Lithium Composite Oxide Core-Shell Structure for Battery Capacity

The positive electrode active material is divided into a core secondary particle and a shell layer, creating a segmented structure. The core contains primary particles with large diameters (1 μm or more) that provide resistance to pulverization, while the shell provides additional reactive surface area that increases capacity per weight. This segmentation allows both large and small particle characteristics to coexist in one material system.

The shell is nested around the core secondary particle, forming a core-shell structure. The core contains primary particles with diameters of 1 μm or more for mechanical strength, while the nested shell layer contributes additional capacity without compromising the core's resistance to pulverization. This nested arrangement enables the inner core to provide structural stability while the outer shell enhances reactive surface area.

The material is segmented into a core region with large primary particles for mechanical strength and a shell region with higher surface area for increased capacity. This segmentation allows the system to simultaneously achieve both high capacity per weight and high resistance to pulverization by assigning different functional roles to different parts of the structure.

Different regions of the active material have different local qualities: the core region has large primary particles optimized for mechanical strength and resistance to pulverization, while the shell region has a structure optimized for high surface area and reactive capacity. This local differentiation allows each region to excel at its specific function without compromising the other.