A core-shell structured LiNi_0.5Mn_1.5O₄@LiCoO₂ cathode material with superior rate capability and cycling performance

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Spinel lithium nickel manganese oxide (LiNi$_{0.5}$Mn$_{1.5}$O$_{4}$) is a promising cathode material.
• Its electrochemical performance, particularly at high temperatures and rates, requires improvement.

Purpose of the Study:

• To synthesize and characterize a core-shell structured LiNi$_{0.5}$Mn$_{1.5}$O$_{4}$@LiCoO$_{2}$ cathode material.
• To evaluate the impact of LiCoO$_{2}$ coating on electrochemical properties.

Main Methods:

• Sol-gel and solid-state synthesis methods were employed.
• Electrochemical performance was assessed, including cycling stability and rate capability.

Main Results:

• The LiNi$_{0.5}$Mn$_{1.5}$O$_{4}$@LiCoO$_{2}$ material exhibited enhanced ionic conductivity and Li$^{+}$ interfacial diffusion.
• Optimal performance was achieved with 1% LiCoO$_{2}$ coating, showing a discharge capacity of 122 mA h g$^{-1}$ at 10C.
• Capacity retention after 100 cycles at elevated temperature was 96.17% for the coated material, compared to 74.93% for the bare material.

Conclusions:

• The core-shell structure of LiNi$_{0.5}$Mn$_{1.5}$O$_{4}$@LiCoO$_{2}$ significantly improves electrochemical cycling stability at elevated temperatures.
• The LiCoO$_{2}$ coating enhances rate capability and mitigates side reactions, making it suitable for high-performance batteries.