Conducting Polymers and Thermosensitive Hydrogels for Green Electricity Generation

Abstract

Sustainable strategies to generate electricity using natural resources, such as sunlight (photovoltaic cells) and wind (wind towers), have driven a significant change in our homes in terms of electricity consumption. Herein, a new alternative for green electricity supply using solar-driven evaporators devices fabricated with hydrogels is described. The photothermal electricity production is promoted by alginate-poly(N-isopropylacrylamide) (ALG-PNIPAAm) bio-hydrogel, modified with acid-doped conducting polymer (CP), as thermal absorber component, to minimize energy losses. Direct current and voltage monitoring are used during the solar irradiation experiments to evaluate the power density of the hydrogel thermal electricity generator, whereas electrochemical impedance spectroscopy is employed to approach the diffusion processes. Impedance measurements elucidate the ion diffusion dynamics within the hydrogel, directly correlating this behavior to enhanced power generation. Therefore, the highest power supply (64.4 μW·cm−2) and current stability (32–33 μA), over time, are obtained for ALG-PNIPAAm-PEDOT-PSS hydrogel, demonstrating that hydrophilic groups (OH, SO3H), present in the CP backbone, promote the capillary flow of the electrolyte during the sunlight irradiation. The doped CP molecules facilitate a fast ion transport thanks to a good balance between the material hydrophilicity and the interconnected pores.