The layered Li-rich Li[Li0.2Mn0.54Ni0.13Co0.13]O2 cathode material is successfully synthesized via an optimized sol–gel method. With oxalic acid instead of citric acid as the chelating agent, the amount of chelating agent used in this experiment is only 36% of the traditional weight. Segmented sintering method is adopted to decrease the calcination temperature and reduce the calcination time. X-ray diffraction spectrometry (XRD) and scanning electron microscopy (SEM) are used to characterize the structure and micromorphology of the material. Meanwhile, charge–discharge test, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) are employed to explore its electrochemical performance. Our results demonstrate that Li[Li0.2Mn0.54Ni0.13Co0.13]O2 electrode delivers a high reversible capacity of 277.3mAhg−1 and keeps excellent capacity retention of 98.4% after 50 cycles when tested at a 0.1C rate within the potential range of 2.0–4.8V at room temperature.