High-Ni Cathode Material Gradient Structure for Lower Resistance

The patent applies local quality by creating a concentration gradient structure where nickel content varies spatially within the secondary particle. The surface region has higher nickel content (0.8-0.95 mole ratio) to provide high discharge capacity, while the inner region has lower nickel content (0.5-0.7 mole ratio) to maintain low resistance and structural stability. This spatial variation in composition allows simultaneous optimization of both capacity and reliability.

The patent creates a composite structure within the lithium composite oxide secondary particle, combining regions with different nickel concentrations. This internal composite structure integrates the advantages of high-nickel materials (high capacity) and low-nickel materials (low resistance, high stability) into a single functional material system.

The patent segments the secondary particle into distinct regions with different nickel concentrations - a surface region and an inner region. This segmentation allows each region to be optimized independently for its specific function while simplifying the overall synthesis process compared to attempting to create uniform high-nickel LiNiO2 material throughout.

The patent changes the nickel concentration parameter spatially within the secondary particle, creating a gradient from the surface to the interior. This parameter variation allows the material to achieve high energy density without requiring the synthesis of difficult-to-manufacture uniform LiNiO2, as the average nickel content can be controlled while maintaining local high-nickel regions.