Achieving ultra-stable Li-CO2 battery via synergistic effect of RuxIr1-xO2 bimetallic oxide catalyst

Abstract

Rechargeable Li-CO₂ batteries have attracted worldwide attention in recent years since it can realize the eco-friendly utilization of greenhouse gas CO₂ and offer high theoretical energy density. However, the current Li-CO₂ battery still has the shortcomings of a high charging platform and poor cycling performance. Herein, the mixed ultrafine Ru/Ir oxide nanoparticles are uniformly loaded on carbon nanotubes (Ru_xIr_1-xO₂/CNTs) as an efficient air cathode for Li-CO₂ battery by a simple one-step hydrothermal method. The Li-CO₂ battery with Ru_xIr_1-xO₂/CNTs cathode performed the discharge specific capacity of 3956.7 mAh g⁻¹, ultralong cycling stability (>6000 h), low charge platform and over-potential (3.85 V/1.22 V). The excellent electrochemical performance is attributed to the synergistic effect of Ru_xIr_1-xO₂ bimetallic oxide, enhancing the cycling stability and affecting the formation/ decomposition mechanism of the discharge product. This work provides an in-depth perspective on the catalyst effect and identifies a feasible way to construct an ultra-stable Li-CO₂ battery.