Electrochemical Activation Inducing Rocksalt-to-Spinel Transformation for Prolonged Service Life of LiMn₂O₄ Cathodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium manganese oxide (LiMn2O4) spinel is a promising cathode material for lithium-ion batteries due to its structural properties.
• However, LiMn2O4 cathodes suffer from structural degradation and capacity decay during cycling.

Purpose of the Study:

• To introduce an electrochemical activation strategy to restore the capacity of degraded LiMn2O4 cathodes.
• To enhance the cycle life and performance of LiMn2O4 based lithium-ion batteries.

Main Methods:

• Galvano-potentiostatic charging operation for electrochemical activation.
• Electron microscopy for structural analysis.
• Density functional theory simulations for mechanistic understanding.

Main Results:

• Extended cycle life of LiMn2O4 cathode from 1500 to 14,000 cycles at 5C rate.
• Increased total discharge energy by ten times.
• Enhanced Li+ diffusion coefficient by 37.2%.

Conclusions:

• Electrochemical activation effectively restores capacity and improves kinetics by transforming inactive surface layers back into active spinel.
• The strategy is viable in pouch cell configurations with Li metal anodes, showing broad applicability.