Caracterização de cátodos à base de filmes finos de análogos de azul da Prussia (PBAs) e mecanismo de inserção de prótons por meio de técnicas eletroquímicas e microbalança eletroquímica à cristal de quartzo(EQCM)

Abstract

The demand for the search of alternative energy sources, whether by the sustainable issue or for efficiency is becoming more frequent. Related to this, there is the obligation to store this energy in electronic devices, leading to the development of devices which are increasingly safe and at the same time have higher densities of energy and power. Nevertheless, new materials have been studied in order to ensure better characteristics for the batteries which are already on the market, besides of course having greater safety, both for the environment and for the consumer. Thus, one of the materials that are being usually studied are the Prussian Blue Analogues (PBAs) that come with the promise of being applied in proton insertion batteries and for allowing the use of aqueous solutions, beyond of course to present interesting physical chemical properties in comparison with systems containing organic electrolyte. For this eason, a deeper investigation seems important in order to explore these materials for Battery application in the future, mainly in ion insertion Battery systems in aqueous researchable systems, known as ARIBs. Therefore, this study follows a new methodology development for thin films based on PBAs on Pt electrode surface, which are CuHCF, VHCF, ZnHCF, CoHCF, MnHCF, allowing electrochemical studies in aqueous electrolytes and mechanisms comprehension. The materials characterization techniques selected were DRX, FTIR and SEM EDS for their capacity of verifying the structure and morphology of the thin films, making possible their confirmation. For the EQCM technique usage, whose principle comes from Sauerbrey’s equation for mass variation during cycling voltammograms by CV, allowing this study to understand and explore the work principle of the electrochemical mechanisms and electronic species involved. By this way, this study will serve to infer and understand the mechanisms involved in ion insertion in an aqueous 4M H2SO4 solution, which was determined that during reduction there was an insertion of species and deinserion of same species in oxidation, but all happens in one step, where Grotthus mechanism and diffusion explores the participation of H+ and even H3O+ in material structure during the electrochemical reactions with mass variation average of 25 μg.cm-2 for all materials studied.