Synthesis and electrochemical study of Zr-doped Li[Li0.2Mn0.54Ni0.13Co0.13]O2 as cathode material for Li-ion battery

Li[Li0.2Mn0.54Ni0.13Co0.13]O2 materials doped with different Zr contents are studied using X-ray diffractometry (XRD), energy dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), charge–discharge measurements, AC impedance spectroscopy as well as cyclic voltammetry. These results demonstrate that the element Zr is distributed uniformly in these materials. With the increase of Zr content, the lattice parameters a, c and lattice volume V become larger. The discharge cycling curves of cells show that Zr doping enhances cycle life compared with the undoped one. The sample with x=0.01 shows the highest capacity and best cycling performance, especially at high current density. The Li[Li0.2Mn0.54−x/3Ni0.13−x/3Co0.13−x/3Zrx]O2 (x=0.01) delivers a capacity of 133.6 mA h g−1 (after 100 cycles) at the current density of 250 mA g−1, corresponding to the capacity retention of 83.8%. The favorable performance of the doped samples could be attributed to its enhanced structural stability and Li+ mobility.