锆位掺杂锆酸镧锂固体电解质溶胶凝胶法制备及性能研究
发布时间：2018-10-23 10:39
【摘要】：随着社会经济的快速发展,锂离子电池已广泛应用于各个方面。在锂电池大量使用的过程中,由液态电解质引发的易燃、易爆等安全隐患是目前亟待解决的问题。针对这一问题,人们提出了全固态锂离子电池的概念。固体电解质是全固态电池的重要组成部分。其中,具有类石榴石型晶体结构的固体电解质Li7La3Zr2O12(简称LLZO)具有较高的室温离子电导率、较好的电化学和化学稳定性、环境污染小、易制备、成本低等优点,是一种很有应用前景的固体电解质材料。本文以石榴石结构的LLZO固体电解质为研究对象,采用溶胶凝胶法分别制备了Mn4+掺杂的LLZO和Mo6+掺杂的LLZO,并使用X射线衍射仪、阿基米德排水法、扫描电子显微镜、交流阻抗谱等测试方法对所得样品进行结构及性能表征。主要研究内容如下:采用溶胶凝胶法在900℃保温6h合成粉体Li7La3Zr2-xMnx O12(x=0、0.01、0.03、0.05、0.07),在1115℃保温3h烧结得到Li7La3Zr2-xMnxO12(0≤x≤0.07)陶瓷样品。X射线衍射结果表明,所有合成的陶瓷样品均为立方相与四方相的混合相。Li7La3Zr1.97Mn0.03O12陶瓷样品的相对致密度高达94%。Li7La3Zr1.97Mn0.03O12的导电性能最优,总的离子电导率为9.71×10-5S/cm,总锂离子迁移激活能为0.33eV。采用溶胶凝胶法在750℃保温6h合成Li7-2xLa3Zr2-xMoxO12(x=0、0.05、0.10、0.20、0.30)粉体,并在1100℃保温3h烧结得到Li7-2xLa3Zr2-xMoxO12(0≤x≤0.30)陶瓷样品。粉末XRD数据表明x≥0.10时,粉体在750℃保温6h生成立方相结构。陶瓷样品测得的XRD数据结果显示,未掺杂的LLZO呈立方相与四方相的混合相结构。掺杂量x≥0.05时,样品的晶体结构由混合相转变为立方相结构。Mo的掺杂使晶粒尺寸逐渐减小,颗粒大小分布均匀,气孔减少,陶瓷样品的致密度增加。掺杂量为x=0.20的样品的致密度高达92.8%。掺杂量为x=0.20的样品导电性能最佳,总的离子电导率为5.09×10-4S/cm,对应激活能为0.29eV。相比固相法,溶胶凝胶法在较低的温度下合成具有立方相结构的Mo掺杂的LLZO并提高其离子电导率。
[Abstract]:With the rapid development of social economy, lithium ion battery has been widely used in various fields. In the process of mass use of lithium-ion batteries, the safety problems such as flammability and explosive caused by liquid electrolytes are urgent problems to be solved. To solve this problem, the concept of all solid state lithium ion battery is proposed. Solid electrolyte is an important part of all solid state battery. Among them, the solid electrolyte Li7La3Zr2O12 (LLZO) with garnet crystal structure has the advantages of high ionic conductivity at room temperature, good electrochemical and chemical stability, low environmental pollution, easy preparation and low cost. It is a promising solid electrolyte material. In this paper, LLZO solid electrolyte with garnet structure was studied. Mn4 doped LLZO and Mo6 doped LLZO, were prepared by sol-gel method. X-ray diffractometer, Archimedes drainage method, scanning electron microscope (SEM) were used. The structure and properties of the samples were characterized by AC impedance spectroscopy. The main contents of the study are as follows: the powder Li7La3Zr2-xMnx O12 was synthesized by sol-gel method at 900 鈩，
本文编号：2288990
[Abstract]:With the rapid development of social economy, lithium ion battery has been widely used in various fields. In the process of mass use of lithium-ion batteries, the safety problems such as flammability and explosive caused by liquid electrolytes are urgent problems to be solved. To solve this problem, the concept of all solid state lithium ion battery is proposed. Solid electrolyte is an important part of all solid state battery. Among them, the solid electrolyte Li7La3Zr2O12 (LLZO) with garnet crystal structure has the advantages of high ionic conductivity at room temperature, good electrochemical and chemical stability, low environmental pollution, easy preparation and low cost. It is a promising solid electrolyte material. In this paper, LLZO solid electrolyte with garnet structure was studied. Mn4 doped LLZO and Mo6 doped LLZO, were prepared by sol-gel method. X-ray diffractometer, Archimedes drainage method, scanning electron microscope (SEM) were used. The structure and properties of the samples were characterized by AC impedance spectroscopy. The main contents of the study are as follows: the powder Li7La3Zr2-xMnx O12 was synthesized by sol-gel method at 900 鈩，
本文编号：2288990
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