Effect of MgO and TiO2 Coating on the Electrochemical Performance of Li-Rich Cathode Materials for Lithium-Ion Batteries

摘要

0.5Li(2)MnO(3)center dot 0.5LiNi(0.5)Mn(0.3)Co(0.2)O(2) cathode materials with nano-MgO and nano-TiO2 coating layers are synthesized via a facile approach. These nanocoating layers with a thickness of approximate to 20 nm are homogeneously coated on the surface of the materials. With the nano-MgO and nano-TiO2 coating layers, the modified materials deliver excellent electrochemical performance. Nano-MgO-coated and nano-TiO2-coated Li-rich materials exhibit 147.56 and 137.96 mAh g(-1) after 100 cycles at 1C rate and deliver 156.13 and 130.69 mAh g(-1) at 2C rate, respectively, in the voltage range of 2.0-4.8 V. The materials with nano-MgO and nano-TiO2 coating layers also show a high discharge voltage retention of more than 90% after 50 cycles, low impedance for Li+ migration, and high diffusion coefficients of the lithium ions. Nano-MgO and nano-TiO2 coating layers help decrease the content of Li2CO3 on the surface of the materials and suppress side reactions. Thus, these materials play a significant role in strengthening the electrochemical performance of Li-rich cathode materials.