Few-layered MoS/C with expanding d-spacing as a high-performance anode for sodium-ion batteries.

Sodium-ion batteries (SIBs) show great potential as alternative energy storage devices for next generation energy storage systems due to the deficiency of lithium resources. MoS is a promising anode material for SIBs due to its high theoretical sodium storage capability and large interspace for accommodating sodium ions with a larger ionic radius than lithium ions. However, bulk MoS exhibits a sluggish kinetics for the intercalation-deintercalation of sodium ions and large volume expansion, which result in poor cyclability and rate performance. In this study, we designed few-layered MoS/C nanoflowers with expanded interspacing of MoS-MoS planes using polyvinyl alcohol (PVA) as an intercalating reagent and a carbon precursor. Due to the unique nanostructure and larger interlayer spacing, the MoS/C nanoflower electrode achieves a high reversible specific capacity of 400 mA h g after 300 cycles at 500 mA g for sodium-ion batteries (SIBs), showing a good cycling stability. The improved electrochemical performance suggests that the MoS/C composite is a promising anode material for sodium ion storage.