Tuesday, 3 October 2017
Prince George's Exhibit Hall D/E (Gaylord National Resort and Convention Center)
Charge storage in electrochemical capacitors has been shown to be via charge separation at the electrode-electrolyte interface (so called electrical double layer charge storage) and via pseudo-capacitance, which is often described as fast redox reactions through the same interface. Charge storage via both of these mechanisms depends heavily on the interaction between the electrode morphology (electrochemically active surface area, pore size distribution, etc.) and the solvated ion in the electrolyte. In this work the interaction between a series of carbon-based substrates and various electrolyte species has been investigated.
Electrolytes examined include tetraethylammonium bis(trifluoromethane)sulfonimide (Et4NTFSI), 1-butyl-1-methylpyrrolidinium tetrafluoroborate (PYR14BF4), 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR14TFSI), and tetraethylammonium tetrafluoroborate (Et4NBF4) in acetonitrile. The interaction between these electrolytes and various carbon-based substrates was examined using a combination of cyclic voltammetry (CV) and step potential electrochemical spectroscopy (SPECS). These techniques have enabled differentiation of the charge storage mechanisms based on ion size, solvated ion size and charge density, as well as substrate surface area and porosity.