Karim, Alamgir2023-01-01August 2022022-08-15https://hdl.handle.net/10657/13251Due to the fast development in portable, flexible, and wearable electronic devices, it is vital to develop high-performance energy storage devices. Among these various energy storage systems, batteries and Supercapacitors are the two key technological systems holding a broad range of applications. Supercapacitors (SCs) have a higher power density than batteries. Also, they exhibit longer cycling life and better safety. Supercapacitors with gel polymer electrolytes are lightweight and flexible. Hence, they can show a great potential in which we need power sources for flexible, portable electronics. In this thesis, a flexible, lightweight, safe, and flame-retardant supercapacitor was fabricated, and the effects of molecular weight and supporting salt were studied. Characterization results indicate that PVA polymer with a molecular weight of 47000 presents higher ionic conductivity. The reason is attributed to the free volume theory. Since, in polymers with lower molecular weight, polymer chains are shorter and present more movement. Moreover, characterizations showed that gel polymer electrolytes with higher molecular weight provided a transparent and uniform structure. Stress-strain plots indicated that PVA with higher molecular weight provided higher mechanical stability. Also, the fabricated supercapacitor presented excellent ionic conductivity of 1.7 s/cm and specific capacitance of 100 after 1000 cycles. Moreover, results indicated capacity retention of 100%. In addition, experiments showed that adding boric acid to the gel polymer electrolyte improved electrochemical performance. Current challenges and future perspectives are also discussed.application/pdfengThe author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).SupercapacitorsPVAPolymerEnergy storage devices2023-01-01Thesisborn digital