Solid polymer electrolytes have the potential to produce safer, longer-lasting alternatives to liquid-electrolyte-based lithium batteries. An alternative method to cyclic voltammetry with rotating disk electrodes has been developed to measure electrochemical reaction kinetics in solid electrolytes. This pulsed-voltammetry approach was verified by comparing to results using a rotating disk electrode with a liquid ferri/ferrocyanide redox couple. Reaction kinetics of lithium electrodes were also studied in a model solid block copolymer electrolyte. Pulsed voltammetry was applied to symmetric Li cells to measure current at different salt concentrations and temperatures. Data was analyzed with the Butler-Volmer model to obtain exchange current density and apparent transfer coefficients. The plating reaction of lithium metal was found to be significantly more sensitive to overpotential than the stripping reaction. Reaction kinetics were found to be nearly independent of salt concentration, which suggests that they are dominated primarily by the nature of the lithium metal surface. The activation energy and pre-exponential factor for the plating of lithium metal was found to be a weak function of salt concentration. These results are important for accurate modeling of the rate capability of polymer-electrolyte-based batteries and may lead to better understanding of lithium dendrite formation.

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