Three-Dimensional Interconnected Spherical Graphene Framework/SnS Nanocomposite for Anode Material with Superior...

Three-dimensional (3D) interconnected spherical graphene framework-decorated SnS nanoparticles (3D SnS@SG) is synthesized by self-assembly of graphene oxide nanosheets and positively charged polystyrene/SnO₂ nanospheres, followed by a controllable in situ sulfidation reaction during calcination. The SnS nanoparticles with diameters of ∼10-30 nm are anchored to the surface of the spherical graphene wall tightly and uniformly. Benefiting from the 3D interconnected spherical graphene framework and subtle SnS nanoparticles, the generated Li₂S could keep in close contact with Sn to make possible the in situ conversion reaction SnS + 2Li⁺ + 2e^- ↔ Sn + Li₂S. As a result, the 3D SnS@SG as the anode material for lithium ion batteries shows a high initial Coulombic efficiency of 75.3%. Apart from the irreversible capacity loss of 3D spherical graphene, the initial Coulombic efficiency of SnS in the 3D SnS@SG composite is as high as 99.7%, demonstrating the almost complete reversibility of Li₂S in this system. Furthermore, it also exhibits an excellent reversible capacity (800 mAh g^-1 after 100 cycles at 0.1 C and 527.1 mAh g^-1 after 300 cycles at 1 °C) and outstanding rate capability (380 mAh g^-1 at 5 °C).