Integrated Electrochemical Energy Storage and Photovoltaic Device with a Gel Electrolyte

Integrating both electrochemical solar cells (harvesting energy) and supercapacitors (energy storage) into a single device is unquestionably one of the great challenges nowadays. There has been an extended research in the design and construction of integrated solar energy harvesting and storage systems that can simultaneously capture and store various forms of energies from nature. Here, we successfully designed, fabricated and characterized a compact and monolithically photoelectrochemical device combining a polyvinyl alcohol (PVA)/hydrochloric acid (HCl)- based gel electrolyte, multi-walled carbon nanotube (MWCNTs), and fluorine doped tin oxide (FTO) as counter and working electrodes, respectively. The combination device can act either as an independent solar cell, a supercapacitor, or as a solar cell/supercapacitor device. In this structure, energy harvesting takes place only at the working electrode (WE) that made of a thin film composite of a conducting polymer (i.e. Polyaniline, PANT) and synthetic dyes materials that coat on the FTO surface by electrochemical deposition technique. The energy storage occurs in both WE and counter electrode (CE) that made of (MWCNTs) in addition to the gel electrolyte materials. Different synthetic dyes have been used such as Methylene Blue (MB), Methyl Orange (MO), and Prussian Blue (PB). Among them, MB has shown the strongest photoelectrochemical reaction in HCl-PVA gel electrolyte. The cyclic voltammetry was used to show the effect of PANI/synthetic dyes on the cell, and impedance spectroscopy demonstrated the effect of surface modification of MWCNTs on the performance of the CE.