Designing electrodes and electrolytes for energy conversion/storage integrated devices

The increasing energy request in off-grid conditions is forcing the scientific and industrial community to explore the feasibility of integrated photovoltaic (PV)-based harvesting storage devices. Among the third generation PV technologies a valuable compromise between cost, relatively high efficiency and stability is represented by the so called dye-sensitized solar cells (DSSCs), that improve their conversion efficiency under low illumination conditions. Regarding the storage section, electrical double layer capacitors (EDLCs) are reaching wide attention due to their simple configuration, long cycle life and high power density. Here we present different platforms applied for the fabrication of innovative self-powered devices integrating energy harvesting and storage sections. For the energy harvesting section, one side of the polymeric layer is adapted to enable iodide/triiodide diffusion in a DSSC, while the other side empowers sodium/chloride ions diffusion and is employed for on-board charge storage in an EDLC. The design of multifunctional polymeric layers, fabricated with two ethoxylated sections and a perfluorinated segment in between (acting as barrier, obtained by oxygen-inhibited UV-light crosslinking procedure) is also demonstrated to ease the fabrication process of planar devices. Moreover, MoS2- and Cu7S4-decorated graphene aerogels are reported as coatings for carbon fiber electrodes for the fabrication of a fiber-shaped supercapacitors. These devices provide excellent capacitance values, warranting stable performance even under high bending angle conditions. Moreover, a photocurable resin is selected as a smart packaging material to overcome stability problems usually affecting this class of devices. Flexible supercapacitors were also coupled with third-generation solar cells to successfully demonstrate the fabrication of wearable, portable, and integrated smart energy devices.