Oxygen-Mediated Isotropic Lithium Diffusion on Electrocatalyst Surface for Efficient Li-CO₂ Batteries.

Abstract

By combining renewable electricity storage with electrochemical CO₂ recycling, Li-CO₂ batteries offer a dual-purpose technology that is critical for carbon neutrality. However, their efficiency is severely limited by the sluggish reaction of insulating discharge products, including Li₂CO₃, which are dominated by Li⁺ diffusion and coupling process. In this study, a new type of oxygen-mediated isotropic lithium diffusion on the electrocatalyst surface is discovered, resulting in a breakthrough in dynamic rates and high-current performance in Li-CO₂ batteries. Using Ru-based electrocatalysts as a proof-of-concept, the oxygen isotropic mediation brings short-range oxygen coordination as Li⁺ jumping channels, and long-range isotropic structures for free Li⁺ diffusion pathways. The electrocatalyst achieved Li⁺ surface diffusion at 5.0 × 10^-11 cm s^-1, a tenfold improvement over rates measured on conventional electrocatalysts, and directly accelerated the Li₂CO₃ nucleation and decomposition. The electrocatalyst-based cells demonstrated the elevated discharge and charge voltage of 2.86 and 3.76 V. This study provides guidelines for electrocatalyst design with ultrafast ion diffusion on the surface and accelerates the adoption of efficient Li-CO₂ batteries.