Freestanding 3D single-wall carbon nanotubes/WS2 nanosheets foams as ultra-long-life anodes for rechargeable lithium ion batteries

Tungsten disulfide (WS2) have been attracting increasing attention as anode materials for high performance lithium-ion batteries (LIBs) due to their high theoretical capacity and large interlayer spacing. However, the low conductivity and volume expansion during lithiation/delithiation process will lead to the low specific capacity and rapid capacity fading during long-term cycling. Here, we have used flexible single-wall carbon nanotubes (SWCNTs) with ultra-high electrical conductivity as conductive materials to construct a three-dimensional (3D) WS2@SWCNT foam by a simple hydrothermal method followed by freeze-drying process. The 3D structure not only provide good electronic transportation pathways, but also can accommodate huge volume change of WS2 due to the mechanical flexibility of SWCNTs, leading to the excellent cyclability as anode materials for LIBs. Benefiting from these excellent properties, the WS2@SWCNT foam nanostructure delivers a specific capacity of 1050 mAh g−1 at a current density of 0.1 A g−1, high reversible capacity of 688.3 mAh g−1 after 1000 cycles and a capacity retention of 113% over 1000 cycles at 1 A g−1.