Superior lithium storage performance in MoO3 by synergistic effects: Oxygen vacancies and nanostructures

Molybdenum trioxide (MoO3) has recently attracted wide attention as a typical conversion-type anode of Li-ion batteries (LIBs). Nevertheless, the inferior intrinsic conductivity and rapid capacity fading during charge/discharge process seriously limit large-scale commercial application of MoO3. Herein, the density function theory (DFT) calculations show that electron–proton co-doping preferentially bonds symmetric oxygen to form unstable HxMoO3. When the –OH- group in HxMoO3 is released into the solution in the form of H2O, it is going to form MoO3−x with lower binding energy. By the means of both electron–proton co-doping and high-energy nanosizing, oxygen vacancies and nanoflower structure are introduced into MoO3 to accelerate the ion and electronic diffusion/transport kinetics. Benefitting from the promotion of ion diffusion kinetics related to nanostructures, as well as both the augmentation of active sites and the improvement of electrical conductivity induced by oxygen vacancies, the MoO3−x/nanoflower structures show excellent lithium-ion storage performance. The prepared specimen has a high lithium-ion storage capacity of 1261 mA h g−1 at 0.1 A g−1 and cyclic stability (450 cycle), remarkably higher than those of previously reported MoO3-based anode materials.