Risse Sebastian, Härk Eneli, Kent Ben, Ballauff Matthias
Institute for Soft Matter and Functional Materials , Helmholtz-Zentrum Berlin für Materialien und Energie , Hahn Meitner Platz 1 , 14109 Berlin , Germany.
Institute of Physics , Humboldt-University Berlin , Unter den Linden 6 , 10099 Berlin , Germany.
ACS Nano. 2019 Sep 24;13(9):10233-10241. doi: 10.1021/acsnano.9b03453. Epub 2019 Sep 3.
This study reports the use of small-angle neutron scattering to investigate processes in an operating Li/S battery. The combination with impedance spectroscopy yields valuable insights into the precipitation and dissolution of lithium sulfide during 10 cycles of galvanostatic cycling. The use of a deuterated electrolyte increases strongly the sensitivity to detect the sulfur and LiS precipitates at the carbon host electrode and allows us to observe the time-dependent initial wetting of the system. No correlation of the scattering signal of the micropores with either lithium sulfide or sulfur is observable during the whole course of the experiment. Hence both reaction products do not precipitate inside the microporous structure but on the outer surface of the micrometer-sized carbon fibers used in this study. The excellent scattering contrast allows a detailed analysis of the formation and dissolution process of nanoscopic LiS structures. While lithium sulfide particles grow homogeneously during the precipitation period, smaller LiS particles dissolve first followed by a sudden dissolution of the larger LiS particles.
本研究报告了利用小角中子散射来研究运行中的锂硫电池中的过程。与阻抗谱相结合,能深入了解恒电流循环10个周期过程中硫化锂的沉淀和溶解情况。使用氘代电解质大大提高了在碳宿主电极处检测硫和硫化锂沉淀的灵敏度,并使我们能够观察到系统随时间的初始润湿情况。在整个实验过程中,未观察到微孔的散射信号与硫化锂或硫之间存在相关性。因此,两种反应产物均不在微孔结构内部沉淀,而是在本研究中使用的微米级碳纤维的外表面沉淀。出色的散射对比度使得能够对纳米级硫化锂结构的形成和溶解过程进行详细分析。在沉淀期,硫化锂颗粒均匀生长,较小的硫化锂颗粒先溶解,随后较大的硫化锂颗粒突然溶解。