Nickel-Rich Cathode Powder Structure to Limit Cracking and Side Reactions

The patent divides the particle structure into multiple primary particles aggregated to form secondary particles, where each primary particle maintains structural integrity while the secondary particle structure provides increased capacity. The segmentation allows lithium ions to penetrate through multiple interfaces, improving capacity while the bonded structure prevents excessive breakage during rolling.

The patent uses composite NCM-based lithium composite transition metal oxides containing multiple transition metals (Ni, Co, Mn) to achieve both high capacity and improved structural stability. The composite material structure combines the high capacity of nickel-rich phases with the stability of cobalt and manganese phases, reducing cracking during charging/discharging while maintaining secondary particle morphology for capacity enhancement.

The secondary particle structure segments the total surface area into multiple smaller primary particle surfaces. While the total contact area with electrolyte is larger than single particles, the segmented structure reduces the harmful effects by distributing reactions across multiple interfaces and creating internal pathways that limit electrolyte penetration depth, thereby managing side reactions while maintaining high capacity.

The patent employs a coating layer as an intermediary substance between the NCM-based lithium composite transition metal oxide particles and the electrolyte. This coating layer acts as a protective barrier that reduces direct contact between the electrolyte and the active material surface, minimizing side reactions such as electrolyte decomposition and transition metal ion dissolution while allowing lithium ion transport.

The patent segments the particle into multiple primary particles that are bonded to form secondary particles. This segmentation creates multiple internal interfaces within the secondary particle structure, providing additional pathways for lithium ion diffusion. The segmented architecture maintains the structural strength of individual primary particles while the network of interfaces enhances lithium mobility compared to dense single particles.

The patent transforms the particle structure from a single-dimension solid sphere to a multi-dimensional aggregated structure composed of multiple primary particles. This dimensional transformation creates internal porosity and interconnected pathways that enhance lithium ion diffusion routes, improving lithium mobility while maintaining the structural integrity benefits of the aggregated morphology.

The patent performs preliminary actions during the particle formation process by controlling precipitation and drying conditions to directly form the desired secondary particle morphology with bonded primary particles. This preliminary structuring eliminates the need for subsequent high-temperature firing to create single particles, reducing energy consumption and manufacturing complexity while achieving the required particle strength through the bonded aggregate structure.

The patent changes the processing parameters from high-temperature firing (which requires complex equipment and high energy input) to controlled precipitation and drying processes. By adjusting parameters such as pH, temperature, and drying rate during precursor formation, the patent achieves the desired particle morphology and strength without requiring extreme firing conditions, thereby simplifying the manufacturing process.