Cathode Active Material for Sodium-Ion Batteries and Sodium-Ion Battery Comprising the Same

Highly Stable Cathode Material for Sodium-Ion Batteries Featuring a P2/O3 Composite Phase via Mg, Ti, and Zr Doping

This technology implements a composite crystal structure where P2 and O3 phases coexist by doping a Na-Ni-Mn-Fe-based layered cathode active material with Mg, Ti, and Zr, thereby mitigating lattice strain during charge/discharge cycles and improving ion mobility.

Conventional transition metal-based layered cathode materials (Na-Ni-Mn-Fe series) offer high discharge capacity but suffer from a rapid decline in capacity retention due to structural instability during repeated charge/discharge cycles.

By designing a cathode active material with a composition of Na a Ni b Mn c Fe d Mg e Ti f Zr g O h (where 0.70≤a≤0.80, etc.), this technology provides new design flexibility in the field of lithium secondary battery cathode materials.

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Key Features:

• Cathode active material for sodium-ion batteries featuring a composite crystal structure with coexisting P2 and O3 phases achieved through Mg, Ti, and Zr doping
• Layered cathode active material containing sodium, nickel, manganese, and iron, along with magnesium, titanium, and zirconium in a specific stoichiometric ratio
• Composite crystal structure that enhances sodium-ion mobility by expanding the c-axis lattice through Mg, Ti, and Zr doping
• Cathode active material designed to improve capacity retention by mitigating lattice strain during charge and discharge

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