Lithium conducting garnets, Li 3 Ln 3 Te 2 O 12 (Ln = Y, Pr, Nd, Sm-Lu), typically contain 5-7 formula units where lithium ions occupy at tetrahedral and octahedral sites, as depicted in Fig. . Since the original work by Murugan et al. , it has attracted numerous experimental and theoretical studies. It is observed that at low lithium content, Li 3 Ln 3 Te 2 O 12 , where Li + ions are tetrahedrally coordinated, does not show significant ionic conductivity (σ ≈ 10 -5 S cm -1 in Fig. )) . However, higher ionic conductivity has been achieved for Li-rich, "stuffed garnets," such as Li 5 La 3 M 2 O 12 (M = Nb, Ta, and Sb), Li 6 ALa 2 M 2 O 12 (A = Mg, Ca, Sr, and Ba; M = Nb and Ta), and Li 7 La 3 M 2 O 12 (M = Zr and Sn) where Li ions occupy the tetrahedral as well as octahedral interstitial sites partially, increasing migrational entropy, ∆S m (eq. 8). Generally, the conductivity value increases with higher Li content. The conductivity is enhanced by 9 orders of magnitude from Li 3 Ln 3 Te 2 O 12 to Li 7 La 3 M 2 O 12 due to significant Li + occupancy switches from tetrahedral to octahedral sites .