A tin(II) sulfide-carbon anode material based on combined conversion and alloying reactions for sodium-ion batteries

A tin(II) sulfide carbon (SnS-C) nanocomposite is prepared by a simple high-energy mechanical milling method. XRD, SEM and TEM characterizations show that the nanocomposite is composed of well crystallized SnS nanoparticles with a size of about 15 nm, which are dispersed uniformly in the conductive carbon matrix. The SnS-C electrode exhibits a high Na storage capacity (568 mA h g(-1) at 20 mA g(-1)) and excellent cycling stability (97.8% capacity retention over 80 cycles) as well as high-rate capability. Ex situ XRD result confirms a sequential conversion and alloying dealloying reaction mechanism of the SnS C electrode during the Na uptaking and extraction cycles. The superior electrochemical performance of the electrodes can be attributed to the small crystalline size of SnS and good carbon coating, which facilitate electrochemical utilization and maintain the structural integrity.