Enhanced Electrochemical Performance of Aprotic Li-CO2 Batteries with a Ruthenium-Complex-Based Mobile Catalyst

Li-CO 2 batteries are regarded as next-generation high-energy-density electrochemical devices, with great importance in the understanding of Li-air batteries and promising potential for application in the aviation industry. However, the greatest challenge arises from the formation of the discharge product, Li 2 CO 3 , which would accumulate and deactivate heterogenous catalysts to cause huge polarization. Herein, Ru(bpy) 3 Cl 2 was employed as a solution-phase catalyst for Li-CO 2 batteries and proved to be the most effective one screened so far. Spectroscopy and electrochemical analyses elucidate that the Ru(II) center could interact with both CO 2 and amorphous Li 2 C 2 O 4 intermediate, thus promoting electroreduction process and delaying carbonate transformation. As a result, the charge potential is reduced to 3.86 V and over 60 discharge/charge cycles are achieved with a fixed capacity of 1000 mAh g -1 at a current density of 300 mA g -1 . Our work provides a new avenue to improve the electrochemical performance of Li-CO 2 batteries with efficient mobile catalysts.