| Summary: | The objective of this thesis is to develop a framework for the characterization and
performance projection of new electrochemical capacitor electrode materials. This
framework was demonstrated on a new commercial electrode, called
EXCELLERATOR®, from W.L. Gore & Associates, Inc. The electrode was tested in a
Schlenk-type apparatus using cyclic voltammetry in a 0.5M tetrabutylammonium
hexafluorophosphate in propylene carbonate solution. A macroscopic homogeneous
volume averaged model was used to simulate the cyclic voltammetry response of the
electrode. Subsequent fitting of the simulated response to the experimental data gave
estimates of the volumetric capacitance and time constant of the electrode to be 40F/cm³
and 133.4s, respectively.
Analytical solutions for the terminal voltage, energy density and power density were
derived for the constant current discharging of a complete electrochemical capacitor. The
evolution of the terminal voltage during discharge was explained. The energy and power
densities for discharging the capacitor of different electrode thicknesses and at different
current densities were investigated. The observed trends were explained by comparing
the relative utilization of the electrode. The maximum energy density that can be
extracted from an electrochemical capacitor during different lengths of time was
simulated. It was shown that the thinner electrodes have higher energy and power
densities at short times because of the lower unused active material mass. For long times,
the thicker electrodes are superior because their active material mass is a larger fraction
of the total mass. It was shown that the ultimate electrode geometry would involve thin
electrodes with negligible non-active material masses. In this case, the thinnest
electrodes would have higher energy and power densities than thicker ones even at long
times. === Applied Science, Faculty of === Electrical and Computer Engineering, Department of === Graduate
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