In situ mechanical and electrical characterization of composite-integrated thin film-supercapacitors

Future transport systems will be powered more and more electrically. Generally the energy is stored in batteries. To reduce system weight and volume, multifunctional materials could be the answer. Therefore materials with the capability to store electric energy and to bear mechanical loads, need to be investigated to understand the effect of mechanical load on such structural integrated energy storage devices. In this work a thin film-supercapacitor is build up and integrated within a composite structure. The capacitor is developed to withstand the manufacturing process of a glass-fibre reinforced polymer and to carry mechanical loads, while simultaneously storing electrical energy. By using a supercapacitor housing, which is compatible to epoxy resin, a strong bonding is achieved, leading to a mechanical robust multifunctional composite. An electrolyte with large temperature window, low vapour pressure and the compatibility to a carbon based electrodes is chosen, to meet the requirement regarding the manufacturing process of the supercapacitor itself and the fibre reinforced composite. The composites with integrated thin film-supercapacitor as well as a set of reference samples are mechanically characterised in tensile and four-point bending test. In situ measurements are performed to investigate the influence of mechanical load on the electrical performance.