Activating Reversible Anionic Redox in Layered Oxide Cathodes for Highly Stable Sodium-Ion Batteries by Li/Nb...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Developing high-capacity, long-cycle cathode materials is crucial for sodium-ion batteries.
• Achieving reversible anionic redox activity and structural stability are key challenges.

Purpose of the Study:

• To address limitations in sodium-ion battery cathodes through Na-O-A configuration modulation.
• To enhance reversible anionic redox reactions and structural stability in P2-Na_0.67[Ni_xLi_yMn_1-x-y]O₂ materials.

Main Methods:

• Synthesized P2-Na_0.67Ni_0.23Mn_0.67Li_0.08Nb_0.02O₂ via Na-O-A configuration modulation.
• Investigated the material's electrochemical performance, including capacity and cycling stability.
• Analyzed the role of Na-O-Li/Nb configuration and Nb⁵⁺ species in enabling dual redox reactions and structural reinforcement.

Main Results:

• Achieved a reversible capacity of 158.4 mAh g^-1 at 0.1C.
• Demonstrated extraordinary cycling stability with 98.2% capacity retention after 500 cycles at 5C.
• Enabled dual cationic and anionic redox reactions (ARR) for enhanced capacity and suppressed oxygen release via Nb-O bonds.

Conclusions:

• The Na-O-A configuration modulation strategy successfully enhances cathode performance for sodium-ion batteries.
• The introduction of Na-O-Li/Nb configuration and Nb⁵⁺ is critical for improved capacity and stability.
• This approach offers a universal pathway for designing stable, high-energy cathodes for next-generation sodium-ion batteries.