Ionic Diffusion in CO2 Adsorption by Li4SiO4

CO_{2} adsorption by Li_{4}SiO_{4} has garnered significant attention for its potential in effectively capturing CO_{2}. The slow diffusion-controlled reaction within the product layer is a key factor affecting CO_{2} adsorption. However, no research has been conducted to study the diffusion mechanism. Here, ionic diffusion was systematically comprehended through inert-marker experiments and first-principles calculations. An electron probe test clearly captures the movement of inert-marker Pt into the product layer, thus the outward transfer of O^{2-} and Li^{+} ions is proposed to be the dominant diffusion mode. Density functional theory calculations also confirm the diffusion of O^{2-} and Li^{+} with the former being the speed controlling step.