A high-performance supercapacitor based on a polythiophene/multiwalled carbon nanotube composite by electropolymerization in an ionic liquid microemulsion

Abstract

Polythiophene (PTh) was electrochemically polymerized onto the multiwalled carbon nanotube (MWCNT) modified carbon paper by a galvanostatic method in an oil-in-ionic liquid microemulsion (O/IL). The as-prepared PTh/MWCNT composite had an interlaced framework morphology, in which the MWCNTs were uniformly coated by PTh with a thickness of 2–3 nm. The capacitive performance of the as-prepared PTh/MWCNT composite was tested in 1 mol L⁻¹ Na₂SO₄ solution. The results showed that the composite film had a favorable capacitance with a high electron transfer rate and low resistance. The highest specific capacitance could be achieved as high as 216 F g⁻¹ with the charge loading of 300 mC at a current density of 1 A g⁻¹. The PTh/MWCNT composite had a good cycle stability with a low fading rate of specific capacitance after 500 cycles. The results demonstrated the feasibility of the as-prepared PTh/MWCNT composite to be used as an electrode material for supercapacitors.