MOF Nanosheet Enable Accelerated Redox Kinetics and Ultralow Overpotential for Light-Assisted Li-CO2 Battery.

Lithium-carbon dioxide (Li-CO₂) batteries have attracted much attention due to their high energy density, low cost, and carbon sequestration. However, the sluggish conversion kinetics between CO₂ and the discharge product lithium carbonate (Li₂CO₃) have hindered their practical applications. Herein, a flower-like photosensitive metal-organic framework (FJU-115-NS) has been employed as a cathodic electrocatalyst for Li-CO₂ batteries. The FJU-115-NS with well-ordered micropores and abundant exposed catalytic sites can effectively facilitate lithium ion transport and catalyze the Li₂CO₃ formation/decomposition, leading to improved battery performance. At a current density of 200 mA g⁻¹, the FJU-115-NS battery exhibits a substantial discharge capacity of 31579.34 mA h g⁻¹, a low overpotential of 1.31 V, and stable operation over 3200 h. Importantly, under light irradiation, the charging voltage significantly dropped from 4.45 V (without light) to 3.43 V at a high current density of 2 A g⁻¹. Additionally, the cell demonstrated an exceptionally low overpotential of just 0.45 V at a current density of 200 mA g⁻¹, highlighting its enhanced efficiency under light-assisted conditions. This work provides valuable guidance for developing light-assisted MOF catalysts to upgrade the longevity and energy efficiency of Li-CO₂ batteries.