Direct Observation of Nucleation and Growth Behaviors of Lithium by In Situ Electron Microscopy
Direct Observation of Nucleation and Growth Behaviors of Lithium by In Situ Electron Microscopy
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DOI：
10.1021/acsenergylett.3c00180
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发表时间：
2023-03
影响因子：
22
通讯作者：
Chunyang Wang;Han Wang;L. Tao;Xinyi Wang;P. Cao;Feng Lin;Huolin L. Xin
中科院分区：
文献类型：
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作者：
Chunyang Wang;Han Wang;L. Tao;Xinyi Wang;P. Cao;Feng Lin;Huolin L. Xin
锂金属阳极是下一代高能量密度锂电池的“圣杯”，但锂金属在纳米尺度上的成核和生长动力学仍然是一个谜。本文通过结合原位电子显微镜和原子模拟，揭示了锂金属在碳上的纳米级成核和生长机制。我们发现，在成核后，锂原子迅速聚集形成液滴状纳米粒子，并倾向于通过扩散介导的融合聚结。统计观测表明，锂的成核遵循混合成核模式，不同于传统的瞬时成核或渐进成核模式。随着颗粒尺寸的增大，液滴状的锂颗粒在表面能最小化的驱动下转变为多面晶体。原子计算表明，大小相关的Li扩散率促进了Li粒子的聚并和形态演化。在沉积过程中，这种液态到固态的转变在剥离后是完全可逆的。这项工作通过揭示支配锂金属成核和生长行为的基本纳米和原子尺度途径，为锂金属的沉积/剥离机制提供了新的见解。
Lithium metal anodes are the “Holy Grail” of next-generation high-energy-density Li batteries, yet the nucleation and growth kinetics of Li metal at the nanoscale still remain a myth. Here, by combiningin situelectron microscopy and atomistic simulations, we decipher the nanoscale nucleation and growth mechanisms of Li metal on carbon. We find that upon nucleation, Li atoms rapidly aggregate to form droplet-shaped nanoparticles that incline to coalesce through diffusion-mediated fusion. Statistical observation shows that the Li nucleation follows a mixed nucleation mode different from conventional instantaneous or progressive nucleation model. With increased particle size, the droplet-like Li particles transform into faceted crystals driven by surface energy minimization. Atomistic calculations reveal that the size-dependent Li diffusivity facilitates the coalescence and morphological evolution of the Li particles. This liquid-to-solid-like transformation during deposition is completely reversible upon stripping. This work, by unraveling the fundamental nano- and atomic-scale pathways dominating Li metal nucleation and growth behaviors, offers new insights into the deposition/stripping mechanism of Li metal.