(118a) Advancements in Bipolar Membrane Fuel Cells

Anionic fuel cells are a possible route to overcoming fundamental issues with acid-based fuel cells. The issues include the high cost of platinum catalysts, complex water transport, and sluggish electrochemical reactions. In particular, a bipolar membrane composed of a cation conducting material and an anion conducting material has several additional advantages because each electrode can have an optimum pH, and water can be created at the cation/anion membrane interface close to where it is consumed in the oxygen reduction reaction.

The primary areas of concern for these bipolar devices are: i) fabrication of stable bipolar membrane structures, ii) synthesis of improved anion exchange materials, and iii) development of improved catalysts for oxygen reduction in alkaline media. This work aims to combine these three objectives and optimize bipolar membrane fuel cells. Bipolar membranes utilizing a variety of junction materials have been investigated to determine the effect of cation/anion junction location on overall device performance. Additionally, anion conductive membranes have been synthesized with different block lengths and ion exchange capacities in order to maximize the ionic conductivity and understanding the relationship between chemical structures and water mobility in anion exchange membranes. Lastly, carbon nanofiber catalyst supports have been developed and functionalized to facilitate alkaline oxygen reduction.