Abstract
This article presents the results of a study into the structure, dielectric and conductive properties of Na3Fe2(PO4)3 and Na3FeTi(PO4)3 , obtained by the melt synthesis method. It has been established that Na3FeTi(PO4)3 forms in the β -phase with hexagonal symmetry (sp. gr. P3¯c ), in contrast to α - Na3Fe2(PO4)3 , which possesses a rhombohedral monoclinic distorted structure. Consequently, β -Na3FeTi(PO4)3 is an ionic conductor and is capable of being easily polarised and exhibiting ionic conductivity. In contrast, α - Na3Fe2(PO4)3 exhibits dielectric properties, as the majority of the cation sublattice is dipole-ordered, whilst the remainder is structurally ordered. The fact that β - Na3FeTi(PO4)3 polycrystals have higher conductivity at room temperature than α - Na3Fe2(PO4)3 suggests that they may be more promising for use as a cathode material.