An efficient multi-doping strategy to enhance Li-ion conductivity in the garnet-type solid electrolyte Li7La3Zr2O12. Issue 14 (21st March 2019)

• Record Type: Journal Article
• Authors: Meesala, Yedukondalu; Liao, Yu-Kai; Jena, Anirudha; Yang, Nai-Hsuan; Pang, Wei Kong; Hu, Shu-Fen; Chang, Ho; Liu, Chia-Erh; Liao, Shih-Chieh; Chen, Jin-Ming; Guo, Xiangxin; Liu, Ru-Shi
• Is Part Of: Journal of materials chemistry. Volume 7:Issue 14(2019)
• Page Start: 8589
• Page End: 8601
• Publication Date: 2019-03-21
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c9ta00417c
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : A systematic multi-doping strategy to enhance Li-ion conductivity of the garnet-type Li7 La3 Zr2 O12 by doping Ga(iii ) Ba(ii ) and Ta(v ) ions into the garnet framework. Abstract : Lithium-ion (Li + ) batteries suffer from problems caused by the chemical instability of their organic electrolytes. Solid-state electrolytes that exhibit high ionic conductivities and are stable to lithium metal are potential replacements for flammable organic electrolytes. Garnet-type Li7 La3 Zr2 O12 is a promising solid-state electrolyte for next-generation solid-state Li batteries. In this study, we prepared mono-, dual-, and ternary-doped lithium (Li) garnets by doping tantalum (Ta), tantalum–barium (Ta–Ba), and tantalum–barium–gallium (Ta–Ba–Ga) ions, along with an undoped Li7 La3 Zr2 O12 (LLZO) cubic garnet electrolyte, using a conventional solid-state reaction method. The effect of multi-ion doping on the Li + dynamics in the garnet-type LLZO was studied by combining joint Rietveld refinement against X-ray diffraction and high-resolution neutron powder diffraction analyses with the results of Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and multinuclear magic angle spinning nuclear magnetic resonance. Our results revealed that Li + occupancy in the tetrahedrally coordinated site (24d) increased with increased multi-ion doping in LLZO, whereas Li + occupancy in the octahedrally coordinated site (96h) remained constant. Among the investigated compounds, the ternary-doped garnet structure Li6.65 Ga0.05 La2.95 Ba0.05 Zr1.75 Ta0.25 O12 (LGLBZTO) exhibited the highest total ionic conductivity of 0.72 and 1.24 mS cm −1 at room temperature and 60 °C, respectively. Overall, our findings revealed that the dense microstructure and increased Li + occupancy in the tetrahedral-24dLi1 site played a key role in achieving the maximum room-temperature Li-ion conductivity in the ternary-doped LGLBZTO garnet, and that the prepared ternary-doped LGLBZTO was a potential solid electrolyte for Li-ion batteries without polymer adhesion.