Research on the Restoration and Performance of Lithium Iron Phosphate Cathode Materials

Lithium iron phosphate batteries are extensively used across various fields because of their high safety and long cycle life. However, after prolonged use, repeated lithium ion insertion and extraction disrupt the original structure, leading to performance degradation. In the context of the strong demand for lithium resources, research into their restoration and performance enhancement holds significant importance. This study employs a combined solvent–thermal and high-temperature solid-state sintering method, in which ethanol is used as a reducing agent and lithium acetate is used as a lithium source to repair and regenerate waste lithium iron phosphate batteries. The effects of the addition of a lithium source, the solvothermal time, and the solvothermal temperature on the regenerated materials were investigated, and morphological, structural, and electrochemical performance tests were conducted. Additionally, the regenerated materials under optimized conditions were subjected to in-depth testing. The results indicate that, when the amount of added lithium source is 30 mg, the solvent–thermal time is 5 h, and the solvent–thermal temperature is 180°C, the recycled material exhibits optimal electrochemical performance, maintaining an efficiency of more than 90% after 100 cycles at 0.1 C, with an original specific capacity of approximately 155 mAh g⁻¹, outperforming recycled materials under other conditions.