Synthesis and characterization of Li1.05Co0.3Ni0.35Mn0.3M0.05O2 (M=Ge,Sn)cathode materials for lithium ion battery

In order to improve the electrochemical performance and thermal stability of Li_1.05Co_1/3Ni_1/3Mn_1/3O₂ materials, Li_1.05Co_0.3 Ni_0.35Mn_0.3M_0.05O₂(M=Ge,Sn) cathode materials were synthesized via co-precipitation method. The structure, electrochemical performance and thermal stability were characterized by X-ray diffraction(XRD), charge/discharge cycling, cyclic voltammetry(CV), electrochemical impedance spectroscopy(EIS) and differential scanning calorimetry(DSC). ESEM showed that Sn-doped and Gedoped slightly increased the size of grains. XRD and CV showed that Sn-doped and Ge-doped powders were homogeneous and had the better layered structure than the bare one. Sn-doped and Ge-doped improved high rate discharge capacity and cycle-life performance. The reason of the better cycling performance of the doped one was the increasing of lithium-ion diffusion rate and charge transfer rate. Sn-doped and Ge-doped also improved the mateials thermal stability.