Fast ionic conduction in cubic hafnium garnet Li7La3Hf2O12

A new member of the family of garnets with fast lithium ion conduction has been found with the composition Li7La3Hf2O12 The anion arrangement corresponds to the oxygen framework in garnets, e g, in Ca3Fe2Si3O12 Hafnium is coordinated octahedrally while the lanthanum environment can be described as a distorted cube Lithium occupies a large number of positions with tetrahedral, trigonal planar, and metaprismatic coordination Li7La3Hf2O12 shows a lithium bulk ion conductivity of 2 4 x 10(-4) Omega(-1) cm(-1) at room temperature with an activation energy of 0 29 eV