Facile Synthesis of Cross-Linked Poly (Vinyl Alcohol)-Based Hydrogel Polymer Electrolyte for Electrical Double Layer Capacitor (EDLC)

Choy, Chun Wei (2023) Facile Synthesis of Cross-Linked Poly (Vinyl Alcohol)-Based Hydrogel Polymer Electrolyte for Electrical Double Layer Capacitor (EDLC). 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 flexible wearable devices, such as smartphones and smartwatches. Electrochemical storage devices commonly use liquid electrolytes that have serious safety issues therefore solid-state electrolytes have been developed to replace liquid electrolytes. Solid-state electrolytes do not have similar disadvantages like liquid electrolytes but they have substantially lower ionic conductivity compared to liquid electrolytes. Hence, solid-state electrolytes are limited for further application in electrochemical devices. 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. In this study, mix salt system is used by adding lithium triflate and sulfuric acid to a cross-linked hydrogel polymer electrolyte made of poly (vinyl alcohol) and glutaraldehyde in an attempt to increase the ionic conductivity. The effects of the addition of lithium triflate and glutaraldehyde are investigated and the highest conducting cross-linked hydrogel polymer electrolytes is used to fabricate an electric double layer capacitor to determine its performance as a high-capacity electrochemical storage device and its cyclability. The addition of lithium triflate and glutaraldehyde shows higher ionic conductivity than cross-link free hydrogel polymer electrolytes. The cell fabricated with the cross-linked hydrogel polymer electrolyte also showed high specific capacitance, energy density and power density and has very high cyclability