Core-Shell Positive Electrode Active Material for Battery Stability

The patent applies local quality by creating a core-shell structure where the central region contains high-nickel content (LiNi0.8Co0.1Mn0.1O2) for high capacity, while the peripheral region contains nickel-poor composite oxide for stability. This spatial differentiation of composition allows each region to perform its specialized function: the core provides high power density while the shell provides structural stability and safety.

The patent employs composite materials by combining two distinct oxide phases: a high-nickel lithium nickel cobalt manganese oxide core and a nickel-poor lithium cobalt nickel manganese oxide shell. This composite structure integrates the advantages of both materials - the high capacity of nickel-rich compounds and the stability of nickel-poor compounds - while mitigating their individual disadvantages.

The patent reduces manufacturing cost through local quality by concentrating expensive nickel in only the core region (approximately 70-80% of particle volume) rather than throughout the entire particle. The shell region uses nickel-poor composition, significantly reducing overall nickel content while maintaining high capacity through the high-nickel core's contribution to total capacity.

The patent uses a coprecipitation method to create a precursor hydroxide that replicates the desired core-shell composition and structure. This copying approach allows complex multi-element distribution to be achieved through a relatively simple one-step precipitation process followed by calcination, avoiding more expensive multi-step manufacturing procedures.

The patent addresses deterioration by applying local quality through the core-shell structure where the nickel-poor shell specifically protects the high-nickel core from degradation mechanisms such as surface reconstruction, electrolyte decomposition, and transition metal dissolution. This localized protection strategy preserves charge-discharge characteristics over extended cycling while maintaining the high-speed performance enabled by the nickel-rich core.

The patent implements beforehand cushioning by pre-forming a protective shell layer around the high-nickel core before the material undergoes cycling stress. This pre-existing protective structure cushions the core against mechanical and chemical degradation that would otherwise occur during charge-discharge cycles, thereby extending cycle life while preserving high-rate performance.