Abstract Li-garnet Li7La3Zr2O12 (LLZO) is a promising solid electrolyte for lithium metal batteries owing to its excellent stability and high ionic conductivity. However, there exists serious lithium dendrite problem in LLZO electrolyte under elevated current density, easily leading to internal short-circuit and poor cycling performance. In this work, we demonstrated that Ta-doped LLZO with 4 wt% MgO additive delivered superior endurance to lithium dendrite due to its improved mechanical properties and lower electronic conductivity. The critical current density (CCD) of LLZTO-MgO composite electrolyte reached as high as 1.95 mA⸳cm−2 at room temperature (RT). It also realized stable lithium plating/stripping performance for 1000h under 0.5 mA⸳cm−2. Moreover, the full cell paired with LiNi0·6Co0·2Mn0·2O2 cathode exhibited better cycling stability especially at a high rate. Our work provided an alternative strategy for dendrite-suppression in solid electrolyte besides interfacial modification.

中文翻译：

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在掺钽的 Li7La3Zr2O12/MgO 复合电解质中实现高临界电流密度

摘要 锂石榴石 Li7La3Zr2O12 (LLZO) 具有优异的稳定性和高离子电导率，是一种很有前途的锂金属电池固体电解质。然而，LLZO电解液在高电流密度下存在严重的锂枝晶问题，容易导致内部短路和循环性能差。在这项工作中，我们证明了具有 4 wt% MgO 添加剂的 Ta 掺杂 LLZO 由于其改善的机械性能和较低的电子电导率而具有优于锂枝晶的耐久性。LLZTO-MgO 复合电解质的临界电流密度 (CCD) 在室温 (RT) 下高达 1.95 mA⸳cm-2。它还在0.5 mA⸳cm−2下实现了1000小时稳定的锂电镀/剥离性能。而且，与LiNi0·6Co0·2Mn0·2O2正极配对的全电池表现出更好的循环稳定性，尤其是在高倍率下。我们的工作为固体电解质中除界面改性之外的枝晶抑制提供了一种替代策略。