Rapidly Synthesized, Few-Layered Pseudocapacitive SnS₂ Anode for High-Power Sodium Ion Batteries

The abundance of sodium resources has recently motivated the investigation of sodium ion batteries (SIBs) as an alternative to commercial lithium ion batteries. However, the low power and low capacity of conventional sodium anodes hinder their practical realization. Although most research has concentrated on the development of high-capacity sodium anodes, anodes with a combination of high power and high capacity have not been widely realized. Herein, we present a simple microwave irradiation technique for obtaining few-layered, ultrathin two-dimensional SnS₂ over graphene sheets in a few minutes. SnS₂ possesses a large number of active surface sites and exhibits high-capacity, rapid sodium ion storage kinetics induced by quick, nondestructive pseudocapacitance. Enhanced sodium ion storage at a high current density (12 A g^-1), accompanied by high reversibility and high stability, was demonstrated. Additionally, a rationally designed sodium ion full cell coupled with SnS₂//Na₃V₂(PO₄)₃ exhibited exceptional performance with high initial Coulombic efficiency (99%), high capacity, high stability, and a retention of ∼53% of the initial capacity even after the current density was increased by a factor of 140. In addition, a high specific energy of ∼140 Wh kg^-1 and an ultrahigh specific power of ∼8.3 kW kg^-1 (based on the mass of both the anode and cathode) were observed. Because of its outstanding performance and rapid synthesis, few-layered SnS₂ could be a promising candidate for practical realization of high-power SIBs.