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

Abstract 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 Li₂MoO₃ sheets decreases gradually with increasing F doping amount, while the interlayer spacing along the z‐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.