Morphology design and electronic configuration of MoSe anchored on TiO nanospheres for high energy density sodium-ion half/full batteries.

Molybdenum selenide (MoSe) has shown potential sodium storage properties due to its large layer spacing (0.646 nm) and high theoretical capacity and narrow band gap. However, as the anode material of sodium ion batteries (SIBs), the MoSe's performance is not ideal, especially due to the layer agglomeration and stacking caused by volume expansion and low intrinsic conductivity. Hence, morphology design and electronic configuration of MoSe is proposed via building MoSe nanosheets and auxiliary sulfur doping on the surface of the TiO hollow nanosphere (S-MoSe@TiO). The hierarchical shaped S-MoSe@TiO effectively overcomes the shortcomings of high surface energy and weak interlayer van der Waals force of MoSe. As anode for SIBs, S-MoSe@TiO delivers enhanced cycling life and rate capability (308 mAh/g at 10 A/g after 1000 cycles) with the comparison of MoSe@TiO or pure MoSe and TiO. Such excellent sodium storage performance is due to the fast diffusion kinetics of Na. When it is applied in sodium ion full batteries, the S-MoSe@TiO anode based cell can reach a high energy density of 187.8 W h kg at 148.3 W kg. The design of the new MoSe-based hybrid provides a novel scheme for the preparation of advanced anode in SIBs.