Nickel-Rich Cathode Material With Cobalt Gradient and Surface Coating

The patent applies local quality by creating a gradient distribution of cobalt elements within the lithium-nickel composite oxide particle, where the cobalt content varies from the surface to the center. This gradient structure provides different local compositions optimized for specific functions: surface regions with higher cobalt content for stability and safety, and inner regions with lower cobalt content for high capacity, thereby resolving the contradiction between energy density and cycle performance

The patent uses composite materials by combining lithium-nickel composite oxide with cobalt elements distributed in a gradient manner within the particle structure. This composite approach allows the material to simultaneously exhibit high energy density characteristics from the nickel-rich core and improved cycle performance from the cobalt-modified regions, effectively addressing the reliability issue while maintaining high energy density

The gradient distribution of cobalt elements creates local quality variations where surface and near-surface regions have higher cobalt content to enhance safety characteristics such as thermal stability and structural integrity, while the core maintains high nickel content for energy density, thus resolving the safety contradiction

The cobalt elements are pre-distributed within the lithium-nickel composite oxide particle before battery operation through the controlled synthesis process. This preliminary action of incorporating cobalt in a gradient distribution ensures that safety-enhancing regions are already in place to prevent harmful reactions and maintain structural stability during battery cycling and thermal events