Supercapacitors are energy storage devices with the potential to overshadow lithium-ion batteries in the energy storage sector. Generally supercapacitors store less energy than a lithium-ion battery, but make up for it with much higher power densities that allow supercapacitors to charge and discharge quickly. This can be through the formation of an electric double layer or faradaic phenomenon between the electrode and electrolyte. The energy storage mechanism relies heavily on the electrode material and the ions contained within the electrolyte. In this research, polyaniline was used as an active material to prepare supercapacitors. Polyaniline is a conductive polymer that is redox active and can be fabricated to be highly porous, making it an excellent choice for supercapacitors. It was found that a specific concentration of precursor solution containing aniline in diluted sulfuric acid could be electropolymerized at an optimized voltage of 1.21V to form an anodic deposit of polyaniline capable of 612 F/g in a half-cell with standard 1M H2SO4 electrolyte. This can be enhanced with hydroquinone as a redox mediator, causing the half-cell to exhibit 3,416 F/g on average with 0.1M hydroquinone added to the electrolyte. This design was further tested in a full cell with aqueous electrolyte and polyvinyl alcohol electrolyte. The final design iteration is a symmetric solid state supercapacitor with polyvinyl alcohol electrolyte containing hydroquinone. The completed device exhibited 307 F/g on average
