Institute of Material Science and Technologies, Technical University Berlin , Strasse des 17. Juni 135, 10623 Berlin, Germany.
Helmholtz Centre Berlin for Materials and Energy Hahn-Meitner-Platz 1, 14109 Berlin, Germany.
ACS Nano. 2016 Aug 23;10(8):7990-7. doi: 10.1021/acsnano.6b03939. Epub 2016 Aug 1.
Due to its low redox potential and high theoretical specific capacity, Li metal has drawn worldwide research attention because of its potential use in next-generation battery technologies such as Li-S and Li-O2. Unfortunately, uncontrollable growth of Li microstructures (LmSs, e.g., dendrites, fibers) during electrochemical Li stripping/plating has prevented their practical commercialization. Despite various strategies proposed to mitigate LmS nucleation and/or block its growth, a fundamental understanding of the underlying evolution mechanisms remains elusive. Herein, synchrotron in-line phase contrast X-ray tomography was employed to investigate the morphological evolution of electrochemically deposited/dissolved LmSs nondestructively. We present a 3D characterization of electrochemically stripped Li electrodes with regard to electrochemically plated LmSs. We clarify fundamentally the origin of the porous lithium interface growing into Li electrodes. Moreover, cleavage of the separator caused by growing LmS was experimentally observed and visualized in 3D. Our systematic investigation provides fundamental insights into LmS evolution and enables us to understand the evolution mechanisms in Li electrodes more profoundly.
由于其较低的氧化还原电位和较高的理论比容量，金属锂因其在下一代电池技术（如锂硫和锂氧）中的潜在应用而引起了全球研究关注。不幸的是，在电化学锂剥离/电镀过程中，锂微结构（例如枝晶、纤维）的不可控生长阻碍了其实际的商业化应用。尽管已经提出了各种策略来减轻锂微结构的成核和/或阻止其生长，但对其潜在的演化机制仍缺乏基本的认识。本文采用同步辐射原位相衬 X 射线断层扫描技术对电化学沉积/溶解的锂微结构进行了非破坏性的形态演化研究。我们对电化学剥离的锂电极进行了三维特征分析，以了解电化学电镀的锂微结构。我们从根本上阐明了多孔锂界面在生长进入锂电极过程中的成因。此外，我们还在三维空间中观察到并可视化了由于锂微结构生长导致的隔离器的破裂。我们的系统研究为锂微结构的演化提供了基本的认识，并使我们能够更深入地理解锂电极中的演化机制。
