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

• Published in: Electrochimica acta 2018-05, Vol.271, p.297-304
• Main Authors: Escobar-Teran, F., Perrot, H., Sel, O.
• Format: Article
• Language: English
• Subjects: ac-electrogravimetry; Adsorption; Batteries; Carbon; Charge storage; Chemical Sciences; Desorption; Electrochemical impedance spectroscopy; Electrochemical quartz-crystal microbalance (EQCM); Electrodes; Electrolytes; Expulsion; Gravimetry; Microbalances; Multiscale analysis; Other; Oxidation; Pigments; Prussian blue; Single wall carbon nanotubes; Thermogravimetric analysis
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2018.03.140

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. [Display omitted] •SWCNT/Prussian blue nanocube composite shows a synergic effect on the charge storage behavior.•Ac-electrogravimetry response of the composite film encloses several species contribution.•Two types of cations, an anion and solvent with different kinetics are detected for the composites.•The different sites for electroadsorption/insertion on the composite electrode are accessible.•Present method disentangles composites' synergic effect gravimetrically and dynamically.