Synthesis and performance of spherical LiNixCoyMn1-x-yO2 regenerated from nickel and cobalt scraps

To reduce the cost of the complex separation process of nickel, cobalt or manganese from the leaching liquid, a high value-adding process for the direct synthesis of LiNi0.8Co0.1Mn0.1O2,LiNi0.33Co0.2Mn0.3O2 and LiNi0.33Co0.33Mn0.33O2 as active cathode materials by the hydroxide co-precipitation method is developed in this paper. The structure, morphology and composition of the regenerated LiNixCoyMn1-x-yO2 cathode materials are determined with X-ray diffraction (XRD), scanning electrori microscopy (SEM), X-ray photoelettron spectroscopy (XPS), inductively coupled plasma atomic emission spectrometry (ICP-AES) and energy dispersive X-ray spectroscopy system (EDXS), respectively. The results show that the regenerated cathode materials have a well-defined layered structure and retain the characteristics of their corresponding hydroxide precursors with a spherical morphology and a particle size in the range from 9 to 12 pm in diameter. Electrochemical tests show that the regenerated cathode materials have good electrochemical performances. The initial discharge capacities (0.1C, 2.7-4.3 V) of the regenerated LiNixCoyMn1-x-yO2 are 197.7 mAh g(-1), 174.3 mAh g(-1) and 168.3 mAh g(-1) for x = 0.8, 0.5 and 0.33, respectively. The discharge capacities of all materials decrease with increasing discharging current densities and the capacity retention ratios of LiNi0.8Co0.1Mn0.1O2, LiNi0.5Co0.2Mn0.3O2 and LiNi0.33Co0.33Mn0.33O2 are 86.3%, 95% and 96% respectively after 50 cycles. Overall, the results show that the performances of regenerated LiNixCoyMn1-x-yO2 are similar to those of the materials prepared from mixed solution of virgin nickel, cobalt and manganese chemicals. (C) 2015 Elsevier B.V. All rights reserved.