Measurement of internal charge distribution of electric double layer capacitor by PEA method

Abstract

In this study, electrolyte was injected into an electric double layer capacitor (EDLC) after degas treatment in vacuum and directly in air, respectively, and the internal charge distribution in the EDLC was examined by the pulsed electro acoustic (PEA) method. It was found that volume charge density in the case of injection of electrolyte after degas treatment in vacuum is about seven times compared with that injected directly in air. It was thought that sufficient electrolyte can be injected into the polarized microporous electrode by degas in vacuum and more electric charge can be saved. Moreover, the sound velocity in the material is examined. It has been understood that electrostatic capacity gradually increases with the rise of applied voltage. The electrostatic capacity was estimated by the PEA method and the energy conversion method, respectively. The results from two methods are in good agreement.