Surface BO₃ Configuration in Li-Rich Cathode Materials Enabling Highly-Stable Anionic Redox Reactions

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Li-rich Mn-based layered oxides (LRMOs) offer high capacity for next-generation lithium batteries.
• LRMOs suffer from lattice-oxygen release and degradation, causing poor initial efficiency and cycling stability.

Purpose of the Study:

• To enhance the stability and performance of LRMOs by introducing a B-heterogeneous coordination structure.
• To suppress oxygen loss and improve cycling stability in high-energy-density lithium batteries.

Main Methods:

• Incorporation of a boron (B) heterogeneous coordination structure into LRMOs.
• Formation of a ≈4 nm surface layer enriched in BO3 units, with BO4 units in the bulk.
• Analysis of bonding interactions between B-O and transition metal-O bonds.

Main Results:

• The modified LRMOs achieved a high reversible capacity of ~300 mAh g⁻¹ at 0.1C.
• An enhanced initial Coulombic efficiency of 93.5% was observed.
• Excellent capacity retention of 85.8% after 300 cycles at 1C was demonstrated.

Conclusions:

• The surface BO3 structure effectively anchors lattice oxygen, suppressing irreversible oxygen loss.
• The heterogeneous coordination reconciles oxygen-redox activity with long-term stability in LRMOs.
• This approach provides a new strategy for developing stable, high-energy-density lithium batteries.