In situ simultaneous encapsulation of defective MoS2 nanolayers and sulfur nanodots into SPAN fibers for high rate sodium-ion batteries

Molybdenum sulfide (MoS2) with layered structure has emerged as a promising anode material for sodium ion batteries (SIBs) in light of its particular surface chemistry and physical structures. However, the MoS2-based SIBs usually suffered from the weaknesses of the low rate capability and poor cycling stability induced by the sluggish kinetics of Na+ intercalation and the diffluent discharge products. Herein, the defective MoS2 nanocrystals and sulfur nanodots simultaneously embedded in sulfurized polyacrylonitrile (SPAN) fibers were fabricated via an electrospunning technology, followed by a simple annealing treatment. The unique architecture, in which MoS2 nanolayers and sulfur nanodots were mounted inside the SPAN fiber, provided multi-entry and short-range channel for sodium ion to ensure a fast kinetics. Besides, sulfur defects within MoS2 produced the strong chemical interaction for fixing soluble discharge products. As a result, the electrode performed outstanding sodium-storage performance with a superior long cycling life (8000 cycles at 5 A g(-1), 15,000 cycles at 10 A g(-1)) and excellent rate capability (212 mAh g(-1) at 25 A g(-1)). The full cell fabricated by using Na3V2(PO4)(3) as the cathode also delivered good energy storage performance and successfully powered a group of light-emitting diode.

Automated summary

The composite material of molybdenum sulfide and sulfur fabricated using electrospinning technology shows excellent performance in sodium ion batteries, with high cycling life and outstanding rate capability.