Closed-loop recycling of valuable metals from spent LiCoO2 batteries through phosphate-chemistry-based process

Abstract

The sustainable recycling of valuable metals from spent lithium-ion batteries (LIBs) has attracted an increasing attention. While the uncontrollable nature of reactants from traditional processes will result in increased process cost and environmental footprint. Herein, phosphate chemistry based was process proposed for the recovery of valuable metals from spent LIBs, in which H3PO4 was used as both leachant and precipitant for the selective leaching of Li and direct precipitating of transition metals (Me, Me = Ni, Co, Mn, Fe). In this work, Li will be converted into soluble phosphate (i.e. LiH2PO4) while transition metals tend to form insoluble phosphates of Me3(PO4)2 and MeHPO4 under the optimized conditions, indicating the possibility for priority extraction of Li and direct conversion of transition metals into products under controlled experimental condition. Then, LiH2PO4 can be further recovered as struvite (MgNH4PO4·6H2O, the upcycling of P, recovery rate > 99.97%) and Li2CO3 (purity > 99.99%). This phosphate-chemistry-based recycling process is a validated and promising candidate towards the closed-loop recycling of valuable metals from spent LIBs with minimized impacts on the environment.