Electrical conductivity in Ni-doped nonstoichiometric lithium tantalite was described by a new theoretical approach. From the experience, we have proposed the new vacancy models which are able to describe substitutional mechanism in Ni-doped lithium tantalite. A combinaison of phase transition theory and generalised vacancy models allows us to establish a new expression of electrical conductivity which takes into account the defect structure of Ni-doped lithium tantalate. Calculations of the conductivity in Ni-doped nonstoichiometric lithium tantalate reveal good correspondence with experimental results.Electrical conductivity in Ni-doped nonstoichiometric lithium tantalite was described by a new theoretical approach. From the experience, we have proposed the new vacancy models which are able to describe substitutional mechanism in Ni-doped lithium tantalite. A combinaison of phase transition theory and generalised vacancy models allows us to establish a new expression of electrical conductivity which takes into account the defect structure of Ni-doped lithium tantalate. Calculations of the conductivity in Ni-doped nonstoichiometric lithium tantalate reveal good correspondence with experimental results
