Lithium-Metal Oxide Cathode Gradient and Ceramic Separator

The cathode active material is designed with a core-shell structure where the core region contains lithium transition metal oxide for high capacity, while the shell region contains lithium phosphate for thermal stability. This spatial differentiation of material composition allows the battery to simultaneously achieve high capacity from the core and thermal stability from the shell, resolving the contradiction between capacity and thermal stability.

The invention uses a composite cathode active material consisting of lithium transition metal oxide and lithium phosphate in a core-shell configuration. This composite structure combines the high capacity characteristics of lithium transition metal oxide with the thermal stability of lithium phosphate, enabling the battery to maintain both high performance and safety under thermal stress.

The lithium phosphate shell is预先 formed around the lithium transition metal oxide core to provide thermal cushioning before any short circuit or thermal runaway event occurs. This protective shell acts as a thermal barrier that absorbs and dissipates heat, preventing rapid temperature increase and ignition even when external impact causes internal short circuits, thus resolving the contradiction between energy density and ignition resistance.

The lithium phosphate shell serves as an intermediary protective layer between the high-energy lithium transition metal oxide core and the external environment. During thermal runaway or short circuit events, this intermediary shell moderates the heat transfer and prevents direct contact between reactive materials, thereby preventing ignition while maintaining the high energy density of the core material.

The core-shell structure creates a stable shell region containing lithium phosphate that prevents metal component desorption from the core during high-temperature storage. This localized protective composition maintains the overall cathode structure integrity and prevents degradation, thereby extending battery lifespan while preserving the high-capacity core material composition.

The composite cathode active material combines lithium transition metal oxide with lithium phosphate in a core-shell structure. The lithium phosphate component provides structural stability and prevents metal desorption during thermal aging, ensuring long-term compositional stability and extending battery lifespan without sacrificing the high capacity characteristics of the lithium transition metal oxide core.