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Application of the Macrohomogeneous Line Model for the Characterization of Carbon Aerogel Electrodes In Capacitive Deionization

by Nicholas N Linneen, Frank M Delnick, Syed Z Islam, Vishwanath G Deshmane, Ramesh R Bhave
Publication Type
Journal Name
Electrochimica Acta
Publication Date
Page Numbers
1 to 7

Capacitive deionization (CDI) is a conceivable alternative desalination technology. Among the carbon
materials studied as the deionizing electrode, carbon aerogels are a promising material due to their high
surface area, structural designability and low resistivity. When evaluating carbons for CDI, their electrochemical
properties are a crucial variable making the characterization of such properties vital. In this
work we apply a macrohomogenous model to evaluate carbon aerogels activated with CO2 for various
periods and varying Resorcinol/Catalyst, R/C, ratios during synthesis for estimation of their effective
surface areas and pore sizes from an electrochemical standpoint. The porosities and structural properties
of carbon aerogels were evaluated by nitrogen porosimetry, STEM, SEM and Electrochemical Impedance
Spectroscopy (EIS). Results showed that the effective electrochemical surface areas calculated from the
EIS were a small fraction of the areas estimated by nitrogen porosimetry, indicating that primarily the
mesoporosity was utilized for deionization. Characteristic pore sizes calculated by the model were also
close to the mesopore sizes estimated by the nitrogen adsorption isotherms, STEM and SEM measurements.
Such results demonstrate the validity and value of the macrohomogenous model for evaluating
effective electrochemical properties important for CDI applications.