In Situ Formed Core-Shell LiZnMn_2-O₄@ZnMn₂O₄ as Cathode for Li-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Lithium manganese oxide (LiMn₂O₄) is a promising cathode material for lithium-ion batteries (LIBs).
• Improving its electrochemical performance, particularly capacity and cycling stability, remains a key challenge.
• Elemental doping and surface modification are established strategies to enhance LiMn₂O₄.

Purpose of the Study:

• To synthesize and characterize in situ formed core-shell LiZnMn_2-O₄@ZnMn₂O₄ cathode materials.
• To investigate the correlation between microstructure and electrochemical performance in Zn-doped LiMn₂O₄.
• To optimize Zn-doping content for superior LIB performance.

Main Methods:

• Synthesis of Zn-doped LiMn₂O₄ with varying doping concentrations.
• Microstructural analysis using spherical aberration-corrected scanning transmission microscopy (Cs-STEM).
• Electrochemical performance testing, including capacity retention and cycling stability at 5 C.

Main Results:

• Successful formation of a LiZnMn_2-O₄@ZnMn₂O₄ core-shell structure.
• Zn²⁺ ions were observed to dope the spinel bulk and form a surface shell.
• The optimized sample (LiZn_0.02Mn_1.98O₄) exhibited 95.8% capacity retention after 700 cycles.
• Initial capacity of the optimized sample was 80 mAh g^-1.

Conclusions:

• The in situ formed core-shell structure enhances structural stabilization of LiMn₂O₄ cathodes.
• Zn-doping offers an effective strategy for developing high-performance LIBs.
• Understanding the microstructure-performance interplay is crucial for designing advanced spinel cathodes.