Abstract：
Cation-doped cubic Li7La3Zr2O12 is regarded as a promising solid electrolyte for safe and energy-dense solid-state lithium batteries. However, it suffers from the formation of Li2CO3 and high electronic conductivity, which give rise to an unconformable Li/Li7La3Zr2O12 interface and lithium dendrites. Herein, composite AlF3-Li6.4La3Zr1.4Ta0.6O12 solid electrolytes were created based on thermal AlF3 decomposition and F/O displacement reactions under a high-temperature sintering process. When the AlF3 is thermally decomposed, it leaves Al2O3/AlF3 meliorating the grain boundaries and F- ions partially displacing O2- ions in the grains. Due to the higher electronegativity of F- in the grains and the grain-boundary modification, these AlF3-Li6.4La3Zr1.4Ta0.6O12 deliver optimized electronic conduction and chemical stability against the formation of Li2CO3. The Li/AlF3-Li6.4La3Zr1.4Ta0.6O12/Li cell exhibits a low interfacial resistance of ∼16 Ω cm2 and an ultrastable long-term cycling behavior for 800 h under a current density of 200 μA/cm2, leading to Li//LiCoO2 solid-state batteries with good rate performance and cycling stability.
摘要：
阳离子掺杂的立方Li7La3Zr2O12被认为是一种有前途的固体电解质，用于安全且能量密集的固态锂电池。然而,它受到Li2CO3的形成和高电子电导率的影响，导致Li/Li7La3Zr2O12界面和锂枝晶不一致。在这里，复合AlF3-Li6.4La3Zr1.4Ta0.6O12固体电解质是基于高温烧结过程中的AlF3热分解和F/O置换反应而产生的。当AlF3热分解时，它留下Al2O3/AlF3改善了晶界，F-离子部分取代了晶粒中的O2-离子。由于晶粒中F-的较高电负性和晶界改性，这些AlF3-Li6.4La3Zr1.4Ta0.6O12提供优化的电子传导和化学稳定性，防止Li2CO3的形成。Li/AlF3-Li6.4La3Zr1.4Ta0.6O12/Li电池具有〜16Ωcm2的低界面电阻，并且在200μA/cm2的电流密度下具有800小时的超稳定长期循环行为，导致Li//LiCoO2固态电池具有良好的倍率性能和循环稳定性。
