To explore the potential formation of MgCO3 alongside C and CO2 through CO splitting, our study investigated the Gibbs free energy of CO disproportionation, which was calculated to be 3.46 eV. Notably, the rate-controlling step of the initial splitting reactions ( ) and ( ) exhibited free energy changes of -1.02 eV and 3.46 eV, respectively. In contrast, the second splitting reactions ( ) and ( ) displayed free energy changes of -0.63 eV and 3.06 eV, respectively. While the first splitting reaction, leading to the formation of MgCO3 and CO nucleation from MgC2O4, is thermodynamically favorable, the subsequent CO disproportionation reaction to produce C and CO2 is found to be energetically uphill. This suggests that MgC2O4 can indeed split into MgCO3 and CO, but the subsequent decomposition into C and CO2 is hindered. It is worth noting that the Gibbs free energy calculations for the formation of MgCO3, along with MgO and C through MgCO3 and CO, accompanied by electron transfer, reveal a free energy barrier of 2.30 eV at U = 2.13 V, in contrast to the energetically unfavorable formation of C and CO2. Thus, it can be concluded that while the intermediate MgC2O4 formation is thermodynamically favorable, it will undergo further decomposition and electron transfer reactions to eventually form the final discharge product, MgCO3, along with MgO and C (denoted as (3) in Figure .