Filmes nanocompósitos entre hexacianoferrato de zinco e nanoestruturas de carbono aplicados como materiais catódicos em baterias recarregáveis de íons zinco

Abstract

The present work describes the synthesis and characterization of nanocomposite films prepared between zinc hexacyanoferrate and carbon nanotubes (ZnHCF/CNT) and zinc hexacyanoferrate and reduced graphene oxide (ZnHCF/rGO), with subsequent application of these materials as electrodes in zinc ions battery. The synthesis of the nanocomposite films was performed according to the interfacial method using solutions of the precursor reagents (ZnCl2, K3[Fe(CN)6]), that were added in previously prepared dispersions of the carbon nanomaterials, with consequent spontaneously formation of a film at interface of the system. The results showed that all the compounds have crystalline structure, with the presence of a single rhombohedral structure phase for the films of HCFZn and ZnHCF/rGO films, however, for the ZnHCF/CNT film the presence of a secondary phase associated with the orthorhombic structure was also observed. Spectroscopic data showed the presence of both zinc hexacyanoferrate and the carbon nanomaterials in the film, and the scanning electron microscopy images reveal the interaction of these nanomaterials, being possible to observe changes in the size and morphology of ZnHCF particles according to the carbon structure used. The ZnHCF and ZnHCF/CNT films were applied as cathodic materials in zinc ion batteries. The results showed that ZnHCF/CNT film exhibited a specific capacity of 25.81 mA h g-1 and retention of 55.77 % after 200 cycles, much higher values than those obtained for the film containing only ZnHCF. In this way, the good reversibility and high potential difference for ZnHCF/CNT film make it possible to improve and develop translucent, flexible and light energy storage devices that can be used as a low-cost, safe and environmentally friendly alternative material to traditional technologies.