Cathode active material and lithium secondary battery containing the same

High-nickel cathode active material with a pre-formed spinel layer at the primary particle terminals via tungsten doping

This technology secures structural stability in high-nickel cathode active materials by doping tungsten (W) at the surface terminals of primary particles to pre-form a spinel structure that coexists with the layered structure.

High-nickel cathode active materials have historically suffered from structural instability during charge-discharge cycles, leading to the formation of irregular spinel structures on the surface. This process causes micro-cracks, which limit cycle life and thermal stability.

This technology forms a 5–50nm thick spinel region at the terminals of primary particles on the secondary particle surface before the initial charge. W-doping increases the lattice parameter 'a' to facilitate lithium-ion diffusion, while the pre-established spinel structure prevents disordered phase transitions during cycling. Applicable to ultra-high-nickel cathodes (Ni 90mol%+) and long-life cells for medium-to-large battery packs, it serves as a foundation for cathode design targeting over 80% capacity retention after 500 cycles.

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Key Features:

• First primary particles located on the surface of the secondary particle, having a spinel structure in the first region at the terminals of the layered structure
• Layered primary particles composed of lithium, nickel, cobalt, manganese, and tungsten as a doping element
• A first region where the area expands and the lattice parameter 'a' increases as the doping element content increases
• A first region with a spinel structure formed from the outermost surface of the first primary particle to a depth of 5nm to 50nm

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