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