Study of electrochemical supercapacitors utilizing carbon nanotubes electrodes and PVA-hybrid polyacid electrolytes

Carbon nanotubes (CNTs) synthesized on copper and nickel alloy foil by low pressure chemical vapor deposition were employed as the electrodes of the electrochemical supercapacitors (ESs). A mixture of poly(vinyl alcohol), phosphomolybdic acid (PMA) and phosphotungstic acid (PTA) were used as the electrolyte. The surface morphology and structure of as-grown CNTs were observed by scanning electron microscope and Raman spectroscopy. The electrochemical properties of the ESs were investigated by cyclic voltammetry and galvanic charge-discharge measurements. The results showed that with the increase of PMA to 40%, the specific capacitance of the as-made ESs reaches the highest 10.7F/g.