We have studied the ionic and thermal transport properties along with the thermodynamic key properties of a Na-ion-conducting phosphate ceramic. The system Na_1+xAl_xTi_2−x(PO₄)₃ (NATP) with x = 0.3 was taken as a NASICON-structured model system which is a candidate material for solid electrolytes in post-Li energy storage. The commercially available powder (NEI Coorp., USA) was consolidated using cold isostatic pressing before sintering. In order to compare NATP with the “classical” NASICON system, Na_1+xZr₂(SiO₄)_x(PO₄)_3−x (NaZSiP) was synthesized with compositions of x = 1.7 and x = 2, respectively, and characterized with regard to their ionic and thermal transport behavior. While ionic conductivity of the NaZSiP compositions was about more than two orders of magnitude higher than in NATP, the thermal conductivity of the NASICON compound showed an opposite behavior. The room temperature value was about a factor two higher in NATP compared to NaZSiP. While the thermal conductivity decreases with increasing temperature in NATP, it increases with increasing temperature in NaZSiP. However, the overall change of this thermal transport parameter over the measured temperature range from room temperature up to 800 °C appeared to be relatively small.

我们研究了离子和热传输特性以及钠离子传导磷酸盐陶瓷的热力学关键特性。系统 Na _1+x Al _x Ti _{2- x} (PO ₄ ) ₃ (NATP) x  = 0.3 作为 NASICON 结构的模型系统，是后锂储能固体电解质的候选材料。市售粉末（NEI Coorp., USA）在烧结前使用冷等静压进行固结。为了将 NATP 与“经典”NASICON 系统进行比较，Na _1+x Zr ₂ (SiO ₄ ) _x (PO ₄ ) _3−x (NaZSiP) 分别以x  = 1.7 和x = 2 的成分合成，并表征了它们的离子和热传输行为。虽然 NaZSiP 组合物的离子电导率比 NATP 高两个数量级以上，但 NASICON 化合物的热导率表现出相反的行为。与 NaZSiP 相比，NATP 的室温值大约高两倍。虽然热导率随着 NATP 中温度的升高而降低，但它随着 NaZSiP 中温度的升高而增加。然而，在从室温到 800 °C 的测量温度范围内，该热传输参数的整体变化似乎相对较小。