Solid electrolytes in supercapacitors

5 A typical Ragone plot for various energy storage and conversion devices. (The indicated areas are approximate only.) 

In this type of capacitor, an electric double layer is formed at the interface between the solid electrode surface and the liquid or SPE. The carbon material acquires a high capacitance due to its high surface area. Every macropore can constitute one tiny double layer and can contribute to the total capacitance. The active electrode materials used in double-layer electrochemical capacitors are carbon black, carbon cloth, carbon aerogel, etc. 

In a double-layer capacitor, no faradic reaction takes place between the electrode and electrolyte. In a pseudocapadtor, most of the charge is transferred at the interface or by the material near the surface of the electrode, which does involve a faradic reaction. The most interesting case is the conducting polymer, in which charging/discharging is possible in the material itself, raising the possibility of increasing the capacitance to a new level. 

A supercapacitor can be fabricated to have a double layer material in one electrode while the other electrode is made of pseudocapacitor material. This configuration is known as a hybrid capacitor. The strategy is used to 

There are already many solid electrolytes available that are suitable for use in a supercapacitor. Most of the recent reports say their conductivity is in the region of 10 S/cm at room temperature. ITowever, their cycling ability and outputs are the ultimate tests for practical applications. 

---

The use of solid electrolytes in supercapacitors has now been extensively studied and the results have clearly shown the variety of fabrication methods, the effects of the electrolytes, the differences between the various types of electrolyte, their interfacial resistance, their efficiency, the critical areas of concern, and so on. TEABF4 salt was found to be used in many studies, which could be due to its high conductivity, non-corrosive nature and ability to be used up to reasonably high temperatures. A balance has to be achieved between the load resistance and the internal resistance to obtain the required output. The variety in gel electrolytes has revealed some interesting results, indicating further directions for improvement. Most of the solid electrolytes were studied using pseudocapacitors. A capacitance value of... 

---