p-d Orbital Hybridization of S-Pt-C Atomic Site Enables Durable Mg-CO₂ Battery.

Abstract

Single-metal-site catalysts integrated within covalent organic framework (COFs) combine maximized atomic utilization with tunable porosity and robust coordination environments, enabling efficient CO₂ diffusion, precise active-site control, and enhanced electron transfer for superior performance in metal-CO₂ batteries. However, their practical application is limited by structural instability owing to the weak coordination effect of metal and π electron under high redox-active operating condition. Herein, a p-d orbital hybridization strategy to strengthen metal-support interaction (MSI) by introducing a sulfur atom with lone-pair electrons is reported, achieving highly durable Mg-CO₂ and photo-assisted Li-O₂ batteries. The p-d orbital hybridization strategy effectively lowers the reaction energy barrier and steers the reaction pathway toward the formation of flower-like discharge products, thereby enhancing both the energy conversion efficiency and reversibility of the battery. The Mg-CO₂ battery with strengthen MSI achieves a high stable operation for over 420 h at an ultralow overpotential of 0.34 V and a high capacity of 50 Ah g^-1, representing the best-reported performance among Mg-CO₂ batteries with single-metal-site catalyst to date. In situ electrochemical spectroscopy and theoretical studies prove that the strong MSI decreases discharge/charge energy barriers and switches the product morphology from dense, compact films to flower-like morphology.