Electrochemical conversion of CO2 to carbon and oxygen in LiCl-Li2O melts

Carbon dioxide was electrochemically decomposed to carbon and oxygen gas in molten LiCl-5.0 wt.% Li2O molten salts at 903 K using a titanium cathode and inert platinum anode. CO2 chemically dissolves into the LiCl-Li2O melt by reacting with Li2O, changing the electrolyte LiCl-Li2O-CO2 into Li2CO3 and LiCl. Carbonate anions are electrochemically reduced to carbon on the cathode, while oxygen complexes of carbonate anions are oxidized at the anode, generating O2. Electrolysis of the LiCl-5.0 wt.% Li2O molten salt under a CO2 atmosphere at 0.05 A/cm2 yields anodic gas with a CO2/O2 ratio of 0.42. The CO2/O2 ratio increases with increasing current density. The proposed concept may provide oxygen and fuel supplies to future explorers and inhabitants of Mars.