Mechanofusion-derived cathode composite microstructures with scalable mixed conducting matrix coatings for solid...

The successful implementation of solid state batteries not only requires the use of high-capacity anodes, but also high-performance composite cathodes. However, the production of solid state battery cathode composites with optimized microstructures remains a significant challenge, especially for large-scale fabrication. Here, we present a scalable high-intensity dry mixing process to create tailored functional coatings on single-crystalline LiNi_0.82Mn_0.07Co_0.11O₂ via mechanofusion. We investigate the coating of LiNi_0.82Mn_0.07Co_0.11O₂ with the malleable halide solid electrolyte Li₃InCl₆ under various process conditions, linking process parameters obtained from discrete element method simulations with experimentally accessible morphological properties to offer guidelines for further optimization. In this way nanometer-thin covering coatings as well as thick matrix coatings are successfully produced. Incorporating carbon black into the thick matrix coating results in well-performing mixed conducting matrices that can be used directly as composite cathodes without further treatment. The compositions investigated enable stable cycling with a specific capacity of up to q_comp = 100 mAh g^-1 (based on the total mass of the composite cathode) at a C-rate of 1 C (60 min). While higher carbon black content is observed to improve CAM utilization, excessive amounts are detrimental for cell kinetics and chemo-mechanics, emphasizing the importance of the cathode mixing process and composition on overall cell performance.