Acetylene black incorporated three-dimensional porous SnS2 nanoflowers with high performance for lithium storage

Abstract

Acetylene black incorporated porous 3-dimensional (3D) SnS₂ nanoflowers have been successfully synthesized via a simple solvothermal route assisted by polyethylene glycol. The composites are composed of acetylene black adorned SnS₂ secondary microspheres with diameters of around 2–3 μm, which are assembled from a number of nanosheets with thicknesses of 20–50 nm. The nanocomposites possess a large specific surface area of 129.9 m² g⁻¹ and a high conductivity of 0.345 S cm⁻¹. As anode materials for lithium ion batteries, the nanocomposites show high cyclability and rate capability and deliver an average reversible capacity as high as 525 mAh g⁻¹ at a current density of 400 mA g⁻¹ over 70 cycles. The high electrochemical performance can be attributed to the synergistic effect of acetylene black and the unique microstructure of SnS₂. The acetylene black serves as not only a conductive agent to accelerate the transfer of electrons in the composites, but also as a buffer matrix to restrain the volume change and stabilize the electrode structure during the alloying/dealloying process. The porous structure of SnS₂ also helps to stabilize the electrode structure and facilitates the transport for lithium ions.