Expandable Fast Li-Ion Diffusion Network of Li-Rich Mn-Based Oxides via Single-Layer LiCo(Ni)O₂ Segregation

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Li-rich Mn-based cathode materials offer high specific capacity (>250 mAh g^-1) for next-generation lithium-ion batteries.
• These materials suffer from poor rate and cycling performance, limiting their practical application.
• Anion redox processes in these materials contribute to capacity but can lead to structural instability.

Purpose of the Study:

• To synthesize a Li-rich cathode material with an enhanced fast Li-ion diffusion network.
• To improve the rate capability and cycling stability of Li-rich cathode materials.
• To investigate the role of structural modifications in enhancing electrochemical performance.

Main Methods:

• Synthesis of a Li-rich cathode material incorporating a single layer of LiCo(Ni)O₂.
• Electrochemical characterization, including rate capability tests and long-term cycling at 2.1-4.6 V.
• Analysis of structural stability during anion redox processes.

Main Results:

• The synthesized material achieved a capacity of 212 mAh g^-1 at 5 C, demonstrating enhanced rate performance.
• The single-layer LiCo(Ni)O₂ effectively isolated Li₂MnO₃ domains, improving structural stability.
• Capacity retention reached 80% after 400 cycles with minimal voltage decay (0.74 mV/cycle).

Conclusions:

• Incorporating an expanded fast Li-ion diffusion network significantly boosts the rate capability of Li-rich cathodes.
• Structural stabilization via LiCo(Ni)O₂ integration enhances electrochemical stability and cycle life.
• This approach offers a promising strategy for developing high-performance layered oxide cathode materials.