Minimizing Inter-Lattice Strain to Stabilize Li-Rich Cathode by Order-Disorder Control

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Li-rich Mn-based layered (LMR) cathodes are promising for next-generation Li-ion batteries (LIBs) due to low cost and high energy density.
• Their commercialization is hindered by asynchronous structural evolution during cycling, causing lattice strain and rapid capacity decay.
• Heterogeneous composite structures in LMR cathodes exacerbate these issues, leading to poor electrochemical stability.

Purpose of the Study:

• To design and demonstrate an order-disorder coherent Li-rich Mn-based layered cathode structure.
• To investigate the impact of this structure on electrochemical performance, including voltage stability and cycling life.
• To elucidate the mechanism by which the order-disorder structure mitigates lattice strain and degradation.

Main Methods:

• Synthesis of an order-disorder coherent LMR cathode material.
• Electrochemical characterization, including cycling tests and voltage retention measurements.
• Structural analysis to correlate structural evolution with electrochemical performance.

Main Results:

• The designed LMR cathode exhibited a higher average voltage (by 0.25 V) compared to conventional layered oxide counterparts.
• Negligible voltage decay (97.6% retention after 100 cycles) and enhanced cycling stability (98% capacity retention after 200 cycles) were achieved.
• The order-disorder structure promoted synchronous and homogeneous structural evolution, minimizing lattice strain and preventing degradation.

Conclusions:

• The order-disorder coherent structure design significantly improves the electrochemical stability of Li-rich Mn-based layered cathodes.
• This structural control strategy effectively minimizes lattice strain and prevents layer collapse at high voltages.
• The findings demonstrate a feasible approach for optimizing Li-rich cathode materials for sustainable energy storage applications.