Coefficients of Thermal Expansion of Al- and Y-Substituted NaSICON Solid Solution Na3+2xAlxYxZr2-2xSi2PO12

Resumen

Because of an increasing interest in NaSICON materials as electrolyte materials in all-solid state sodium batteries, their thermal expansion was investigated in this study. The thermal expansion coefficient (CTE) of the Al and Y-substituted NaSICON compositions Na_3+2xAl_xY_xZr_2−2xSi₂PO₁₂ with 0 ≤ x ≤ 0.3 was obtained by dilatometry and compared to the CTE derived from the lattice parameters using high-temperature X-ray diffraction. The difference in CTE obtained from techniques, the influence of sodium content and central metal cation on CTE, as well as other observations such as phase changes are described and rationalized.