Sustainable recycling of spent ternary lithium-ion batteries via an environmentally friendly process: Selective recovery of lithium and non-hazardous upcycling of residue

As more spent ternary Co-poor lithium-ion batteries (LIBs) appear, traditional recycling processes could be challenged because of the reduced revenues caused by complex separation-purification processes. In this study, a cost-effective and environmentally friendly hydrometallurgical process assisted by the versatile oxalic acid is proposed for recycling spent ternary Co-poor LIBs. In this process, lithium is selectively leached without reductants because of the differences in oxalate solubility. Its selectivity is up to 95.0 %, which is 2.5 and 9.5 times that of formic acid and phosphoric acid/hydrogen peroxide selective leaching systems, respectively. The obtained lixivium can be reused in the leaching step to realize the enrichment of Li+, thereby reducing the discharge of wastewater and energy consumption required to recover Li+ in the form of Li2CO3. Additionally, the generated residue is non-hazardously converted into a porous functional material, whose performance in environmental treatment (i.e., emerging contaminant removal) and energy storage (i.e., supercapacitors) is superior to that of previously reported multifunctional materials. More importantly, this simplified process exhibits attractive profits (approximately $2,161/t) and is applicable to recycling multiple spent ternary Co-poor LIBs (e.g., NCM523 and NCM811). This study provides a promising route to sustainably recycle spent ternary Co-poor LIBs, probably contributing to developing spent ternary LIBs resource recycling process conformed to the goal of "carbon neutrality."