Pyrochlore nanocrystals as versatile quasi-single-source precursors to lithium conducting garnets. Issue 34 (12th August 2020)

• Record Type: Journal Article
• Authors: Weller, J. Mark; Chan, Candace K.
• Is Part Of: Journal of materials chemistry. Volume 8:Issue 34(2020)
• Page Start: 17405
• Page End: 17410
• Publication Date: 2020-08-12
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d0ta05842d
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Doped pyrochlore nanocrystal reagents enable new routes to low temperature reactions and dense Li garnet ceramics. Abstract : Lithium conducting garnets are attractive solid electrolytes for solid-state lithium batteries but are difficult to process, generally requiring high reaction and sintering temperatures with long durations. In this work, we demonstrate a synthetic route to obtain Ta-doped garnet (Li6.4 La3 Zr1.4 Ta0.6 O12 ) utilizing La- and Ta-doped lanthanum zirconate (La2.4 Zr1.12 Ta0.48 O7.04 ) pyrochlore nanocrystals as quasi-single-source precursors. Via molten salt synthesis (MSS) in a highly basic flux, the pyrochlore nanocrystals transform to Li-garnet at reaction temperatures as low as 400 °C. We also show that the pyrochlore-to-garnet conversion can take place in one step using reactive sintering, resulting in densified garnet ceramics with high ionic conductivity (0.53 mS cm −1 at 21 °C) and relative density (up to 94.7%). This approach opens new avenues for lower temperature synthesis of lithium garnets using a quasi-single-source precursor and provides an alternative route to highly dense garnet solid electrolytes without requiring advanced sintering processes.