Effect of F Dopant on the Structural Stability, Redox Mechanism, and Electrochemical Performance of Li2MoO3 Cathode Materials

摘要

F-doped Li2MoO3(LMOF) nanosheets are successfully prepared by a facile method. The X-Ray powder diffraction, scanning electron microscopy, and transmission electron microscopy results show that the thickness of the Li(2)MoO(3)sheets decreases gradually with increasing F doping amount, while the interlayer spacing along thez-axis increases. The X-ray photoelectron spectroscopy and cyclic voltammetry results indicate that F doping is helpful for suppressing the irreversible phase transformation and the formation of Li2MoO4, and the relevant redox mechanism is discussed. Moreover, density functional theory calculations demonstrate that F-doped samples exhibit a higher structural stability, which is important for the improvement of the electrochemical performance. The initial discharge capacities are 228.97, 229.74, 232.99, 238.07, and 250.07 mAh g(-1), respectively for the LMOF-0, LMOF-1, LMOF-3, LMOF-5, and LMOF-7 samples. LMOF-5 has the best performance, and it can deliver a specific capacity of 96.1 mAh g(-1)at the 500th cycle at a charge/discharge current density of 1020 mA g(-1). The experiments identify the promising role of anion doping and offer some important information for the design and optimization of Li2MoO3-based cathode materials.