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

P2/O3 Composite Phase Cathode Active Material for Sodium-Ion Batteries with Enhanced Structural Stability

This technology involves doping Mg, Ti, and Zr into a Na-Ni-Mn-Fe-based layered cathode active material to achieve a composite crystal structure where P2 and O3 phases coexist, thereby mitigating lattice deformation during charging and discharging and improving ion mobility.

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

Accordingly, this technology proposes the design of a cathode active material with a composition of Na a Ni b Mn c Fe d Mg e Ti f Zr gO h (e.g., 0.70≤a≤0.80). Specifically, through Mg, Ti, and Zr doping, it expands the c-axis lattice within the crystal structure, thereby enhancing sodium ion diffusion performance and suppressing irreversible phase transitions, which significantly contributes to securing electrochemical cycle life and reversibility.

‍

‍

Key Features:

• Provides a cathode active material for sodium-ion batteries, composed of the chemical formula NaaNibMncFedM1eM2fM3gOh.
• M1 is selected from one of Mg, Co, Al, and Y, and M2 is selected from one of Zn, Ti, Al, Cu, and Co.
• M3 is selected from one of Ti and Zr, and M1, M2, and M3 are composed of different elements.
• A sodium-ion battery comprising an electrolyte disposed between a cathode and an anode, wherein the cathode comprises a cathode active material having the composition of [Chemical Formula 1].

‍

This technology was developed with support from the National Research Foundation of Korea's research project on 'Development of 4V-class aqueous lithium-ion batteries through AI-based novel lithium salt discovery'.

‍