In this study, highly dispersive spherical Li-rich solid solution (Li1.2Mn0.54Ni0.13Co0.13O2) particles are successfully synthesized by a co-precipitation method. Then these particles are treated with aluminum nitrates ethanol solution at 80°C. The treatment can extract lithium (Li2O) from the Li2MnO3 component in the composite of Li1.2Mn0.54Ni0.13Co0.13O2. Simultaneously, a thin layer of Al2O3 can be precipitated on the surface of the electrode particles via direct thermal decomposition of aluminum nitrates. After treatment, the first-cycle coulombic efficiency of the electrode increases from 72.1% to 93.6%, meanwhile it shows a superior cycling stability at 100mAg−1 with a discharge capacity of around 220mAhg−1 and retention of 92.5% after 100 cycles, which is much higher than that of the pristine electrode (83.2%). Even at a high current density of 2Ag−1 (10C), the discharge capacity could still achieve and well maintain as high as 140mAhg−1.