High electronic conductivity as the origin of lithium dendrite formation within solid electrolytes
High electronic conductivity as the origin of lithium dendrite formation within solid electrolytes
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DOI：
10.1038/s41560-018-0312-z
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发表时间：
2019-03-01
期刊：
影响因子：
56.7
通讯作者：
Wang, Chunsheng
中科院分区：
文献类型：
--
作者：
Han, Fudong;Westover, Andrew S.;Wang, Chunsheng
固体电解质（SE）被广泛认为是高能电池锂阳极的“推动者”。然而，最近的报道表明，在Li 7 La 3 Zr 2 O 12（LLZO）和Li 2S-P2 S5中的Li枝晶形成实际上比在锂电池的液体电解质中的Li枝晶形成容易得多，其机制仍然难以捉摸。在这里，我们说明了枝晶形成的起源，通过监测锂浓度分布在三个流行的，但有代表性的SE（LiPON，LLZO和无定形Li 3 PS4）在锂电镀过程中使用时间分辨的操作中子深度剖析的动态演变。虽然没有明显的变化，在LiPON中的锂浓度可以观察到，我们可视化内的散装LLZO和Li 3 PS4的Li的直接沉积。我们的研究结果表明，LLZO和Li 3 PS4的高电子电导率是主要负责这些SE中的枝晶形成。因此，降低电子电导率，而不是进一步提高SE的离子电导率，对于全固态锂电池的成功至关重要。
Solid electrolytes (SEs) are widely considered as an 'enabler' of lithium anodes for high-energy batteries. However, recent reports demonstrate that the Li dendrite formation in Li7La3Zr2O12 (LLZO) and Li2S-P2S5 is actually much easier than that in liquid electrolytes of lithium batteries, by mechanisms that remain elusive. Here we illustrate the origin of the dendrite formation by monitoring the dynamic evolution of Li concentration profiles in three popular but representative SEs (LiPON, LLZO and amorphous Li3PS4) during lithium plating using time-resolved operando neutron depth profiling. Although no apparent changes in the lithium concentration in LiPON can be observed, we visualize the direct deposition of Li inside the bulk LLZO and Li3PS4. Our findings suggest the high electronic conductivity of LLZO and Li3PS4 is mostly responsible for dendrite formation in these SEs. Lowering the electronic conductivity, rather than further increasing the ionic conductivity of SEs, is therefore critical for the success of all-solid-state Li batteries.