Flexible Paper-like Free-Standing Electrodes by Anchoring Ultrafine SnS₂ Nanocrystals on Graphene Nanoribbons for High-Performance Sodium Ion Batteries

Ultrafine SnS 2 nanocrystals–reduced graphene oxide nanoribbon paper (SnS 2 –RGONRP) has been created by a well-designed process including in situ reduction, evaporation-induced self-assembly, and sulfuration. The as-formed SnS 2 nanocrystals possess an average diameter of 2.3 nm and disperse on the surface of RGONRs uniformly. The strong capillary force formed during evaporation leads to a compact assembly of RGONRs to give a flexible paper structure with a high density of 0.94 g cm –3 . The as-prepared SnS 2 –RGONRP composite could be directly used as free-standing electrode for sodium ion batteries. Due to the synergistic effects between the ultrafine SnS 2 nanocrystals and the conductive, tightly connected RGONR networks, the composite paper electrode exhibits excellent electrochemical performance. A high volumetric capacity of 508–244 mAh cm –3 was obtained at current densities in the range of 0.1–10 A g –1 . Discharge capacities of 334 and 255 mAh cm –3 were still kept, even after 1500 cycles tested at current densities of 1 and 5 A g –1, respectively. This strategy provides insight into a new pathway for the creation of free-standing composite electrodes used in the energy storage and conversion.