Oriented SnS nanoflakes bound on S-doped N-rich carbon nanosheets with a rapid pseudocapacitive response as high-rate anodes for sodium-ion batteries

Abstract

By virtue of abundant sodium resources and low cost, sodium-ion batteries have been considered as a promising candidate compared with the prevailing lithium-ion batteries. However, substantial volume changes and sluggish sodiation kinetics limit their practical application. Here, we designed and prepared a hybrid architecture of oriented tin(II) sulfide nanoflakes bound on S-doped N-rich carbon nanosheets (SnS/CNS) via a facile sol–gel and hydrothermal route. The functional carbon nanosheets not only strengthen the interaction with SnS, but also enhance the conductivity and pseudocapacitance of the composite. This unique SnS/CNS anode delivers a high reversible capacity of 654 mA h g⁻¹ and excellent rate capabilities of 487 and 250.7 mA h g⁻¹ at current densities of 1 and 20 A g⁻¹, respectively. Further kinetic analyses reveal that the pseudocapacitive contribution accounts for fast Na⁺ storage at high rates.