High-Efficiency Rechargeable Fe-CO₂ Battery: A Route for Effective CO₂ Conversion and Energy Storage

Because of their high theoretical energy density, metal-CO₂ batteries based on Li, Na, or K have attracted increasing attention recently for meeting the growing demands of CO₂ recycling and conversion into electrical energy. However, the scarcity of active anode material resources, high cost, as well as safety concerns of Li, Na, and K create obstacles for practical applications. Herein, we demonstrate for the first time a high-efficiency (η = 77.2%) rechargeable Fe-CO₂ battery that is composed of iron (Fe) anode and MoS₂-catalysts deposited carbon cathode. MoS₂ catalysts are crucial to the successful acceleration of reaction kinetics of Fe during charge and discharge with a minimum overpotential of the cell. The Fe-CO₂ cell has a higher initial specific capacity of 12,500 mA h g^-1 with an average discharge potential of 0.65 V and operates reversibly with a lower overpotential than that of Li-CO₂ batteries with a cutoff capacity of 500 mA h g^-1. Our Fe-CO₂ battery can effectively convert CO₂ greenhouse gas into electrical energy by consuming 1 ton of CO₂ with usage of 1.23 tons of iron.