Ultrafast deposition of faceted lithium polyhedra by outpacing SEI formation
Ultrafast deposition of faceted lithium polyhedra by outpacing SEI formation
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DOI：
10.1038/s41586-023-06235-w
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发表时间：
2023-08
期刊：
影响因子：
64.8
通讯作者：
Xintong Yuan;Bo Liu;M. Mecklenburg;Yuzhang Li
中科院分区：
文献类型：
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作者：
Xintong Yuan;Bo Liu;M. Mecklenburg;Yuzhang Li
锂（Li）金属的电沉积对于高能电池是至关重要的。然而，同时形成的表面腐蚀膜称为固体电解质界面（SEI）复杂的沉积过程，这巩固了我们对锂金属电沉积的理解不足。在这里，我们通过在超快沉积电流密度下超过SEI形成来解耦这两个交织的过程，同时还避免了质量传输限制。通过使用低温电子显微镜，，-，我们发现的内在的沉积形态的金属锂是一个菱形十二面体，这是令人惊讶的独立的电解质化学或集电器基板。在纽扣电池架构中，这些菱形十二面体表现出与集电器的近点接触连接性，这可以加速非活性Li的形成。我们提出了一种脉冲电流协议，通过利用Li菱形十二面体作为成核种子来克服这种故障模式，从而使后续的致密Li生长能够与基线相比提高电池性能。虽然Li沉积和SEI形成在过去的研究中一直紧密相关，但我们的实验方法为从根本上理解这些相互分离的过程提供了新的机会，并为设计更好的电池带来了新的见解。
Electrodeposition of lithium (Li) metal is critical for high-energy batteries. However, the simultaneous formation of a surface corrosion film termed the solid electrolyte interphase (SEI) complicates the deposition process, which underpins our poor understanding of Li metal electrodeposition. Here we decouple these two intertwined processes by outpacing SEI formation at ultrafast deposition current densities while also avoiding mass transport limitations. By using cryogenic electron microscopy, , –, we discover the intrinsic deposition morphology of metallic Li to be that of a rhombic dodecahedron, which is surprisingly independent of electrolyte chemistry or current collector substrate. In a coin cell architecture, these rhombic dodecahedra exhibit near point-contact connectivity with the current collector, which can accelerate inactive Li formation. We propose a pulse-current protocol that overcomes this failure mode by leveraging Li rhombic dodecahedra as nucleation seeds, enabling the subsequent growth of dense Li that improves battery performance compared with a baseline. While Li deposition and SEI formation have always been tightly linked in past studies, our experimental approach enables new opportunities to fundamentally understand these processes decoupled from each other and bring about new insights to engineer better batteries.