Exploring Cathode and Solid Electrolyte Materials for All-solid-state Battery Applications

本项目主要研究应用于锂离子全固态电池（ASSB）的新型正极和固体电解质（SE）材料。在这里，活性材料（AM）、碳（以增加导电性）和SE的粉末被烧结在一起作为阴极球团，然后在其顶部覆盖一层SE，最后附着在阳极上；锂金属。assb克服了安全问题（例如有机电解质的易燃性），并产生了在略高温度下也能工作的坚固且惰性的电池。迄今为止，对于锂离子在SE中的输运机制、合成和操作过程中形成的相和界面、以及起始材料的粒度如何影响致密/烧结和电化学性能，所知甚少。我们将使用经典的固态合成路线来生产新的AM（例如LFP和更高电压的阴极，例如NMC和LMP）和SE（例如LSPO， LLZO和LPS）材料并控制其粒径。火花等离子烧结（SPS）是一种新型的加工技术，将用于生产AM/SE阴极复合材料的致密球团。粉末XRD将用于确定原始材料和SPS制备的复合材料的相纯度和粒度。粉末和颗粒将用于电化学测试。固态核磁共振将用于在局部原子尺度上深入了解不同的化学环境/相，获得活化能并了解潜在的离子扩散机制。下一步，原位核磁共振将用于实时研究结构变化。环境影响评价系统将用于推导电导率；这些数据将与核磁共振研究相结合。另一种重要的方法将是对颗粒/复合材料进行电子显微镜检查，对比差异将提供颗粒（大小）分布和存在的相的信息，而EDX将允许对元素组成进行量化。

This project is focused on the investigation of new cathode and solid electrolyte (SE) materials for applications in Li-ion all-solid-state batteries (ASSB). Here, powders of the active material (AM), carbon (to increase the electrical conductivity) and SE are sintered together as a cathode pellet, which is then topped by a layer of SE and, finally, attached to an anode; e.g. Li metal. ASSBs overcome safety issues (e.g. flammability of organic electrolytes) and result in robust and inert batteries that function at slightly elevated temperatures.To date, only little is known on the detailed mechanisms of Li-ion transport in SE, the phases and interfaces forming during synthesis and operation, and how particle sizes of the starting materials influence both, the densification/sintering and electrochemical performance. We will use classical solid-state synthesis routes to produce new AM (e.g. LFP and higher voltage cathodes such as NMC and LMP) and SE (e.g. LSPO, LLZO, and LPS) materials and control their particle sizes. Spark Plasma Sintering (SPS), a novel processing technique, will then be applied to produce dense pellets of AM/SE cathode composites. Powder XRD will be used to determine phase purity and particle sizes of both the pristine materials as well as the composites prepared by SPS. The powders and pellets will be used for electrochemical testing. Solid-state NMR will be utilised to gain insights into different chemical environments/phases on a local atomic scale, derive activation energies and learn about the underlying ion diffusion mechanism. In a next step, in situ NMR will be applied to study structural changes in real-time. EIS will be used to derive conductivities; the data will be combined with the NMR studies. Another crucial method will be electron microscopy on pellets/composites Contrast differences will give information on particle (size) distributions and phases present, while EDX will allow a quantification of the elemental composition.