Investigation of a Jet-Based Direct Mixing Process for Improved Structuring of Conductive Battery Hetero-Agglomerates

Abstract

A jet-based direct mixing process is used to effectively mix heterogeneous materials. In this work, its application in the structuring, coating and agglomeration of cathode materials for all-solid-state battery (ASSB) production is investigated, with the aim of increasing the homogeneity and conductivity of the composites and ultimately improving battery performance. In this process, different particle systems consisting of lithium iron phosphate (LFP), carbon black (CB) and sodium chloride (NaCl) are dispersed in the gas phase and brought together in a mixing zone as particle-laden aerosol jets. The cathode material’s structure is studied through scanning electron microscopy combined with a focussed ion beam (SEM–FIB). Electrical conductivity measurements of the resulting composites assess the degree of mixing and the changes in tortuosity, while a laser light diffractor and a cascade impactor analyse the particle size distribution (PSD). The jet-based process effectively produces hetero-agglomerates with the possibility of creating different composite structures by adjusting the process parameters. The mass concentration influences not only the structure, but also the PSD in the flow and the electrical conductivity of the composite. The results serve as a basis for future experiments with solid electrolytes to comprehensively evaluate the process and the resulting battery materials.