The role of water and temperature in the electrochemical behavior of solid iron(III) hexacyanoferrate(II/III)

The influence of temperature over the range from −30 to 25°C on the electrochemical properties of solid iron(III) hexacyanoferrate(II/III) containing various amounts of water has been studied by means of cyclic voltammetry and impedance spectroscopy. The system studied is a water-insoluble mixed-valence coordination compound. The experiments have shown in major role for water molecules in the charge transport across this solid system. An attempt has been made to understand the experimental data on the basis of an existing model of redox conductance in solid mixed-valence transition metal hexacyanoferrates. The activation energy of charge migration in a partially dehydrated system and the activation energy of charge diffusion in a well-hydrated system have been determined.