We have measured the effect of varying the mobile ion concentration on the sodium ion conductivity in the Hf-Nasicon system, Na1+xHf2SixP3-xO12, for 1.4 ≤ x ≤ 2.8. The conductivity is greatest for Na3.2Hf2Si2.2 P0.8O12: σ25°C = 2.3 × 10-3 (ω cm)-1, and σ250°C = 1.7 × 10-1 (ω cm)-1. These values are approximately 50% greater and worse, respectively, than the values reported for the best Zr-Nasicon. We have characterized the variation of lattice parameters with composition and found the behavior to be similar to that of Zr-Nasicon. A small distortion from rhombohedral to monoclinic symmetry occurs for compositions 1.8 ≤ x ≤ 2.2.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics