Improved Anion Exchange Membranes for Alkaline Fuel Cells

Anion exchange membrane fuel cells (AEMFCs) which utilize high energy density fuels and oxidants can provide long endurance energy systems for unmanned undersea vehicles (UUVs) and other Navy applications. Directly consuming a combination of a high energy density fuel (NaBH4) and concentrated liquid oxidizer (H2O2) directly rather than decomposing them into hydrogen and oxygen, then consuming them is a key to achieving much higher energy densities in a fuel cell based energy storage system. In Phase I, Lynntech demonstrated that this type of direct fuel cell can produce an output greater than is theoretically possible in a gas fed fuel cell. This was accomplished by developing two classes of anion exchange membranes (AEMs) based on different commercially available backbones both of which contained a unique, highly stable functional group. In Phase II, Lynntech will optimize the synthesis of the polymers and evaluate the properties and performance of the membranes. The down selected composition will be scaled and demonstrated in both extensive single cell tests and in a short stack operating on aqueous NaBH4 and H2O2.