Zn-doped LiNi1/3Co1/3Mn1/3O2 composite, Li(Ni1/3Co1/3Mn1/3)1–xZnxO2 (x = 0.02; 0.05; 0.08), is synthesized by the sol-gel method. The crystal structure, morphology, and electrochemical performance are investigated via X-ray diffraction (XRD), scanning electron microscope (SEM), cyclic voltammetry (CV), and constant current charge/discharge experiment. The result reveals that Zn-doping cathode material can reach the initial charge/discharge capacity of 188.8/162.9 mAh·g−1 for Li(Ni1/3Co1/3Mn1/3)0.98Zn0.02O2 and 179.0/154.1 mAh·g−1 for Li(Ni1/3Co1/3Mn1/3)0.95Zn0.05O2 with the high voltage of 4.4 V at 0.1 C. Furthermore, the capacity retention of Li(Ni1/3Co1/3Mn1/3)0.98Zn0.02O2 is 95.1% at 0.5 C after 50 cycles at room temperature. The improved electrochemical properties of Zn-doped LiNi1/3Co1/3Mn1/3O2 are attributed to reduced electrode polarization, enhanced capacity reversibility, and excellent cyclic performance. [ABSTRACT FROM AUTHOR]