BaTaLiO: a new highly oxygen deficient perovskite oxide-ion conductor

High oxide-ion and proton conductivity in perovskite oxides has been well documented in the literature. Herein, we report a highly oxygen deficient perovskite oxide BaTa 0.5 Li 0.5 O 2.5 (BTLO) as a new oxide-ion conductor. The material exhibits a simple primitive cubic perovskite structure (S.G.: Pm 3&cmb.macr; m ) with lattice parameter a = 4.1024(1) Å and completely disordered Ta and Li cations on the B-site. The ionic conduction is predominated by oxide-ion over a wide range of oxygen partial pressure and temperature, with an ionic conductivity comparable to the state-of-the-art yttria-stabilized zirconia. Ab initio molecular dynamics (AIMD) simulations reveal that oxide-ion diffusion follows three-dimensional pathways, involving oxygen vacancy hopping along the edges of (Ta/Li)O 4 tetrahedra and (Ta/Li)O 6 octahedra. This work may inspire future work to discover new oxide-ion conductors in similar systems. BaTa 0.5 Li 0.5 O 2.5 : a new highly oxygen deficient perovskite oxide-ion conductor with disordered oxygen vacancies is reported for the first time.