrochemical performance of metal-O₂ batteries. In the study of CO₂ contamination on metal-O₂ batteries, it has been gradually found that CO₂ can be utilized as the reactant gas alone; namely, metal-CO₂ batteries can work. On the other hand, investigations on CO₂ fixation are in focus due to the potential threat of CO₂ on global climate change, especially for its steadily increasing concentration in the atmosphere. The exploitation of CO₂ in energy storage systems represents an alternative approach towards clean recycling and utilization of CO₂ . Here, the aim is to provide a timely summary of recent achievements in metal-CO₂ 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.