Flexible additive-free CC@TiOxNy@SnS2 nanocomposites with excellent stability and superior rate capability for lithium-ion batteries

Abstract

A novel material consisting of metal oxide–nitride (TiO_xN_y nanowires) and metal sulfide (SnS₂ nanosheets) is synthesized on a flexible carbon cloth substrate by a two-step hydrothermal reaction. The as-synthesized carbon cloth/titanium oxynitride/tin disulfide (CC@TiO_xN_y@SnS₂) nanocomposites are tested directly as additive-free anode materials for lithium-ion batteries. The free-standing CC@TiO_xN_y@SnS₂ electrode displays an initial discharge capacity of 1082 mA h g⁻¹ at a current density of 1C, with a coulombic efficiency of 74%. The reversible capacity as high as 612 mA h g⁻¹ can still be maintained after 100 charging/discharging cycles. Moreover, this material shows outstanding rate properties with a high reversible discharge capacity of 419 mA h g⁻¹ at a current density of 5C, which is higher than the theoretical capacity of graphite. Also, a stable high discharge capacity of 676 mA h g⁻¹ can be attained when the current density is switched back to 1C. The high electrochemical performance can be attributed to the high electrical conductivity of the TiO_xN_y, which facilitates the transport of electrons and lithium ions, and the unique layer structure of SnS₂.