LAUSR

The high-nickel ternary cathode material LiNixCoyMn1-x-yO2 has high theoretical capacity and can be filled the power density requirement of a foot-powered car. It is placed on high expectations. However, Li/Ni mixing occurred during charging and discharging, resulting in poor cycle performance of the material. In this paper, spherical Ni0.66Co0.20Mn0.14(OH)2 precursor as prepared by co-precipitation. Then, well-ordered spherical [Li(1-x)Kx](Ni0.66Co0.20Mn0.14)O2 was synthesized. The effect of k substitution on the crystal structure and electrochemical properties of Li(Ni0.66Co0.20Mn0.14)O2 systematically by using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), charge-discharge test, cyclic voltammetry (C–V) method, and electrochemical impedance spectroscopy (EIS) test. The initial discharge specific capacity of Li0.98K0.02Ni0.66Co0.20Mn0.14O2 is 202.0 mAh/g, 169.3 mAh/g, 138.8 mAh/g, and 117.8 mAh/g at 0.1 C, 0.2 C, 0.5 C, 1 C, respectively, which is higher than other materials. The [Li0.98K0.02](Ni0.66Co0.20Mn0.14)O2 shows the initial discharge capacity of 117.8 mAh/g with the capacity retention of 86.1% after 30 cycles at 1 C. It shows good cycle performance and rate performance. Results showed K substitution played an important role in the superior reversible capacity and good cycling performance of Li(Ni0.66Co0.20Mn0.14)O2.