Exploring Interfaces in Li-ion All-Solid-State Batteries

向可再生能源的必要过渡要求开发安全、可靠和具有成本效益的能源储存系统。然而，占主导地位的商用锂电池通常基于易燃和/或有毒的液体电解液(充放电过程中传输锂离子的介质)。目前标准的一个有前途的替代方案是固体电解液(Ses)，它的使用将导致全固态电池(ASSB)。与液体同类产品不同，SE不会构成同样的易燃性和毒性风险。到目前为止，人们对锂离子在固体电解质中迁移等参数的化学机理、合成和操作过程中活性材料及其界面形成的结构和组成以及起始材料的微观性质如何影响电化学性能知之甚少。本研究的主要目的是深入了解ASSB中界面的反应机理，以提高其性能。我们将专注于由活性材料(可以存储锂并因此存储能量)和SES组成的现实混合物，而不仅仅是纯材料。我们的目标是使用粉末X射线衍射、固体核磁共振光谱和电子显微镜在分子水平上深入了解ASSB在合成和操作过程中与结构和动态变化相关的化学机制。对这些机制的了解将导致优化的ASSB具有更好的容量保留、充电率和寿命。

The necessary transition towards renewable energy resources requires the development of safe, reliable, and cost-efficient energy storage systems. However, the dominating commercial lithium batteries are usually based on liquid electrolytes (media that transports lithium ions during charge and discharge) that are flammable and/or toxic.One promising alternative to the current standard are solid electrolytes (SEs), the use of which would result in All-Solid-State Batteries (ASSBs). Unlike their liquid counterparts, SEs do not pose the same flammability and toxicity risks. To date, only little is known about the chemical mechanisms that underpin parameters such as Li-ion transport in solid electrolytes, the structures and compositions formed both in the active materials and their interfaces during synthesis and operation, and how the microscopic properties of the starting materials influence the electrochemical performance.The main goal of the research project is to provide insight into the reaction mechanisms at the interfaces within an ASSB in order to improve their performance. We will focus on realistic mixtures consisting of active materials (that can store lithium and thus energy) and SEs instead of only pure materials. We aim to use powder X-ray diffraction, solid state NMR spectroscopy, and electron microscopy to provide molecular-level insight into the chemical mechanisms related to structural and dynamic changes during synthesis as well as operation of ASSBs. The understanding of these mechanisms will lead to optimized ASSBs with improved capacity retention, charging rates, and lifetime.