A new non-aqueous Li-CO/CO2 battery with the main discharge products being Li2CO3 and carbon is introduced for the first time. Our findings demonstrate that with the addition of CO, the components and morphology of the discharge products are skillfully tailored, becoming more uniform, with poorer crystallinity and better conductivity. Thanks to these features, the utilization of a cathode in the Li-CO/CO2 battery system is increased and the discharge products are more easily decomposed. These positive effects caused by CO endow the Li-CO/CO2 battery with enhanced electrochemical performances.