SnS nanosheets on carbon foam as a flexible anode platform for rechargeable Li- and Na-ion batteries

Recently, there have been many demands for flexible and wearable electronic devices; this has resulted in comparable numbers of demands for flexible rechargeable batteries as a power source. In this study, we propose a carbon-coated SnS nanosheet on flexible carbon foam composite materials as anodes for Li- and Na-ion batteries. To fabricate the flexible electrode, we first carbonized a piece of melamine foam under an inert atmosphere. Then, SnS nanosheets were precipitated onto the foam using a simple solvothermal method. Finally, thin carbon coating layers were formed to further enhance the electrochemical properties as electrodes. The materials were characterized with X-ray diffraction; electron microscopy; and Raman and X-ray photoelectron spectroscopies. The formation of SnS nanosheets and carbon coating layers was confirmed. An electrochemical test demonstrated that a high reversible capacity of 747 mAh g−1 was maintained after 100 cycles in Li-ion cells and a capacity of 318 mAh g−1 was obtained after 50 cycles in Na-ion cells with good rate capabilities. The results could be attributed to microstructure design with carbon foam to buffer volume change and enable fast electronic/ionic transport. The flexibility of the electrode was guaranteed by the flexible carbon foam substrate without any conducting agent and binder.