Characterization of the Transport Properties and of the Formation and Growth Mechanims of the Solid Electrolyte Interphase (SEI) on Carbon Model-Type Electrodes

碳模型型电极上固体电解质界面相 (SEI) 的输运特性以及形成和生长机制的表征

• 批准号: 465281402
• 负责人: Professor Dr. Andreas Bund
• 金额: --
• 依托单位: Fachgebiet Elektrochemie und Galvanotechnik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/465281402?language=en
• 关键词: Characterization; Transport; Properties; Formation; Growth

The solid electrolyte interphase (SEI) plays an important role for the performance of lithium-ion batteries. The SEI is a passivation layer on top of the graphite active material particles of the negative electrode, which is formed during the first charging cycle of the battery and which prevents further decomposition of the electrolyte by the lithiated graphite. During battery production, the SEI has to be formed very slowly in order to achieve good SEI properties. This time-consuming process contributes significantly to the battery production costs. Furthermore, the ageing the SEI during the further charging/discharging of the battery reduces the cycle life. Despite the important role of the SEI, the transport mechanisms of Li+ ions, molecules, and electrons across the SEI and the related formation and growth mechanisms of the SEI are not well understood. An ideal SEI would allow for fast Li+ ion transport, but would block electrons and molecules completely. However, real SEI allow for a slow transport of molecules and/or electrons across the SEI, which leads to SEI ageing. In this project, we will use a number of carefully chosen complementary experimental techniques to elucidate the relations between formation conditions of the SEI, formation and growth kinetics, chemical and morphological properties, mechanical properties, as well as transport properties. To this end, we will grow model-type SEIs on well-defined carbon electrodes, namely on glassy carbon electrodes, sputtered carbon electrodes and high-oriented pyrolytic graphite (HOPG) electrodes in contact to carbonate-based electrolytes. We will use galvanostatic protocols for SEI formation in order to alter the SEI properties by varying the formation current density. Our results will contribute to the development of improved SEI models. To this end, we will collaborate with a group in the field of electrochemical multiphysics modeling.

固体电解质界面（SEI）对于锂离子电池的性能起着重要作用。 SEI 是负极石墨活性材料颗粒顶部的钝化层，在电池的第一次充电循环期间形成，可防止锂化石墨进一步分解电解质。在电池生产过程中，SEI 必须非常缓慢地形成，才能获得良好的 SEI 性能。这一耗时的过程极大地增加了电池的生产成本。此外，在电池的进一步充电/放电过程中SEI的老化会缩短循环寿命。尽管SEI发挥着重要作用，但Li+离子、分子和电子穿过SEI的传输机制以及SEI的相关形成和生长机制尚不清楚。理想的 SEI 将允许快速 Li+ 离子传输，但会完全阻止电子和分子。然而，真正的 SEI 允许分子和/或电子在 SEI 上缓慢传输，这会导致 SEI 老化。在这个项目中，我们将使用许多精心选择的补充实验技术来阐明SEI的形成条件、形成和生长动力学、化学和形态特性、机械特性以及传输特性之间的关系。为此，我们将在明确的碳电极上生长模型型SEI，即在与碳酸盐基电解质接触的玻碳电极、溅射碳电极和高取向热解石墨（HOPG）电极上。我们将使用恒电流协议进行 SEI 形成，以便通过改变形成电流密度来改变 SEI 特性。我们的结果将有助于改进 SEI 模型的开发。为此，我们将与电化学多物理场建模领域的一个小组合作。