Surface LiMnNiMoO Coating and Bulk Mo Doping of Li-Rich Mn-Based LiMnNiCoO Cathode with Enhanced Electrochemical Performance for Lithium-Ion Batteries.

To improve the initial Coulombic efficiency, cycling stability, and rate performance of the Li-rich Mn-based LiMnNiCoO cathode, the combination of LiMnNiMoO coating with Mo doping has been successfully carried out by the sol-gel method and subsequent dip-dry process. This strategy buffers the electrodes from the corrosion of electrolyte and enhances the lattice parameter, which could inhibit the oxygen release and maintain the structural stability, thus improving the cycle stability and rate capability. After LiMnNiMoO modification, the initial discharge capacity reaches 272.4 mAh g with a corresponding initial Coulombic efficiency (ICE) of 84.2% at 0.1C (1C = 250 mAh g), far higher than those (221.5 mAh g and 68.9%) of the pristine sample. Besides, the capacity retention of the coated sample is enhanced by up to 66.8% after 200 cycles at 0.1C. Especially, the rate capability of the coated sample is 95.2 mAh g at 5C. XRD, SEM, TEM, XPS, and Raman spectroscopy are adopted to characterize the morphologies and structures of the samples. This coating strategy has been demonstrated to be an effective approach to construct high-performance energy storage devices.