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.