Synthesis and electrochemical performance of nano TiO2(B)-coated Li[Li0.2Mn0.54Co0.13Ni0.13]O2 cathode materials for lithium-ion batteries†
Lithium-rich layered metal oxides are of particular interest as next-generation cathode materials for advanced Li-ion batteries because of their high energy density and voltage plateau. Various challenges, such as large initial irreversible capacity, inferior cycling stability and fast voltage decay, have hindered their practical applications. Inspired by good chemical and thermal stability of TiO2(B) with organic electrolytes, we report here a series of TiO2(B)-coated Li[Li0.2Mn0.54Co0.13Ni0.13]O2 (LMCNO) composites to increase the electrochemical performance of LMCNO cathode materials. Compared with the pristine LMCNO sample, the TiO2(B)-coated LMCNO composites show a higher reversible capacity, better cycling stability and rate capability. Among them, the 5 wt% TiO2(B)-coated LMCNO composite shows a high initial capacity of 258.3 mA h g−1, a good capacity retention of 75% after 80 cycles at 0.1C, and an outstanding rate capability of 105 mA h g−1 even at a high rate of 5C. Notably, the initial Coulombic efficiency is enhanced and voltage fading is alleviated effectively by TiO2(B) coating even after 400 cycles at 2C. The enhanced electrochemical properties can be attributed to the interface interaction between the TiO2(B) layers and the surface of LMCNO and the improved thermal stability of TiO2(B)-coated LMCNO composites.