Stress-Mediated Lattice Reconstruction Regenerates Spent LiFePO₄ Cathodes.

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Energy

Background:

• Spent lithium-ion batteries (LIBs) pose a growing environmental challenge.
• Lithium iron phosphate (LFP) cathodes suffer performance decay due to lithium loss and structural defects.

Purpose of the Study:

• To investigate the fundamental cause of LFP cathode degradation.
• To develop an effective regeneration strategy for spent LFP batteries.

Main Methods:

• Identified stress-induced structural degradation as the root cause of LFP performance loss.
• Developed a stress-regulated electrochemical regeneration technique using an applied electric field.
• Applied magnesium and aluminum co-doping to enhance structural robustness.

Main Results:

• Reduced Li-Fe anti-site defects from 3.24% to 1.05%.
• Released accumulated lattice micro-strain, improving Li+ transport.
• Regenerated LFP achieved 94% capacity retention after 500 cycles.
• Life-cycle assessment indicated economic and environmental benefits.

Conclusions:

• Performance decay in LFP is primarily due to stress-induced structural degradation.
• The developed regeneration strategy effectively repairs LFP cathodes.
• Co-doping enhances long-term structural stability and electrochemical performance.