Multi-walled carbon-nanotube-decorated tungsten ditelluride nanostars as anode material for lithium-ion batteries

Multi-walled carbon-nanotube (MWCNT)-decorated WTe₂ nanostars (WTe₂@CNT nanocomposites) are to be employed for the first time as anode candidates in the development of lithium-ion (Li-ion) batteries. WTe₂@CNT nanocomposites deliver a high discharge capacity of 1097, 475, 439, 408, 395 and 381 mA h g^-1 with an increasing current density of 100, 200, 400, 600, 800 and 1000 mA g^-1, respectively, while WTe₂ nanostars exhibit a reversible capacity of 655, 402, 400, 362, 290 and 197 mA h g^-1 with the aforementioned current densities. Furthermore, WTe₂@CNT nanocomposites exhibit a superior reversible capacity of 592 mA h g^-1 at 500 mA g^-1 with a capacity retention of 100% achieved over 500 cycles, while bare WTe₂ nanostars deliver ∼85 mA h g^-1 over 350 cycles. This remarkable Li cycling performance is attributed to MWCNTs interconnected with WTe₂ nanostars. In addition, the exposed active interlayers of the WTe₂ nanostars, which are responsible for maintaining the structural integrity of the electrodes, buffer the large volume expansion within the WTe₂ nanostars, avoiding the agglomeration of the particles. The layered WTe₂ nanostars were synthesized via the solution-phase method, and present extremely good possibilities for the scaling-up of Li-ion battery storage systems.