When the Li + ion occupied the 8MR being crossed, slightly off center of the elliptical window (Li2 site; 1Si-1Li-8MR model, fig. ), the diffusion of both C2H4 and C2H6 was partially obstructed. For diffusion to occur, the Li + ion had to be displaced from its original position, moving away from the negatively charged O atoms bonded to Si. This displacement incurred an energy penalty, creating a "trapdoor" effect (Fig. and). This effect is illustrated by intermediates structures (ⅲ) and (ⅳ) in Fig. (bottom) and in figs. S49b and S50c. The π interaction between C2H4 and the Li + ion within the 8MR stabilizes the system, resulting in a higher activation barrier for C2H6 (153 kJ/mol) compared to C2H4 (114 kJ/mol) (Table ). These findings highlight the nuanced effects of protons and Li⁺ ions on diffusion, with Brønsted acid sites promoting C₂H₄ transport and Li⁺ ions introducing diffusion barriers that vary based on their position within the framework.