SnS2-Graphene Nanocomposite for Advanced Lithium-Ion Battery

High-performance rechargeable lithium-ion batteries (LIBs) are indispensable for this energydemanding society. The currently commercialized anodes and cathodes suffer from relatively low theoretical capacities and energy/power densities, and therefore it is difficult to meet the increasing demands for more advanced energy storage systems. Hence, it is essential to design and synthesize new anode materials with elevated capacity, enhanced energy/power densities for rechargeable LIBs. SnS2 is one of the important anode materials for rechargeable LIBs with relatively large surface area offered by special nanostructures. However, bulk SnS2-based anode materials suffer from large volume expansion/contraction accompanying with sharp capacity fading that occur during continuous charge/discharge. Fabricating SnS2/carbon nanocomposites is one of the most popular approaches being pursued to overcome these issues and to improve the cycle life and rate capability of SnS2-based electrodes. The carbon phase can help to increase the electronic conductivity of the electrode; it can also act as a buffer to reduce of the volume changes during charge/discharge, and improve the cycle life and enhance rate performance for rechargeable LIBs. Herein, SnS2 nanoparticles were ubiquitously grown on graphene sheets by a simple one-step hydrothermal strategy (Figure 1). The electrochemical performance was evaluated as the anode for rechargeable LIBs after thermal treatment in an Ar environment. The electrochemical performance results show a high reversible capacity of more than 800 mAh g at the first cycle at a 0.1C rate. The discharge capacity of the second cycle was measured to be 772 mAh g, which is still higher than the reported theoretical value for SnS2. At the tenth cycle, the reversible capacity remains at about 662 mAh g, which is much higher than the capacity of pure SnS2 and RGO components (Figure 2). This electrochemical behavior can be attributed to the unique morphology and micro-structure of the as-synthesized nanocomposite, and synergistic effects of the different components in the nanocomposite, indicating that these nanocompsite is a promising anode material for rechargeable LIBs.