Single-Crystalline Cathode Synthesis via Eutectic Li-Salt Assisted Particle Deagglomeration

The growing demand for energy storage in automotive and other applications requires advanced lithium-ion batteries (LIBs) that offer higher energy density, longer cycle life, and improved safety. Cost reduction is crucial, requiring scalable synthesis methods. Current state-of-the-art cathodes, including Ni-rich and emerging Li-/Mn-rich layered oxides, typically have polycrystalline structures composed of fine-grained primary particles (100-200 nm) and assembled secondary particles (~10 μm). This microstructure is designed to increase the cycle life and volumetric energy density. However, these polycrystalline cathodes are prone to intergranular cracking during electrode calendering and battery cycling, leading to electronic isolation of active materials and increased side reactions that degrade electrochemical performance.
In this study, we present a planetary centrifugal deagglomeration technique for the scalable production of single-crystalline cathodes from co-precipitation precursors. During the dry mixing of precursors in a planetary centrifugal mixer, LiOH-LiNO₃ salts, composed near their eutectic point, can in situ melt due to inter-particle friction. This process allows for the reactive wetting, corrosion, and separation of grain boundaries in the polycrystalline precursors. This technique effectively deagglomerates the precursors, repacks the crystals, and homogenizes lithium-salt distribution, promoting the formation of coarse single-crystalline cathodes with improved electrochemical performance. Notably, this method enables the synthesis of high-performance single-crystalline cathodes with flexible compositions while minimizing resource input, energy consumption, and environmental impact due to the absence of excess chemicals.