Enabling Ultrahigh-Power-Density LiMn_0.6Fe_0.4PO₄ Cathodes via Kinetics Limitation Breakthrough and Jahn-Teller...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• High-power lithium manganese iron phosphate (LMFP) cathodes face challenges from slow lithium-ion diffusion and Jahn-Teller distortion.
• These issues limit the performance and lifespan of LMFP-based batteries.

Purpose of the Study:

• To develop a synergistic substitution strategy to improve Li-ion diffusion kinetics and mitigate Jahn-Teller distortion in LMFP cathodes.
• To design high-power, long-life manganese-based cathode materials.

Main Methods:

• Partial substitution of PO4 tetrahedra with planar BO3 groups to create 3D Li-ion diffusion networks.
• Doping transition metal sites with Nb5+ to widen diffusion channels and enhance structural stability.
• Characterization of microstructure and electrochemical performance of the optimized LMFP cathode.

Main Results:

• The optimized LMFP cathode exhibited an ultrahigh reversible capacity of 126 mAh g-1 at 10C, a 3.6-fold improvement over pristine LMFP.
• Jahn-Teller distortion in MnO6 octahedra was suppressed by 36% due to improved structural stability.
• The cathode retained 80.2% of its initial capacity after 2000 cycles at 3C in pouch-type full cells.

Conclusions:

• The synergistic substitution strategy effectively overcomes intrinsic Li+ diffusion limitations and enhances structural stability.
• This approach provides a viable paradigm for designing high-power, long-life manganese-based cathode materials for advanced batteries.