A stable lithium-rich surface structure for lithium-rich layered cathode materials.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Increasing demand for higher energy density in lithium-ion batteries.
• Li-rich layered oxides offer high specific capacities but suffer from cation mixing and capacity fade.
• Cation mixing in transition metal layers leads to phase transitions and reduced performance.

Purpose of the Study:

• To develop a surface modification strategy for Li-rich layered oxides to enhance cycling stability.
• To mitigate phase transitions and capacity loss caused by cation mixing.
• To improve the overall performance of lithium-ion battery electrodes.

Main Methods:

• Fabrication of Li-rich layered oxide with a regularly arranged nickel surface structure.
• Characterization of the surface structure and its impact on the bulk framework.
• Electrochemical testing to evaluate capacity, cycling stability, and retention.

Main Results:

• A stable Li-rich layered surface structure with regularly arranged nickel was achieved.
• The surface modification effectively mitigated unwanted phase transitions during cycling.
• Achieved a reversible capacity of 218.3 mAh g^-1 at 1C with 94.1% retention after 100 cycles.
• Demonstrated improved cycling stability compared to unmodified electrodes.

Conclusions:

• The designed surface structure enhances the structural integrity of Li-rich layered oxides.
• This surface modification strategy effectively suppresses capacity fade and improves battery performance.
• The approach is applicable to various battery electrodes prone to surface degradation.