Ce_0.8Sm_0.2O_1.9-Zr₂WP₂O₁₂复合电解质的制备及热膨胀性能研究

Study on Preparation and Thermal Expansion Properties of Ce_0.8Sm_0.2O_1.9-Zr₂WP₂O₁₂ Composite Electrolyte

通过固相反应法分别在不同的烧结温度制备了一类新型的SZ05 (Ce0.8Sm0.2O1.9和Zr2WP2O12质量比1:1)复合电解质材料,并通过Raman和XRD分析了烧结温度对SZ05复合电解质的相成分的影响。Raman和XRD分析结果表明:900℃及以上烧结的SZ05复合电解质的Raman和XRD谱出现了新的特征峰,说明发生了相变。800℃以下(包括800℃)烧结的SZ05复合电解质的Raman特征峰和XRD特征峰均由纯SDC和ZWP的特征峰组成,没有第三相特征峰,与未烧结前的SZ05复合材料特征峰完全一致。考虑到随着烧结温度降低复合材料的致密度下降,氧离子迁移过程的势垒变大,因此SZ05复合电解质的最佳烧结条件是800℃左右。本文又分析了不同烧结温度下制备的SZ05复合电解质的热膨胀系数。SZ05复合电解质的热膨胀系数均低于纯SDC的热膨胀系数,尽管SZ05复合电解质的热膨胀系数受到样品致密度的影响,但结合XRD和Raman谱的分析结果,600℃~800℃烧结的SZ05复合电解质与纯SDC相比热膨胀系数的下降还有很大一部分贡献来自于复合材料中ZWP的负热膨胀性。SZ05复合电解质与纯SDC相比热膨胀系数下降表明Ce0.8Sm0.2O1.9(SDC)与Zr2WP2O12的复合实现了对SDC电解质热膨胀系数调控的目的。

A new type of SZ05 (Ce0.8Sm0.2O1.9 and Zr2WP2O12 mass ratio of 1:1) composite electrolyte materials were prepared by solid state reaction method at different sintering temperatures, and the effect of the sintering temperature of SZ05 composite on the phase composition of the electrolyte was analyzed by Raman and XRD. Raman and XRD analysis results show that Raman and XRD spectra of SZ05 composite electrolyte sintered at 900˚C and above showed new characteristic peaks, indicating that a phase change occurred. Raman and XRD characteristic peak of SZ05 composite electrolyte sintered below 800˚C (including 800˚C) are composed of pure SDC and ZWP characteristic peaks, and there is no third phase characteristic peak, which is completely the same as that of unsintered SZ05 composite material. Considering that as the sintering temperature de-creases, the density of the composite material decreases and the migration barrier of the oxygen ion becomes larger. Therefore, the optimal sintering condition for the SZ05 composite electrolyte is about 800˚C. In this paper, the thermal expansion coefficient of SZ05 composite electrolyte pre-pared at different sintering temperatures is analyzed. The thermal expansion coefficient of SZ05 composite electrolyte is lower than that of pure SDC;Although the thermal expansion coefficient of SZ05 composite electrolyte is affected by the density of the sample. According to the analysis results of XRD and Raman spectrum, the decrease in thermal expansion coefficient of 600˚C^800˚C sintered SZ05 composite electrolyte in contrast to pure SDC mainly comes from the negative thermal expansion of ZWP in the composite. The decrease in thermal expansion coefficient of SZ05 composite electrolyte compared with pure SDC indicates that the combination of Ce0.8Sm0.2O1.9 (SDC) and Zr2WP2O12 achieves the purpose of regulating the thermal expansion coefficient of SDC electrolyte.