| To gain a better understanding of the dynamic behavior of electronically conducting polypyrrole and to provide guidance toward the design of new secondary batteries based on this polymer, two mathematical models have been developed; one for the potentiostatically controlled switching behavior of a polypyrrole film, and one for the galvanostatically controlled charge/discharge behavior of the lithium/polypyrrole secondary battery cell.; The first model is used to predict the profiles of electrolyte concentration, charge state, and electrochemical potentials within the thin polypyrrole film during the switching process as functions of applied potential and position. Thus, the detailed mechanisms of charge transport and electrochemical reaction can be understood. Sensitivity analysis is performed for the independent parameters, describing the physical and electrochemical characteristic of a polypyrrole film, to verify their influences on the model performance. The values of the independent parameters are estimated by comparing model predictions with experimental data obtained under similar conditions.; The second model is used to predict the profiles of electrolyte concentration, charge state, and electrochemical potentials within the battery system during the charge and discharge processes as functions of time and position. Energy and power densities are estimated from the model predictions and compared with the respective values of existing battery systems. The independent design criteria on the charge and discharge performance of the cell are provided by studying the effects of the design parameters. |
