Li 3 N has a layered structure, with alternating layers of Li 2 N layers and pure Li, as illustrated in Figure . We refer to the Li sites within the pure Li layers as Li and those within the Li 2 N layers as Li . At 300 K, Li + ions in Li 3 N undergo three-dimensional diffusion, with a rate of 1.2 × 10 -3 S cm -1 in the ab-plane and 1 × 10 -5 S cm -1 along the c-axis . Notable, the rate of 1.2×10 -3 S cm -1 stood as the highest recorded roomtemperature Li + ion conductivity for a crystalline phase for many years. Commercial applications of Li 3 N, however, have been hindered by a low decomposition potential of 0.45 V versus Li + /Li .