Use of grape seed as reductant for leaching of cobalt from spent lithium-ion batteries

Abstract The grape seed was novelly used as reductant for leaching of spent LiCoO2 material, which is idea of “waste + waste → resources”. About 92% Co and 99% Li could be leached under the optimized conditions of grape seed 0.6 g/g, malic acid 1.5 mol/L, 180 min, 80 °C, and slurry density 20 g/L. The catechin, EC and EGCG contained in grape seed could be employed as efficient reductants during leaching. The leaching process is controlled by combination of surface chemical reaction and diffusion with apparent activation energy of 11.96 kJ/mol, which is related to the form of Co(OH)3.