Co-precipitation synthesis of precursor with lactic acid acting as chelating agent and the electrochemical properties of LiNi0.5Co0.2Mn0.3O2 cathode materials for lithium-ion battery

摘要

Hydroxide precursor Ni0.5Co0.2Mn0.3(OH)(2) was successfully prepared by co-precipitation using lactic acid as the environment-friendly chelating agent. And the thermodynamics model of hydroxide co-precipitation was proposed. The influence of chelating agent ion concentration on the structure and morphology of the precursors was discussed. The LiNi0.5Co0.2Mn0.3O2 cathode materials were obtained by sintering the mixture of as-prepared Ni0.5Co0.2Mn0.3(OH)(2) precursor and Li2CO3. The structural, morphological, and electrochemical performances of LiNi0.5Co0.2Mn0.3O2 cathode materials were investigated by using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and Land battery tester. The results showed that the quasi-spherical LiNi0.5Co0.2Mn0.3O2 with the size of about 5 mu m exhibited the excellent electrochemical performance when its Ni0.5Co0.2Mn0.3(OH)(2) precursor was synthesized at the molar ratio of 1:1 between lactate ion and transition metal ion. The initial discharge capacity was 194.2 mAh g(-1) at 0.1 C, and the discharge capacities of 108.6 and 95.7 mAh g(-1) were obtained at 3 and 5 C, respectively. In addition, the capacity retention rate was 93.3% after 100 cycles at 0.2 C.