Study of Prussian Blue (PB) films by ac-electrogravimetry: influence of PB morphology on ions movement

The electrochemical response of Prussian Blue films in NaCl solutions was studied. It was proved that the stability with cycling of PB films increased when these films are covered with a Nafion(R) membrane. This fact allows PB films to be studied in NaCl solutions under steady state conditions by impedance spectroscopy and ac-electrogravimetry. A model, which can explain the differences between the electrochemical behaviour of amorphous PB films and crystalline PB films in NaCl solutions, is proposed. This model is based on the hypothesis of a partial dehydration of the sodium ions before the electrochemical reactions take place, allowing the transport of sodium ions through the zeolitic channels of Prussian Blue. (C) 2000 Elsevier Science Ltd. All rights reserved.