An environmentally friendly process for selective recovery of lithium and simultaneous synthesis of LiFe5O8 from spent LiFePO4 battery by mechanochemical

This study provides a green, economical, and effective approach for selective recovery of lithium from spent LFP battery by inducing electron transfer through mechanochemical activation, and the leaching solution was simultaneously converted to a magnetic functional material LiFe5O8. In the mechanochemical process, only ferric chloride was used as a grinding agent. Experimental results showed that more than 97 wt% of lithium in the cathode materials could be selectively recovered with a purity of 99.9% under optimal conditions (FeCl3:LiFePO4 mass ratio of 1.2:1, rotary speed of 600 rpm, and reaction time of 30 min). Mechanism analysis indicated the key point was that electrons were transferred to ferric chloride from LFP cathode material, and the LFP was oxidized to iron phosphate during mechanochemical activation, but the olivine structure of the cathode material remained unchanged. Therefore, lithium could be easily extracted from the olivine structure. In addition, the LiFe5O8 synthesized from spent LFP battery has good magnetic properties, in which the saturation magnetization (Ms) was 49.23 emu/g. Economic analysis indicated that the income from recycling one ton of spent LFP batteries was $4959.39. It is confident that this study developed a green and economic process for high-value-added recycling of spent LFP batteries.