La2O3-coated Li1.2Mn0.54Ni0.13Co0.13O2 as cathode materials with enhanced specific capacity and cycling stability for lithium-ion batteries

Li-rich layered oxides are the most promising cathode candidate for new generation rechargeable lithium-ion batteries. In this work, La2O3-coated Li1.2Mn0.54Ni0.13Co0.13O2 cathode materials were fabricated via a combined method of sol-gel and wet chemical processes. The structural and morphological characterizations of the materials demonstrate that a thin layer of La2O3 is uniformly covered on the surface of Li1.2Mn0.54Ni0.13Co0.13O2 particles, and the coating of La2O3 has no obvious effect on the crystal structure of Li-rich oxide. The electrochemical performance of La2O3-coated Li-rich cathodes including specific capacity, cycling stability and rate capability has been significantly improved with the coating of La2O3. The Li1.2Mn0.54Ni0.13Co0.13O2 coated with 2.5 wt% La2O3 exhibits the highest discharge capacity, improved cycling stability and reduced charge transfer resistance, delivering a large discharge capacity of 276.9 mAh g−1 in the 1st cycle and a high capacity retention of 71% (201.4 mAh g−1) after 100 cycles. The optimal rate capability of the materials is observed at the coating level of 1.5 wt% La2O3 such that the material exhibits the highest discharge capacity of 90.2 mAh g−1 at 5 C. The surface coating of La2O3 can effectively facilitate Li+ interfacial diffusion, reduce the structural change and secondary reactions between cathode materials and electrolyte during the charge-discharge process, and thus induce the great enhancement in the electrochemical properties of the Li1.2Mn0.54Ni0.13Co0.13O2 materials.