Spatio-temporal charge behavior in electric double layer capacitors observed by pulsed electro acoustic method

Abstract

The use of the pulsed electro acoustic (PEA) method allowed us to perform the direct observations of spatio-temporal charge distributions in EDLCs based on polarizable nanoporous carbonaceous electrode. The negative charge density became the maximum, about −173 C/m 3 at the region where was near to anode layer in EDLCs for case of dc voltage 2.5 V, while the positively charged density became the maximum, about 70.7 C/m 3 at the region where it was located around the cathode layer. The behavior of negative and positive charges measured by the PEA method reflected the hetero-charges distribution in EDLCs. The performance of the sample was found to be better in terms of the capacitance ( C s) with a maximum value of 55.4 F/g than general EDLCs which use organic electrolyte.