Recovery of Li₂CO₃ from Spent LiFePO₄ by Using a Novel Impurity Elimination Process

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Large-scale lithium iron phosphate (LFP) battery implementation necessitates efficient recycling due to resource depletion and waste accumulation.
• Recovering critical materials like lithium carbonate (Li2CO3) from spent LFP batteries is essential for supply chain security and carbon neutrality.

Purpose of the Study:

• To develop and validate an optimized hydrometallurgical process for high-purity lithium carbonate (Li2CO3) recovery from spent LiFePO4 batteries.
• To investigate impurity removal strategies crucial for achieving battery-grade Li2CO3.
• To confirm the electrochemical performance of recycled Li2CO3 in new LFP battery synthesis.

Main Methods:

• Investigated impurity removal from Li+-containing liquids using strong and weak alkalis under controlled pH conditions.
• Developed a strategy employing an alkali mixture for efficient impurity elimination.
• Concentrated the purified Li+-solution and precipitated Li2CO3 by adding sodium carbonate.

Main Results:

• Achieved high-purity battery-grade lithium carbonate (99.51%) through the developed alkali mixture strategy.
• Synthesized LiFePO4 using recovered Li2CO3, demonstrating comparable capacity and cycle stability to commercial products.
• Validated the electrochemical activity and suitability of the recycled materials for battery applications.

Conclusions:

• The proposed hydrometallurgical method effectively removes impurities, yielding high-purity Li2CO3 suitable for battery manufacturing.
• Recycled Li2CO3 maintains excellent electrochemical performance, supporting a circular economy for LFP batteries.
• This process contributes to sustainable battery material sourcing and reduces reliance on primary lithium resources.