Even when performing similar simulations with the N 2 initially placed 1.5 Å above the slab, well within the bond-length of Li-N in lithium nitride (1.9 Å), spontaneous dissociation still was not observed in the system. In this case however, the N 2 was found to adsorb in all sites, whether on the surface or at the hollow site. These results imply that despite the high reactivity of lithium, there remains a barrier to N 2 dissociation when considering only lithium and N 2 , in agreement with a previous work. Developing a thermodynamic understanding of N 2 adsorption on lithium, we calculate the enthalpies of adsorption on each of the surface facets using Eq. 6. This provides insight into the strength of the lithium-N 2 bonding without any external influences, with a more negative value indicating increased strength. Comparing the most negative adsorption energies of each considered surface facet (Fig. ), we observe that the N 2 -lithium adsorption is strongest on the 100 facet. Because lithium's role in electrochemical ammonia synthesis is presumed to primarily be a N 2 bond breaker, we focus the rest of our analysis on this facet.