PVP incorporated MoS2 as a Mg ion host with enhanced capacity and durability

Abstract

MoS₂ with enlarged interlayer spacing exhibits high Mg-ion storage capacity due to the accelerated kinetics of Mg²⁺, however, continuous decay of capacity occurs during the charge/discharge process, and the exfoliation of MoS₂ monolayers is observed because of the weakened van der Waal's interaction in MoS₂ interlayers. In the present study, PVP–MoS₂ nanospheres with an interlayer spacing of 0.97 nm are synthesized by a hydrothermal method, and employed as Mg-ion hosts. The characterization of MoS₂ interlayers indicates that PVP is incorporated between MoS₂ monolayers, and the former interacts with the latter to sustain the layered structure of nanospheres. PVP–MoS₂ shows a capacity of 143.4 mA h g⁻¹ at a current density of 20 mA g⁻¹, and retains 92% of the capacity after 100 cycles due to its strong structural stability. This study provides a feasible approach to prepare MoS₂ hosts with enhanced capacity and durability.