Spatially Decoupled Redox Activities Enable High Capacity and Fast Kinetics in Co-Free Li-Rich Cathodes.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Cobalt-free lithium-rich layered oxides (Co-free LLOs) offer high capacity and cost-effectiveness for advanced lithium-ion batteries.
• Challenges include sluggish kinetics and complex redox regulation without cobalt, limiting performance.

Purpose of the Study:

• To address limitations in Co-free LLOs by implementing a spatially decoupled redox strategy.
• To enhance interfacial kinetics, bulk charge transport, and overall electrochemical performance.

Main Methods:

• Constructed a three-region functional architecture within Co-free LLO particles.
• Utilized fluorine substitutional regulation in the near-surface bulk region.
• Formed a localized spinel-like reconstructed region and a LiF-rich amorphous surface layer.

Main Results:

• Achieved a high reversible capacity of 310.11 mAh g⁻¹.
• Demonstrated an initial Coulombic efficiency of 87.7%.
• Exhibited superior rate capability due to optimized redox and ion transport.

Conclusions:

• The spatially decoupled redox strategy effectively overcomes intrinsic limitations of Co-free LLOs.
• The designed architecture provides distinct functionalities across multiple length scales.
• This approach offers a promising pathway for developing high-energy, cobalt-free cathodes.