Determining the Porosity of Polypyrrole Membranes for Use in Potassium Air Batteries
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Date
2016-05
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The Ohio State University
Abstract
One of the biggest limitations in the implementation of renewable energies is a lack in the ability to store large quantities of electricity efficiently. One promising technology is the metal-air battery, which offers the potential for high electrochemical energy storage capacity that exceeds that of comparable metal ion batteries. Of the metal-air batteries, the potassium-air system has one of the fastest, one-electron redox processes. Currently, the fundamental limitation of potassium-air batteries is the crossover of molecular oxygen from the cathode to potassium anode, leading to the formation of potassium superoxide on the anode surface. This process reduces the availability of the metal participating in energy storage, and causes self-discharge. One solution to this problem is the introduction of a functionally graded conducting polymer membrane into the cathode to isolate the chemical reaction and minimize molecular oxygen crossover to the anode. Critical metrics to cathode construction are maximal ionic conductivity, but minimal air porosity.
The objective of this research is to obtain air porosity values for membrane materials used in the battery separator to understand oxygen transport across the cathode. To do so, a novel testing apparatus was developed with the capability to measure airflow impedance. This information is intended towards design of the cathodes for world’s first reliable potassium-air battery.
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Keywords
energy storage, metal-air battery, conducting polymer, potassium superoxide, ion transport, oxygen reduction/evolution reaction