Sodium ionic conduction in complex hydrides with [BH4]- and [NH2]- anions

We report the experimental results of structural and sodium ionic conductive properties of the Na(BH4)-Na(NH2)-NaI system. Na(BH4)(0.5)(NH2)(0.5) with [BH4](-) and [NH2](-) complex anions formed by combining Na(BH4) and Na(NH2) complex hydrides shows the most superior sodium ionic conductivity of 2 x 10(-6) S/cm at 300K because of the specific antiperovskite-type structure with vacancies in the Na+ site Furthermore, Na(BH4)(0.5)(NH2)(0.5) shows a high electrochemical stability of at least 6 V (vs Na+/Na). The result suggests that Na(BH4)(0.5)(NH2)(0.5) could be a potential candidate for solid electrolyte. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4716021]