Novel solid electrolytes based on borohydrides and higher boranes

This thesis focuses on the preparation and characterization of several new compounds based on borohydrides [BH4]- and closo-boranes [B12H12]2- with the aim of developing new materials for ambient temperature solid electrolytes. The underlying complexity and flexibility of the boron-hydrogen complex anions endows them as promising building blocks for design of superionic conductors. The dynamic reorientation of the anions can facilitate high cationic conductivity with low activation energy. The compounds were prepared mainly via solid state synthesis (mechanochemistry and annealing). X-ray powder diffraction was employed to solve and refine crystal structures, supported by thermal analysis, spectroscopic and computational methods. Impedance spectroscopy was done to establish correlations between ionic conductivity and crystal chemistry. Studies of voids and channels as possible conduction paths were done by using Voronoi-Dirichlet Polyhedra (VDP) method