Ultralong SnS₂ nanobelts with a high production yield up to ∼98% were synthesized via a gram-scale and template-free solvothermal route. The synthetic mechanism of these intriguing ultralong nanobelts was proposed to be from the synergetic effect of the layered CdI₂-type structure of SnS₂ and surface-modification of the capping reagent dodecanethiol. The resulting SnS₂ nanobelts showed a high specific capacity of 640 mA h g⁻¹ and stable cycling ability (560 mA h g⁻¹ after 50 cycles), which is much better than a graphite anode.