Abstract
Increasing reliance on electric mobile devices and vehicles has generated the need for better power supply systems to meet the demands of the user, be it a phone's battery life or vehicle range. To meet the larger power needs of these systems with limited sizes, a solution is to develop multi-functional composites that store electrical energy and provide structural support simultaneously. Composites functioning as structural supercapacitors are promising candidates with good power density, high cyclability, and safety. This thesis examines the development of new types of multi-functional materials with enhanced energy storage capabilities and mechanical properties for structural supercapacitors. The first part of this thesis focuses on the creation of a new all-solid-state polymer electrolyte that outperforms previous reports in terms of electrochemical interface and mechanical stiffness. The solid electrolytes in this study rely on the formation of a solid solution of thermoplastic polymers and lithium salts, which can have their properties altered after exposure to humidity. It was observed that altering the amount of salt in the solution, the humidity the electrolyte was exposed to, and the salt used had a significant effect on the performance of the composite. Through the alteration of these three factors, the best sample tested showed the best interfacial capacitance and highest flexural modulus reported in the literature. The second part of this thesis studies the creation of a fully functional composite structural supercapacitor composed of the solid electrolyte created in the first part of the thesis, carbon fiber electrodes, and glass fiber separator materials. Using the new solid electrolyte, the process for the creation of the multi-functional composite in lab scale was determined, and the electrochemical properties of the composite were characterized. The results lay the foundation for the future development of large-scale, practical structural supercapacitors.