Pyrochlore nanocrystals as versatile quasi-single-source precursors to lithium conducting garnets
Pyrochlore nanocrystals as versatile quasi-single-source precursors to lithium conducting garnets
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DOI：
10.1039/d0ta05842d
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发表时间：
2020-09
影响因子：
--
通讯作者：
J. Weller;Candace K. Chan
中科院分区：
文献类型：
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作者：
J. Weller;Candace K. Chan
锂传导石榴石是固态锂电池有吸引力的固体电解质，但难以加工，通常需要高的反应和烧结温度以及长时间。在这项工作中，我们展示了一种合成路线，利用镧和钽掺杂的锆酸镧（La2.4Zr1.12Ta0.48O7.04）烧绿石纳米晶体作为准单源前驱体来获得钽掺杂的石榴石（Li6.4La3Zr1.4Ta0.6O12）。通过在高碱性熔剂中的熔盐合成（MSS），烧绿石纳米晶体在低至400°C的反应温度下转变为锂石榴石。我们还表明，使用反应烧结，烧绿石到石榴石的转化可以一步完成，从而得到具有高离子电导率（21°C时为0.53 mS cm−1）和相对密度（高达94.7%）的致密石榴石陶瓷。这种方法为使用准单源前驱体低温合成锂石榴石开辟了新途径，并为无需先进烧结工艺制备高密度石榴石固体电解质提供了一种替代路线。
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 (Li6.4La3Zr1.4Ta0.6O12) utilizing La- and Ta-doped lanthanum zirconate (La2.4Zr1.12Ta0.48O7.04) 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.