Lamellar MoSe₂ nanosheets embedded with MoO₂ nanoparticles: Novel hybrid nanostructures promoted excellent performances for lithium ion batteries

A carbon-free nanocomposite consisting of MoO₂ nanoparticles embedded between MoSe₂ nanosheets, named MoO₂@MoSe₂, has been synthesized and demonstrated excellent electrochemical properties for lithium ion batteries. In such a composite, MoSe₂ nanosheets provide a flexible substrate for MoO₂ nanoparticles; while MoO₂ nanoparticles act as spacers to retain the desired active surface to electrolyte and also introduce metallic conduction. In addition, the heterojunctions at the interface between MoSe₂ and MoO₂ introduce a self-built electric field to promote the lithiation/delithiation process. As a result, such lamellar composite has a long cycling stability with a reversible capacity of 520.4 mA h g^-1 at a current density of 2000 mA g^-1 after 400 cycles and excellent rate performance, which are attributed to the synergistic combination of the two components in nanoscale.