Novel Poly(Vinyl Alcohol)-Based Hydrogel Polymer Electrolyte for Electric Double Layer Capacitor

Loh, Kah Hoe (2022) Novel Poly(Vinyl Alcohol)-Based Hydrogel Polymer Electrolyte for Electric Double Layer Capacitor. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

The demand for electrochemical storage devices has surged in the past decade with people switching to portable devices, such as smartphones, smartwatches, laptops, etc., and the uprising of electric vehicles (EVs). Electrochemical storage devices typically use liquid electrolytes that have safety and longevity issues thus solid-state electrolytes have been developed in hopes of replacing them. Although solid-state electrolytes do not have the downsides of liquid electrolytes, they have substantially lower ionic conductivity compared to liquid electrolytes. Various methods have been attempted to increase the ionic conductivity of solid-state electrolytes such as adding plasticizers to make gel polymer electrolytes and adding fillers to make composite polymer electrolytes. These methods can increase the ionic conductivity but are still not comparable to liquid electrolytes and have issues of their own. In this study, mix salt system is used by adding lithium triflate to a hydrogel polymer electrolyte made of poly(vinyl alcohol) and sulfuric acid in an attempt to increase its ionic conductivity. The effects of the addition of lithium triflate are investigated and the highest conducting hydrogel polymer electrolyte is used to fabricate an electric double layer capacitor to determine its feasibility as a high-capacity electrochemical storage device and its cyclability. The addition of lithium triflate shows an increase in ionic conductivity. The cell fabricated with the hydrogel polymer electrolyte also showed high specific capacitance, energy density, and power density and has high cyclability.