Compostos Hexacianoferratos Aplicados em Baterias Aquosas de Inserção de Prótons

Resumo

Rechargeable batteries are essential for energy transition and sustainable development. Although lithiumion batteries are the most commercialized technology, other systems are constantly under development.
This work aims to study materials for application in aqueous batteries based on proton insertion. A lowcost device with high power density and greater operational safety, primarily for use in large stationary
systems. Zinc, cobalt, nickel, and manganese hexacyanoferrates (ZnHCF, CoHCF, NiHCF, and MnHCF)
were studied in an H₂SO₄ aqueous solution electrolyte. The results indicate that only NiHCF and CoHCF
are Prussian Blue analog compounds, with a cubic structure more suitable for ionic insertion reactions.
Electrochemical results show that MnHCF undergoes significant degradation in the initial charge/
discharge cycles. CoHCF and ZnHCF, while showing a good energy capacity (40 mA h g^–1) at low
charge/discharge rates (<10C), do not perform well at higher rates. Among the materials studied, the best
results were obtained with the NiHCF, which demonstrated good energy capacities even at very high
rates (50 to 25 mA h g^-1 from 0.5C - 100C), making this compound the most suitable for application in
aqueous batteries.