Investigating solid-state supercapacitors constructed with PVA/CNT nanocomposite electrolytes

Abstract

The search for alternative energy generation methods requires development for new energy storage methods as well. The ability to use nanotechnology to achieve high surface area, which is correlated to increased energy storage, brought advancements in supercapacitor applications. Supercapacitors have the potential to charge and discharge quickly and hold as much energy as batteries and other chemical storage devices. By having a completely solid-state supercapacitor, problems with leakage and decay could be avoided. Supercapacitors were assembled from electrodes made by reducing graphene oxide in a computer disc drive and adhering two electrodes with composite electrolytes having various concentrations of PVA/CNT. Tests were performed on the completed supercapacitors, as well as the individual components. The analysis of the different concentrations of carbon nanotubes in PVA electrolytes showed the lowest resistivity for 0.5wt% CNT (294 Omega cm) and the highest specific capacitance for 1.0wt% CNT (123.5 F/g). This specific capacitance is a 27% improvement on an electrolyte without CNT. The electrolyte with pure PVA has similar capacitance to other solid-state supercapacitors in the literature. Electrolytes with higher percentages of CNT (0.5%) show higher resistivity because of the decreased carbon solubility or agglomerations. The final product supercapacitors, thin, flexible, and environmentally friendly, can be used in wide temperature ranges, and have a theoretically long lifespan. They can charge more quickly than batteries, and hold more energy than capacitors. This study shows promising enhancements in solid-state supercapacitors, making them an even more plausible replacement for batteries in the near future. The improvements made on the specific capacitance with the different electrolytes could lead to greater efficiency and lower cost in many unique applications requiring absence of liquid components.