Recycling of Lithium-Ion Batteries: Effect of Hydrogen Peroxide and a Dosing Method on the Leaching of LCO, NMC Oxides, and Industrial Black Mass

The effect of hydrogen peroxide on the leachability ofdifferentreference cathode active materials used in lithium-ion batteries (LCO,NMC 111, NMC 622, and NMC 811) was investigated using 2 M H2SO4. An innovative method was used to monitor the consumptionand residual concentration of hydrogen peroxide, which can help optimizeits addition and improve the economy and resource yield of the process.The reducing effect of hydrogen peroxide was compared using two methodsof adding it. Leaching with hydrogen peroxide significantly improvedthe dissolution and 100% yield was reached within 15 min for the NMCoxides (except NMC 811) and within 30 min for LCO. Co and Ni weremore easily leached from NMC 811 compared to other NMC oxides. Thedissolution of metals from LCO was in general slower. Cu and Al canalso act as reducing agents and their presence increased the leachingyield of the transition metals, especially Mn, and resulted in lessresidual hydrogen peroxide. The H2O2 additionmethod (all at once or charged at multiple occasions) did not influencethe maximum leachability (except for Mn/NMC 811) or the amount ofconsumed hydrogen peroxide, but the rate of dissolution was slowerwhen charging at multiple times. The optimal conditions determinedfor the reference NMC 111 cathode material [3% v/v H2O2 (59% w/w), S/L 1:20 g/mL, 2 M H2SO4, 50 & DEG;C] were applied for an industrial black mass sample (Li(1.09)Ni(0.31)Mn0(.39)Co(0.39)O(2)). The result was 100% yield for Li, Mn, and Ni, after 15min and 100% yield for Co after 60 min. Optimizedprocess decreases reagents consumption and carbonfootprint and increases the efficiency of the recycling process.