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

ABSTRACT

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.