Thermochemically driven crystal phase transfer via chlorination roasting toward the selective extraction of lithium from spent LiNi1/3Co1/3Mn1/3O2

Abstract The selective extraction of lithium from spent lithium-ion batteries (LIBs) is significant for combating potential lithium deficiencies and for providing environmental protection by enabling highly selective Li extraction through a short path. Herein, we demonstrate a thermochemically driven process for spent LiNi1/3Co1/3Mn1/3O2 (NCM) batteries by systematically understanding the conversion mechanisms and controlling the chlorination behavior during chlorinated roasting. First, software simulations based on thermochemical differences are introduced to select customized chloride salts for the thermal treatment of spent NCM materials. The thermal behavior characterization studies are combined with thermochemical calculations, showing that CaCl2 and its hydrates energetically favor the preferential destruction of the layered structure of lithium oxides and transform them into water-soluble chloride compounds. Based on this unique mechanism, the established lithium extraction system achieves outstanding selectivity and realizes the target of an acid-free method, greatly reducing its negative environmental impact. This work may shed new light on the mechanism of chlorination roasting for selective extraction and provide resources to develop promising technology for the green and selective extraction of lithium from spent NCM batteries.