In situ electrodeposition of polypyrrole onto TaSe2 nanobelts quasi-arrays for high-capacitance supercapacitor.

ABSTRACT

Transition metal dichalcogenides have recently revealed interesting physical properties which lead to promising applications for functional devices. TaSe2, as a member of transition metal dichalcogenides, attracts a great deal of attention as a layered electric conductor with low dimension and metallic nature. Herein, we prepare a three-dimensional conductive quasi-array based on 2H-TaSe2 nanobelts, which are synthesized directly on a tantalum foil by one step surface-assisted chemical vapor transport method. The conductive quasi-arrays are used as substrate for in situ electrodeposition of polypyrrole to form cylinder-like composite nanostructures. It is shown that the TaSe2 nanobelts can improve conductivity and stability of polypyrrole by acting as conductive and robust skeleton. A symmetric supercapacitor constructed from the composites demonstrates high areal capacitance of 835 mF cm-2 at a scan rate of 2 mV s-1, wide potential window of 1.2 V, and excellent cycling stability with 98.7% capacitance retention after 10 000 cycles. Meanwhile, the assembly process of the supercapacitor is quite simple because it does not need any additional current collector, binder or conductive additive. The nanocomposites have been verified to be a very effective way to improve electrochemical performance of polypyrrole, and are promising to be applied as supercapacitors.