High-value recovery of spent lithium iron phosphate black powder through pure Na2S2O8 leaching and furnace gas precipitating lithium

LiFePO 4 batteries have become a mainstream choice in the power battery market due to their high safety, long cycle life and low cost. Consequently, a large number of LiFePO 4 batteries will be retired as their lifespan ends, and disassembled to LiFePO 4 black powder. To address those issues such as low-value and environmental pollution during the traditional chemical recycling of spent LiFePO 4 black powder, a novel black powder recycling method is developed in this work. Firstly, this method achieves the direct recovery of P and Fe elements through Na 2 S 2 O 8 leaching, producing battery-grade FePO 4 without further purification. Then, this method achieves the low-cost recovery of Li element through furnace gas (containing CO 2 ) precipitating lithium, producing battery-grade Li 2 CO 3 , thereby combining environmental and economic benefits. Furthermore, the recycled Li 2 CO 3 and FePO 4 are used to directly re-synthesize LiFePO 4 . Comprehensive testing confirmed that the performance of the re-synthesized LiFePO 4 is comparable to that of commercial products. This method opens up a promising pathway for the sustainable and commercially viable recycling of spent LiFePO 4 black powder.