A reversible lithium–CO2 battery with Ru nanoparticles as a cathode catalyst

Abstract

Li–CO₂ batteries have attracted wide attention owing to their high energy density and ability to utilize carbon dioxide. However, current Li–CO₂ batteries still suffer from several unresolved problems such as low coulombic efficiency and high charge potential, and hence much work is still required to optimize the electrochemical performance of Li–CO₂ batteries. In this work, Ru nanoparticles have been deposited on Super P carbon using a solvothermal method and the resulting material (Ru@Super P) has been employed as a cathode in Li–CO₂ batteries. The Li–CO₂ battery with Ru@Super P as the cathode exhibits significantly reduced charge potential and can be operated for 80 cycles with a fixed capacity of 1000 mA h g⁻¹ at 100 mA g⁻¹, which is by far the best cycling stability among the reported Li–CO₂ batteries. We found that Ru possesses a selective catalytic activity in promoting the reaction between Li₂CO₃ and carbon during charge. This characteristic of Ru helps to avoid electrolyte decomposition and improve the electrochemical performance of Li–CO₂ batteries.