LiFePO4-Coated Li1. 2Mn0. 54Ni0. 13Co0. 13O2 as Cathode Materials with High Coulombic Efficiency and Improved Cyclability for Li-Ion Batteries

摘要: 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°C for 5 h. The sample after calcination at 400°C demonstrates a high initial columbic efficiency of 91.9%, a large reversible capacity of 295.0 mAh·g-1 at 0.1C (1C=300 mA·g-1), and excellent cyclability with a capacity of 206.7 mAh·g-1after 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 excess reversible …