Rechargeable Al-CO₂ Batteries for Reversible Utilization of CO₂

The excessive emission of CO₂ and the energy crisis are two major issues facing humanity. Thus, the electrochemical reduction of CO₂ and its utilization in metal-CO₂ batteries have attracted wide attention because the batteries can simultaneously accelerate CO₂ fixation/utilization and energy storage/release. Here, rechargeable Al-CO₂ batteries are proposed and realized, which use chemically stable Al as the anode. The batteries display small discharge/charge voltage gaps down to 0.091 V and high energy efficiencies up to 87.7%, indicating an efficient battery performance. Their chemical reaction mechanism to produce the performance is revealed to be 4Al + 9CO₂ ↔ 2Al₂ (CO₃ )₃ + 3C, by which CO₂ is reversibly utilized. These batteries are envisaged to effectively and safely serve as a potential CO₂ fixation/utilization strategy with stable Al.