Efficient CO₂ utilization and sustainable energy conversion via Zn–CO₂ batteries using gaseous CO₂

Rechargeable aqueous Zn–CO₂ battery is a promising technology that combines energy storage and CO₂ utilization to meet the needs of sustainable and eco–friendly energy. However, the practical application of this technology is hindered by factors such as the low current density, low Faradaic efficiency of value–added products, high overpotential, and limited cycles. Cathode catalysts, which are crucial components, significantly influence the performance of the system. There have been several updated publications on cathode materials for aqueous Zn–CO₂ batteries, but there are few reports of high–performance Zn–CO₂ batteries. Herein, a new system for achieving high performance by injecting gas–phase CO₂ was reported. Unlike conventional Zn–CO₂ batteries, the problem of low CO₂ solubility was overcome by injecting gaseous CO₂. The designed Zn–gaseous CO₂ battery, powered by Ag or Au catalysts, achieved that Faradaic efficiencies of CO were 92.72 % and 89.56 % at 4 mA/cm², respectively. The maximum power density of 5.52 mW/cm² and 7.89 mW/cm² for Ag and Au catalysts, respectively, were obtained, which were much larger than the power density of conventional aqueous Zn–CO₂ batteries. In addition, using X–ray diffraction, ex–situ monitoring of the reaction characterizations on Ag and Au cathodes was carried out and the durability of 600 min was achieved, when using Au cathode. These results offer a practical way to design a Zn–CO₂ battery for high-performance energy storage and CO₂ utilization.