We study the solvation of molecules and ions that are key in the context of Molten Carbonate Electrolyser Cells using first-principles simulations. Focusing on the electroreduction of CO2 to CO in a molten carbonate medium, we investigate the solvation of both the reactant CO2 and the product CO in the eutectic LiKCO3, (containing 62 % Li2CO3, 38 % K2CO3,). CO2 is found to spontaneously react with the carbonate ions to form the transient pyrocarbonate species, C2O52-. To investigate the similar reaction that could occur with CO and CO32- to form an oxalate, we simulated that species and found it to be stable in the melt, supporting this hypothesis. We further present the solvation of O2-, finding that it shows preferential formation of a complex with four lithium cations in a tetrahedral arrangement. Estimates of the diffusion coefficients of these species are then reported, showing that CO has the faster diffusion of all the molecules and ions studied.
Carbon Species Solvated in Molten Carbonate Electrolyser Cell from First-Principles Simulations
14 September 2020, Version 2
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