Desenvolvimento de filmes nanocompósitos entre análogos do azul da Prússia e nanotubos de carbono para aplicação em baterias de inserção iônica

Abstract

The present work describes the synthesis and characterization of nanocomposite films formed between Prussian blue analogues (PBA) and carbon nanotubes (CNT), with subsequent application of these materials as electrodes in ionic insertion batteries. The PBAs synthesized were cobalt hexacyanoferrate (CoHCF), nickel hexacyanoferrate (NiHCF) and copper hexacyanoferrate (CuHCF). The synthesis of the nanocomposite films was performed in a single step according to the liquid-liquid interfacial route. From the characterization of the prepared films, the results indicated the formation of all the proposed PBAs, all presenting a cubic crystalline structure with the presence of interstitial water molecules. Spectroscopic data and electron microscopy images showed the organization, formation and interaction between PBA nanoparticles and CNTs. All films were evaluated for performance under different conditions, varying the support electrolyte, concentration and pH variation and later, under the best conditions, they were evaluated for applicability as cathodic materials in ionic insertion batteries. The results revealed that the NiHCF/CNT film showed higher values in the insertion of monovalent ions in relation to the CuHCF/CNT film, reaching specific capacity values of 152 mA h g-1 and 212 mA h g-1 for the insertion of Na+ and K+ ions, respectively. High specific capacity values were observed for the insertion of Al3+ ions for all prepared materials, being 103,4 mA h g-1 for CoHCF/CNT, 89.3 mA h g-1 for NiHCF/CNT and 85.5 mA h g-1 for the CuHCF/CNT. In this sense, the physical characteristics and electrochemical properties of the synthesized films make it possible to improve and develop lighter and more flexible energy storage systems that can be used as a low-cost, safe and environmentally friendly alternative to traditional technologies.