This study developes a hydrothermal synthesis method tailored to lowering reaction temperatures and reducing carbon emissions. Lithium iron phosphate is synthesized through an innovative, environmentally hydrothermal synthesis technology. This approach employs a closed-system reaction, resulting in the reduction of waste gas emission and the promotion of crystallization at low temperatures. This achievement can increase the capability of our country for the production of energy-efficient and eco-friendly lithium iron phosphate materials. In this investigation, acid leaching is applied for the recovery of waste lithium iron phosphate, while the low-temperature, environmentally friendly hydrothermal synthesis technology developed by this institution is harnessed for lithium iron phosphate regeneration. Crystal phase analysis confirms the production of a high-purity lithium iron phosphate in a single phase, with particle sizes observed to be less than 1 micron. Electrochemical tests reveal that the regenerated lithium iron phosphate exhibits superior stability and kinetic performance when compared to waste lithium iron phosphate. Following 50 charge and discharge cycles, the capacity remains at 93%, accompanied by a remarkable Coulombic efficiency of 97%. In contrast, waste lithium iron phosphate batteries retain only 83% of their capacity, with Coulombic efficiency decreasing to 77%. Regenerated lithium iron phosphate maintains capacities of 91 mAh/g and 55 mAh/g under high-rate currents of 2C and 5C, respectively, while waste lithium iron phosphate fails to demonstrate effective charge and discharge capabilities. Furthermore, through the modification process, the capacity of regenerated lithium iron phosphate is enhanced from 55 mAh/g to 75 mAh/g at a high rate of 5C.

Lithium iron phosphate, Hydrothermal method, Lithium iron phosphate battery recycling, Lithium-ion battery