For Li-CO2 batteries, experimental studies have confirmed that Li2C2O4 is observed as the final discharge product when Mo2C/CNTs and Ru(bpy)3Cl2 are used as cathode catalysts. However, in the case of Au catalysts used as the cathode in Li-CO2 batteries, in situ Raman characterization has detected oxalate species (C2O4 2-) during the initial discharge processes. Nonetheless, the oxalate peaks are quickly replaced by growing signals of carbonate and carbon during subsequent reductions. The only reported work on non-aqueous Mg-CO2 battery claims that the discharge process on Mo2C-CNT cathodes initiates the formation of MgC2O4, which is later followed by the production of insulating MgCO3, MgO, and C at the final stage of discharge. Hence, to understand the final discharge products in non-aqueous Mg-CO2 batteries using RuO2 (211) cathode catalyst, we investigated MgC2O4 splitting reactions employing two disproportionation reactions (denoted as (1) and (2) in Figure ).