A New General Paradigm for Understanding and Preventing Li Metal Penetration through Solid Electrolytes
A New General Paradigm for Understanding and Preventing Li Metal Penetration through Solid Electrolytes
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DOI：
10.1016/j.joule.2020.10.009
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发表时间：
2020-11
期刊：
影响因子：
39.8
通讯作者：
Y. Qi;C. Ban;S. Harris
中科院分区：
文献类型：
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作者：
Y. Qi;C. Ban;S. Harris
锂（Li）或钠（Na）金属阳极与高离子传导性固体电解质（SE）一起使用可以为电池提供体积和重量能量密度的阶跃改进。不幸的是，这些SE面临着重大的技术挑战，这在很大程度上是因为Li和Na枝晶可以穿透SE，导致短路。从锂电池领域广泛使用的模型的角度来看，这种软材料（Li或Na金属）穿透陶瓷的能力是令人惊讶的。我们介绍了一种电池领域的新概念，通过将SE表面置于残余压应力状态来防止锂枝晶穿透SE。对于足够高的压缩应力，裂纹难以形成，并且确实形成的裂纹被迫闭合，从而抑制枝晶穿透。这种方法广泛用于解决商业上重要的金属应力腐蚀开裂问题和陶瓷和玻璃中的静态疲劳问题（例如，Gorilla Glass）。然而，如果当SE处于压缩状态时，通过SE的Li离子传输速率显著降低，则该技术将不适用于SE。我们的分子动力学计算锂离子运输通过一个共同的SE表明，即使是非常高的残余压应力（10GPa）的引入只有适度的影响锂离子运输动力学，这表明这种方法是可行的，并能够提供一个新的范例，开发高性能和机械稳定的SE。
The use of lithium (Li) or sodium (Na) metal anodes together with highly ion-conductive solid electrolytes (SEs) could provide batteries with a step improvement in volumetric and gravimetric energy densities. Unfortunately, these SEs face significant technical challenges, in large part because Li and Na dendrites can penetrate through SEs, leading to short circuits. The ability of such a soft material (Li or Na metal) to penetrate through ceramic is surprising from the point of view of models widely used in the Li-battery field.We introduce a concept, new to the battery field, for preventing penetration of lithium dendrites through SEs by putting the SE surfaces into a state of residual compressive stress. For a sufficiently high compressive stress, cracks have difficulty forming, and cracks that do form are forced to close, inhibiting dendrite penetration. This approach is widely used to solve commercially important stress corrosion cracking problems in metals and static fatigue problems in ceramics and glasses (e.g., Gorilla Glass). However, the technique will not be useful for SEs if the Li-ion transport rate through a SE is substantially reduced when the SE is under compression. Our molecular dynamics calculations for Li-ion transport through a common SE demonstrate that the introduction of even very high residual compressive stresses (∼10 GPa) has only a modest effect on Li-ion transport kinetics, suggesting that this approach is viable and capable of providing a new paradigm for developing high-performance and mechanically stable SEs.