Study on the electrochemical characteristics of the electric double layer capacitor(EDLC) using polymer electrolyte based on porous P(VdF-co-HFP) matrix polymer

Abstract

The goal of the research in this thesis is to extend the understanding of the physics involved in the electrochemical characteristics of the polymer electrolytes based on porous P(VdF-co-HFP) matrix and to develop the noble polymer electrolytes applicable to electric double layer capacitor. A electric double layer capacitor, one of the supercapacitor, is based on the double layer capacitance at the electrode/electrolyte interface of high-surface area material such as activated carbon. With the rapid progress in the development of electric vehicles and electric devices, supercapacitors have been importantly considered as application in electric vehicles and any devices that need high-pulse discharge profile, e.g. memory backup systems, short-term backup power supplies and electromagnetic actuator. The electric double layer capacitor improves the energy storage density dramatically when compared with conventional electrolytic capacitors. When compared to batteries, the electric double layer capacitor is much less energy dense, however the power density is orders of magnitude better. And Recently, polymer electrolytes have attracted strong interest in applications for rechargeable lithium batteries, fuel cells, electrochromic devices, solar cells and chemical sensors etc., because these can lead to high reliability without leakage of the electrolyte, high energy density, and thin $film^{1-6}$. However, The use of polymer electrolytes in electric double layer capacitors has been $limited^{7-14}$, probably owing to the relatively low ion conductivity, poor mechanical properties, high processing cost and poor contact between the polymer electrolyte and the electrode inducing high equivalent series resistance(ESR). In order to overcome these problems, new method for preparing electrode based on activated carbon powder and plasticized polymer electrolytes for supercapacitor was suggested. In this method, the polymer matrix contains the dibutylphthalate(DBP) instead o...