In an attempt to improve the efficiency of the fuel cell, we decided to change our approach to the electrode assembly. As we described in the details for this project, two liquids on either side of the membrane are at their steady state with respect to their boundary conditions. We added a flowback channel, and aim to have a diffusion rate less than that of the bipolar membrane so there is an appreciable pH difference remaining despite the diffusion. 

In order to minimize total path length for this otherwise probable event, we created a series of small holes in the bipolar membrane. The holes, spaced 4 mm apart with a diameter of .2 mm, will serve as many small flowback channels. Overall this will allow for a larger effective surface area, as flowback will be evenly spaced over the entire surface of the membrane. We hope this will show a marked improvement over other models, with the smaller path length translating into increased efficiency. 

We are currently setting up a jig that will allow us to drill holes into the bipolar membrane using a .2 mm micro bit. Using a drill bit should minimize the disruption of the membrane interface over other methods such as piercing the membrane with pins.

In addition to changing the membrane layers in the electrode assembly, there were some changes to the printed flow cell. We closed off the original center opening to the electrode assembly and added two notches opposite one another for the electrode tabs.