The need for creating safe electrolytes for lithium batteries is significant given the continued safety problems associated with current lithium-ion batteries. Nonflammable polymer electrolytes offer a possible solution but the rate of lithium ion transport is too low for practical applications. In this talk, I will discuss some of the fundamental factors that limit ion transport in polymers. Polymer electrolytes obey Ohm’s Law, i.e. in the limit of small applied potentials, the current generated at steady state is proportional to the applied potential. Methods for using this measurement to determine the transference number of the electrolyte will be discussed. A surprising conclusion of our analysis is that the cation transference number of most polymer electrolytes is negative. In other words, in the absence of concentration gradients, both the cation and the anion are driven by the applied electric field to the same (positive) electrode. This reduces the efficacy of batteries with polymer electrolytes. Approaches for addressing this limitation will be discussed.

Ohm’s law, polymer electrolytes and lithium batteries

253rd National Meeting (2017)

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