Fe2(MoO4)3 nanoparticle-anchored MoO3 nanowires: strong coupling via the reverse diffusion of heteroatoms and largely enhanced lithium storage properties

Abstract

A novel hierarchical heterostructured Fe₂(MoO₄)₃@MoO₃ (FM) nanowire is developed by mild hydrothermal treatment of precursor MoO₃ nanobelts with only the assistance of FeCl₃·6H₂O combined with the heat treatment. Subsequently, a model of reverse heteroatoms diffusion is proposed to describe the formation of FM nanowires. Further, it is found that the heteroatoms diffusion and facet-selective growth of Fe₂(MoO₄)₃ on MoO₃ nanobelts brought about the change of MoO₃ morphology from nanobelts to nanowires, and Fe₂(MoO₄)₃ nanoparticles are firmly anchored onto MoO₃ nanowires. When tested as LIBs anodes, compared to pristine MoO₃ nanobelts, high reversible lithium storage capacities of the anodes are obtained from novel FM nanowires. The FM nanowire electrode obtained at 500 °C (FM-500) exhibits superior reversible capacity of 585 mA h g⁻¹ retained at a current density of 100 mA g⁻¹ after 100 cycles, and 518 mA h g⁻¹ retained after 100 cycles at 200 mA g⁻¹. The distinct electrochemical activity of the Fe₂(MoO₄)₃ nanoparticles probably activates the irreversible capacity of the MoO₃ nanobelts. Moreover, the amorphous layer and structure stability of heterojunction electrodes are also beneficial for charge storage, electron transfer and lithium ion diffusion during the charge–discharge process.