Highly dispersed Bi clusters for efficient rechargeable Zn-CO2 batteries

Zn-CO2 batteries hold great promise for carbon-neutral and electricity generation simultaneously, whereas the main obstacle is the development of electrocatalysts with high activity and durability towards CO2 reduction reaction (CRR). Herein, we design atomically dispersed Bi clusters supported on hollow carbon spheres (BiC/ HCS) for effectively reducing CO2 to formate, which shows the highest faradaic efficiency of 97 & PLUSMN; 2% at -0.6 V vs RHE, being comparable to the previously best reported values of Bi-based materials. Experimental and theoretical analyses reveal that the atomic-level Bi-x clusters not only enable high CO2 adsorption but also stabilize the key *HCOO intermediate with a low free energy barrier. Further, an assembled rechargeable Zn-CO2 battery with BiC/HCS as the cathode achieves a peak power density of 7.2 & PLUSMN; 0.5 mW cm(-2) as well as an impressive rechargeability of 200 cycles. This work provides a promising alternative for CO2 utilization and energy storage by Zn-CO2 batteries. Graphical Abstract Bi clusters anchored on hollow carbon spheres have developed as an excellent cathode for Zn-CO2 battery. The catalyst presents a maximal formate faradaic efficiency of 97 & PLUSMN; 2% at -0.6 V vs RHE as well as good durability. The assembled Zn-CO2 battery achieves a peak power density of 7.2 & PLUSMN; 0.5 mW cm(-2) and energy efficiency of 68.9% (@ 3 mA cm(-2)), and a more than 200 cycle rechargeability.