Complex admittance measurements were performed on α-NaFeO2, and on the product, Na0.9FeO2, which was obtained by Na extraction. Both specimens were polycrystalline powders. The conductivity in both cases was assumed to be due to Na ions which hopped between octahedral positions via the adjacent empty tetrahedral positions which were characteristic of the rock-salt framework. The parent material exhibited an activation energy, for direct-current conductivity, of 0.31eV between 306 and 498K. The removal of Na, in spite of creating octahedral vacancies, resulted in a lower conductivity and a higher activation energy (0.58eV) over a similar temperature range.

α-NaFeO2 - Ionic Conductivity and Sodium Extraction. M.C.Blesa, E.Moran, C.Leon, J.Santamaria, J.D.Tornero, N.Menendez: Solid State Ionics, 1999, 126[1-2], 81-7