锶锌双掺杂磷灰石型硅酸镧电解质的制备与表征

Preparation and Characterization of Strontium and Zinc Doped Apatite Lanthanum Silicate Electrolyte

为了提升硅酸镧电解质在中低温时(500~800℃)的电导率,将氧化镧、正硅酸四乙酯与掺杂元素的氧化物做为主要原料,通过溶胶-凝胶法制备了锶、锌双掺杂的磷灰石型硅酸镧电解质材料La9.33SrxSi5ZnO25+x,采用X射线衍射、傅里叶变换红外光谱仪、扫描电子显微镜和变温介电测量系统对样品的物相、微观结构和电导率进行表征。结果表明锶和锌成功进入硅酸镧晶格中,且对晶体的结构与形貌影响较小,以掺量和烧结温度做为变量的研究显示,当Sr的掺量为0.2、Zn的掺量为1、烧结温度为1400℃时,所得到的电学性能最佳,其在800℃下的离子电导率达5.43×10^-3S/cm,相较未掺杂的磷灰石型硅酸镧固体电解质的电导率1.7×10^-3S/cm有一定提高。

To increase the conductivity of lanthanum electrolyte at the temperatures of 500-800 ℃,the electrolyte of Sr and Zn double doped La9.33SrxSi5ZnO25+x was prepared by sol-gel method using La2O3, SrO, ZnO and tetraethoxysilane as raw materials. The phase, microstructure and conductivity of the samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy,scanning electron microscopy and variable temperature dielectric measurement system. The results show that Sr and Zn successfully enter the lattice of lanthanum silicate, wielding little influence on the crystal structure and morphology. The maximum ionic conductivity of La9.33SrxSi5ZnO25+x is 5.43×10^-3 S/cm in 0.2 mole ratio of Sr doping at 800 ℃, which is higher than un-doped La9.33Si6O26 ionic conductivity, and the best sintering temperature for La9.33Sr0.2Si5ZnO25.2 electrolyte is 1 400 ℃.