Resynthesis of NMC111 cathodic material from real waste lithium ion batteries

In this work, the role of the experimental conditions during the synthesis of LiNi1/3Mn1/3Co1/3O2 cathodic material (NMC) precursor was evaluated. Precursor synthesis was carried out starting from the electrodic powder obtained from the mechanical treatment of spent lithium ion batteries. Metals were extracted by acidreducing leaching of the electrodic powder with an extraction yield higher than 90%. Cobalt was the most concentrated metals followed by manganese and nickel. Iron, copper and aluminium, coming from battery cases and current collectors, were present as impurities in the leachate. Selective precipitation of the impurities was performed prior to precipitate the mixed hydroxide. Ni1/3Mn1/3Co1/3(OH)2 precipitations were carried out using two concentrations of NH4OH and under nitrogen or air atmosphere. The effect of these parameters was evaluated on the NMCs structure by XRD analysis and on the electrochemical performance by the galvanostatic cycling of the NMCs when assembled in half lithium cells. XRD analysis of the NMCs have showed the obtainment of the typical layered structure of LiNi1/3Mn1/3Co1/3O2 for any synthesized NMC and no other phases related to single oxides were found. The evaluation of the electrochemical performance has showed a significant role of the precipitation atmosphere and an improvement of the specific capacity was attained using the lowest concentration of NH4OH. Remarkably, specific capacity values of recovered NMCs were comparable to NMCs synthesized under the same experimental conditions but using synthetic reagents.