Electric double layer capacitors with carbon nanotubes electrodes and gel polymer/polyacid electrolytes

Electric double layer capacitors (EDLCs) with carbon nanotubes (CNTs) film electrodes and gel polymer/polyacid electrolytes have been demonstrated. The low-cost CNTs film is directly grown on CuNi current collector by low pressure and low temperature thermal chemical vapor deposition. The electrolytes consist of gel polymer poly(vinyl alcohol), polyacid phosphomolybdic acid (PMA) with different concentrations from 10 to 40 wt.% and KCl. The electrochemical measurement of the EDLCs by cyclic voltammetry and chronopotentiometry shows that gel polymer/polyacid electrolytes can work stable at a wide potential range of -1.5 to -1.5 V and EDLCs with electrolytes containing 30 wt.% PMA exhibit optimum capacitive behavior with 8.09 F/g specific capacitance.