Sintering, micro-structure and Li+ conductivity of Li7−xLa3Zr2−xNbxO12/MgO (x = 0.2–0.7) Li-Garnet composite ceramics. Issue 1 (January 2019)

• Record Type: Journal Article
• Authors: Huang, Xiao; Song, Zhen; Xiu, Tongping; Badding, Michael E.; Wen, Zhaoyin
• Is Part Of: Ceramics international. Volume 45:Issue 1(2019)
• Page Start: 56
• Page End: 63
• Publication Date: 2019-01
• Subjects: Li-Garnet -- c-LLZO -- Solid electrolyte -- Nb-doping -- High conductivity -- Sintering; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2018.09.133
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Nb-doped Li7 La3 Zr2 O12 (Nb-LLZO) is one of the promising electrolyte candidates in the Li-Garnet family due to its high Li-ion conductivity. The sintered Nb-LLZO ceramics, however, often exhibit abnormal grain growth with high porosity and poor mechanical properties. For advantaged electrochemical and mechanical properties, a uniform and dense microstructure is desired. In this research, MgO has been added as a secondary phase to inhibit abnormal grain growth in Nb-LLZO. The sintering process of the Nb-LLZO/MgO composite ceramics has been studied for different Nb doping levels (0.2–0.7 pfu) at sintering conditions of 1250 °C for 1–360 min. The ceramic density, microstructure, and Li-ion conductivity are reported. The composite ceramics have shown a very fast sintering speed. At 1250 °C, the 0.4Nb-LLZO/MgO composite can be well-sintered in 1 min. For sintering at 1250 °C for 40 min, ceramic samples showing relative density of 97%, conductivity of 6 × 10 −4 S cm −1 at 25 °C, and activation energy of 0.40 eV are obtained.