Consideration of CO₂ absorption mechanism of lithium-metal oxides by calculating electrostatic potentials

Abstract

Li₄SiO₄ is one of the candidate materials for solid CO₂ absorbent. We calculated the electrostatic potentials for respective Li sites in Li₄SiO₄ and compared them to the reactivity of the Li ions to CO₂. The calculated potentials are distributed from -11.6 eV to -17.3 eV. If we choose -13.5 eV as a border line between the shallower and deeper potentials, the number of Li ions over the line and under the line was found to be 26:30 (roughly 1:1). This result seemed to explain the fact that only two Li ions in chemical formula of Li₄SiO₄ can react with CO₂.