Surface Reconstruction Enhanced Li-Rich Cathode Materials for Durable Lithium-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Surface element distribution in lithium-rich cathode materials critically impacts electrochemical performance.
• Manganese (Mn) enrichment on the surface leads to irreversible phase transitions and dissolution, degrading performance.

Purpose of the Study:

• To design and prepare a lithium-rich cathode material with surface-enriched nickel (Ni) and cobalt (Co).
• To investigate how Ni and Co surface enrichment mitigates Mn dissolution and improves structural stability.

Main Methods:

• Utilizing a molten salt-assisted sintering method for material preparation.
• Characterizing the surface structure and electrochemical performance of the modified cathode material.

Main Results:

• Surface enrichment of Ni and Co effectively reduced Mn dissolution.
• The Ni- and Co-rich surface promoted a stable layered-to-rock salt phase transition, enhancing crystal structure stability.
• Achieved 189.8 mAh g^-1 discharge-specific capacity after 500 cycles at 1 C, with 88.9% capacity retention (a 42.1% improvement).

Conclusions:

• Molten salt treatment with Ni and Co surface enrichment is a viable strategy to improve the stability and cycling performance of lithium-rich cathode materials.
• This approach offers promising avenues for the commercial application of advanced battery materials.