LiFePO4-Coated Li1.2Mn0.54Ni0.13CO0.13O2 as Cathode Materials with High Coulombic Efficiency and Improved Cyclability for Li-Ion Batteries

In this work, we present a new design for a surface protective layer formed by a facile aqueous solution process in which a nano-architectured layer of LiFePO4 is grown on a Li-rich cathode material, Li1.2Mn0.54Ni0.13Co0.13O2. The coated samples are then calcined at 400 or 500 degrees C for 5 h. The sample after calcination at 400 degrees C demonstrates a high initial columbic efficiency of 91.9%, a large reversible capacity of 295.0 mAh center dot g-1 at 0.1C (1C = 300 mA center dot g(-1)), and excellent cyclability with a capacity of 206.7 mAh center dot g(-1) after 100 cycles at 1C. Meanwhile, voltage fading of the coated sample is effectively suppressed by protection offered by a LiFePO4 coating layer. These superior electrochemical performances are attributed to the coating layer, which not only protects the Li-rich cathode material from side reaction with the electrolyte and maintains the stability of the interface structure, but also provides d excess reversible capacity.