Spent LiFePO₄ batteries valorization: integrated process for battery-grade FePO₄ production

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Spent LiFePO4 batteries pose significant recycling challenges.
• Efficient recovery of valuable elements like Lithium (Li), Iron (Fe), and Phosphorus (P) is crucial for sustainability.
• Existing methods often struggle with deep separation of elements and comprehensive resource utilization.

Purpose of the Study:

• To develop an integrated and efficient process for recycling spent LiFePO4 batteries.
• To achieve high recovery rates for Li, Fe, and P while ensuring deep separation of impurities.
• To demonstrate the industrial scalability of the proposed recycling method.

Main Methods:

• Alkaline pressure leaching for selective Li extraction and Fe-Al separation.
• Sulfuric acid leaching for P and Fe recovery, converting Ca to CaSO4·2H2O.
• Tributyl Phosphate (TBP) and Lix984 extraction for F and Cu removal.
• Hydrogen peroxide (H2O2) oxidation and crystallization for battery-grade FePO4 production.

Main Results:

• Selective Li extraction and deep Fe-Al separation achieved via alkaline pressure leaching.
• High extraction efficiencies: 99.2% P and 94.8% Fe using H2SO4 leaching.
• >99% removal of F and Cu, with concentrations <2 mg/L in raffinate.
• Production of battery-grade FePO4 through oxidation and crystallization.
• Overall recovery efficiencies: 97.88% Li, 92.91% Fe, and 95.49% P.

Conclusions:

• The integrated process enables comprehensive element recovery from spent LiFePO4 batteries.
• The method effectively separates impurities and produces high-purity battery materials.
• The process demonstrates strong potential for industrial-scale application in battery recycling.