Unveiling 4d (Ru)-5d (Pt) Charge Compensation for Li-Oxygen/Air Batteries With Ultralow Overpotentials

Lithium-oxygen batteries hold great promise for next-generation energy storage systems due to their ultrahigh theoretical energy density. However, their development is hindered by high charging overpotentials and poor cycle stability. Herein, we propose a strategy of electronic structure regulation to design a Ru-modified Pt/C catalyst to address the key challenge of tuning the charge overpotential. Electron delocalization occurs from Ru to Pt in RuPt because of the electronegativity difference between Ru and Pt. The calculation results show that the 4d(Ru)-5d(Pt) orbital coupling regulates the d-band distribution of Pt sites in RuPt, including the moderate downshift of d-band center systematically across the Pt's five d-suborbitals and the broadening of d-band above the Fermi energy level. It weakens the adsorption strength towards oxygen-containing species and smooths the energy barriers of stepwise reactions during OER. Experimental results demonstrate that the Ru-Pt/C catalyst significantly reduces the overpotential by ∼1 V compared to Pt/C. Meanwhile, the Li-air battery also presents a low overpotential of 0.75 V after 100 cycles. This work advances the fundamental understanding of d-band regulation via engineering electronic structure in oxygen electrocatalysis and provides a practical pathway to mitigate overpotential-related challenges in high-energy-density metal-air batteries.