Charge storage properties of single wall carbon nanotubes/Prussian blue nanocube composites studied by multi-scale coupled electrogravimetric methods

摘要

The gravimetric and dynamic aspects of the ions transfer at SWCNT/Prussian blue (PB) composite film electrode/electrolyte interface was investigated by the electrogravimetric impedance which couples fast quartz crystal microbalance (QCM) and electrochemical impedance spectroscopy (EIS). In contact with an aqueous KCl electrolyte, evidence was found that the kinetic of species is controlled by Faraday and capacitive electrochemical charge storage mechanisms. It was found that the interfacial transfer of K+ was faster than the Cl- transfer in the studied potential window. Through our electrogravimetric method of investigation, it was revealed that both adsorption/desorption and the insertion/expulsion phenomena can occur for K+, while only adsorption/desorption can occur for Cl-. Indeed, for pure PB films, the anion contribution to the charge compensation process has never been observed in the studied medium and for that, it is related to only electroadsorption on the SWCNT part of the film. Present work highlighted tha fact that electrogravimetric response of the SWCNT/PB composite electrode encloses several species contribution probably due to a synergic effect of the two phases and our study contributes to disentangling it both gravimetrically and dynamically. (C) 2018 Elsevier Ltd. All rights reserved.