Leaching kinetics of de-lithium residue from spent ternary lithium-ion battery cathodic materials with starch as reductant

Starch was employed as a reductant for the recovery of Ni, Co, and Mn from ternary lithium-ion batteries (LIBs) cathodic materials de-lithium residue, and the leaching kinetics and mechanism were studied. The effects of stirring speed, leaching temperature, H2SO4 concentration, and starch dosage on leaching efficiencies of Ni, Co, and Mn from de-lithium residue were systematically investigated. Optimized conditions (1.5 mol/L H2SO4, 6 g/L starch, stirring speed of 500 r/min, 80 °C and 60 min) yielded leaching efficiencies of 98.07%, 96.52%, and 98.06 %, for Ni, Co, and Mn, respectively. Apparent activation energies, described by the chemically controlled unreacted shrinking core model, were 93.32, 102.84, and 95.68 kJ/mol, for Ni, Co, and Mn, and their apparent reaction orders in H2SO4 were 0.9225, 1.0335, and 1.1285, respectively. Starch is abundant, affordable, and exceptionally alternative to conventional reductants for the recovery of valuable metals from spent ternary LIBs.