Metal-doped cathode active material for sodium-ion batteries, method for manufacturing the same, and sodium-ion battery comprising the same

Layered Cathode Material for Sodium-Ion Batteries with Enhanced Structural Stability via Uniform Ball-Milled Dopant Dispersion

This technology improves battery performance by uniformly mixing and doping transition metal dopants, such as Ti and Zr, into nickel-cobalt-manganese-based cathode active materials for sodium-ion batteries, thereby strengthening crystal structure stability and suppressing structural collapse in high-voltage ranges.

Conventional cathode active materials for sodium-ion batteries are prone to phase transitions or structural collapse during charge and discharge cycles, which has limited their capacity and cycle life.

This technology utilizes a ball-milling process to evenly distribute dopant precursors, such as TiO2 and ZrO2, throughout the interior and surface of transition metal oxide precursor particles. Subsequent heat treatment yields a secondary particle-type cathode active material with improved particle strength and tap density. Applicable to sodium batteries for large-scale energy storage systems or low-cost electric two-wheelers that require reduced reliance on lithium, this technology expands the usable high-voltage charging range and increases energy storage per cell.

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Key Features:

• Cathode active material with a dopant TM molar ratio b in the range of 0.025 to 0.035 in the composition Na1+a[(NixCoyMn1-x-y)1-b(TM)b]O2-cAc
• O3 layered structure active material particles in the form of secondary particles formed by agglomerated primary particles, with TM uniformly distributed within the particles
• Step of obtaining composite particles by ball-milling transition metal oxide precursor particles with dopant precursor particles such as TiO2 or ZrO2
• Step of heat-treating the composite particles, in which the dopant precursor is uniformly distributed internally and on the surface, after ball-milling with a sodium-containing compound

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This invention was developed with support from the Ministry of Science and ICT for the development of core and commercialization technologies for interface-optimized, rod-shaped secondary battery materials.

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