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硅酸盐通报 ›› 2022, Vol. 41 ›› Issue (9): 3279-3287.

• 陶瓷 • 上一篇    下一篇

Ta、Ba共掺杂石榴石型Li7La3Zr2O12电解质的制备及性能研究

申奥, 周嘉诚, 谢殿臣, 江雪, 马树成, 罗亚历   

  1. 徐州工程学院材料与化学工程学院,徐州 221018
  • 收稿日期:2022-04-17 修回日期:2022-06-22 出版日期:2022-09-15 发布日期:2022-09-27
  • 通讯作者: 罗亚历,博士,讲师。E-mail:yl_luo1125@163.com
  • 作者简介:申 奥(1999—),男。主要从事固体电解质研究。E-mail:948232258@qq.com
  • 基金资助:
    2021年大学生创新训练计划项目(xcx2021016)

Preparation and Properties of Ta, Ba Co-Doped Garnet-Type Li7La3Zr2O12 Electrolyte

SHEN Ao, ZHOU Jiacheng, XIE Dianchen, JIANG Xue, MA Shucheng, LUO Yali   

  1. School of Materials and Chemical Engineering, Xuzhou University of Technology, Xuzhou 221018, China
  • Received:2022-04-17 Revised:2022-06-22 Online:2022-09-15 Published:2022-09-27

摘要: 传统锂离子电池采用有机电解液体系,能量密度难以进一步提升,同时存在一定的安全隐患。采用无机固体电解质构建全固态锂电池,在提高电池能量密度同时可兼顾安全性问题。在众多无机固体电解质中,Li7La3Zr2O12(LLZO)石榴石电解质具有离子电导率高、与金属锂接触稳定等优势,成为受人关注的材料。为了进一步提高该材料的导电性,采用固相法合成Ta、Ba共掺杂LLZO(Li7-x+yLa3-yBayZr2-xTaxO12)电解质,采用X射线衍射、扫描电子显微镜和电化学阻抗法分析样品的物相结构、微观形貌及离子电导率。结果表明,Ta5+掺杂能够稳定立方相结构,Ba2+作为掺杂剂和烧结剂,促进晶粒生长和陶瓷致密化,从而降低总电阻。其中,Li6.45La2.95Ba0.05Zr1.4Ta0.6O12样品在室温下的总电导率为1.07×10-3 S·cm-1,活化能为0.378 eV。Ta5+/Ba2+共掺杂有利于制备高致密度和高电导率的石榴石型电解质材料。

关键词: 固体电解质, 石榴石, Li7La3Zr2O12, 掺杂, 致密度, 电导率

Abstract: Conventional lithium-ion batteries using organic liquid electrolytes suffer from limited energy density and safety risks. To improve energy density and safety, all-solid-state lithium battery are developed using solid electrolytes. Among various inorganic solid-state electrolytes, the garnet-type Li7La3Zr2O12 electrolytes have attracted a great deal of attention, owing to high ionic conductivity and the excellent stability against Li metal. In order to further improve the conductivity, the garnet-type electrolytes Ta and Ba co-doped Li7La3Zr2O12 (Li7-x+yLa3-yBayZr2-xTaxO12) were prepared using solid-state synthesis method. The crystal structure, morphology and ionic conductivity of Li7-x+yLa3-yBayZr2-xTaxO12 (0.4≤x≤0.6, 0≤y≤0.05) electrolytes were systematically investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and electrochemical impedance spectroscopy (EIS), respectively. The results show that Ta5+ doping stabilizes the cubic phase. Meanwhile, Ba2+ as dopand and sintering agent can decrease the total resistance by promoting the growth of grains and ceramic densification. Notably, the Li6.45La2.95Ba0.05Zr1.4Ta0.6O12 sample presents a total conductivity of 1.07×10-3 S·cm-1 at room temperature and an activation energy of 0.378 eV. Ta5+/Ba2+ co-doping strategy is conducive to the preparation of garnet-type electrolyte materials with high density and high conductivity.

Key words: solid-state electrolyte, garnet, Li7La3Zr2O12, doping, density, conductivity

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