Flexible polyethylene terephthalate (PET) electrodes based on single-walled carbon nanotubes (SWCNTs) for supercapacitor application

Flexible polyethylene terephthalate (PET) electrodes based on pristine single-walled carbon nanotubes (SWCNTs) and acid-treated single-walled carbon nanotubes (A-SWCNTs) were prepared by spray coating technique. Flexible A-SWCNTs electrodes showed enhanced electrochemical properties compared to the pristine SWCNTs electrodes. The electrochemical properties of the flexible A-SWCNTs electrodes were optimized with various types of aqueous electrolytes including sulfuric acid (H₂SO₄), sodium sulfate (Na₂SO₄), potassium chloride (KCl), sodium hydroxide (NaOH), and potassium hydroxide (KOH). The electrochemical performance of the A-SWCNTs electrodes as a function of bending to 30° were evaluated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge/discharge (GCD) measurements in 1 M H₂SO₄. The specific capacitance value of the unbent A-SWCNTs electrode was 67 F g^?1, which decreased to 63 F g^?1 (94% retention) after 1000 GCD cycles. Interestingly, the specific capacitance of the unbent A-SWCNTs electrode with application of the 1000 GCD cycles was retained even after 500 bending to 30° with 6000 GCD cycles.