Synergistic Cu/Y co-doping stabilizes anionic redox and crystal structure in P2-type layered oxide cathode for...

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• P2-type layered oxide cathodes offer high capacity via anionic redox reactions.
• Challenges include oxygen loss, phase transitions, and Jahn-Teller distortion, limiting practical use.

Purpose of the Study:

• To develop a synergistic Cu/Y co-doping strategy for stabilizing P2-layered oxide cathodes.
• To improve electrochemical performance by addressing structural and redox limitations.

Main Methods:

• Co-doping with Cu2+ and Y3+ based on functional-spatial complementarity.
• Synthesis and characterization of Na0.67Cu0.2Fe0.26Mn0.53Y0.01O2 (NCFMY-2).
• Electrochemical testing (capacity, cycling, rate capability) and theoretical investigations.

Main Results:

• Optimized NCFMY-2 achieved 175.78 mAh g-1 reversible capacity.
• Demonstrated excellent cycling stability (80.24% retention after 100 cycles) and rate capability (126.62 mAh g-1 at 2C).
• Cu/Y co-doping enhanced Mn oxidation state, reinforced the framework, and improved Na-O bonding, boosting anionic redox reversibility and suppressing phase transitions.

Conclusions:

• Synergistic Cu/Y co-doping effectively enhances structural stability and electrochemical performance of P2-layered oxide cathodes.
• This approach offers a generalizable design principle for high-performance, stable layered oxide cathode materials.