Methanol fuel cell – the Band Aid Version

Here’s how you can build a methanol fuel cell, at home, from band aids, a Membrane Electrode Assembly (MEA) and some stainless steel bug screen.

So, here are the things you need:

1. Two big band aids

They will need to be plain ones, not impregnated with anything, and will need to be porous, so that the methanol can penetrate them and make the fuel cell work.

2. Stainless steel bug screen

It’s the one that protects you from flies and other monsters during the summer. You can find some at specialized fuel cell stores around the internet or at your local DIY store.

3. MEA (Membrane Electrode Assembly)

The MEA is the core part of the methanol fuel cell you’re going to build. The MEA uses a layer of a material called “Nafion” that is also known as “sulfonated tetrafluorethylene copolymer.”

The nafion piece is going to reform methanol to carbon dioxide and hydrogen without any other energy input.

The Anode side of the MEA is coated with with a mixture of Platinum and Ruthenium and the Cathode is coated with 2 milligrams of platinum.

The Membrane has a built in Gas Diffusion Layer of carbon cloth.

4. Cotton gloves

Because all MEA fuel cells are very sensitive to dirt and especially carbon remains, you have to wear a pair of gloves when handling it, or otherwise you’ll risk of ruining the cell.

Methanol fuel cell: the making of

First, you need to cut two rectangles of wire mesh, and make sure it’s a little narrower than the smallest dimension of the wound pad in the band aid, and longer than the longest dimension.

After you’ve removed the protective covering from one of the band aids, place the first wire mesh rectangle so that it sits on the inside of the “wound pad” of the band aid. The other end should go past the end of the band aid.

Remove the MEA from the bag carefully using cotton gloves.

You need to trim the MEA so that it is slightly bigger than the wound pad of your Band Aid, but so that there is still a generous border of Band Aid sticky to hold the assembly together. The MEA MUST overlap the wound pad.

The next shot displays the MEA checked for size against a Band Aid. Note that “Anode” is marked on the MEA, you need to make a note of which side “Anode” appears the correct way round on, make a note of this and put a “+” on the Band Aid facing the MEA. You might want to use an overhead projector pen to do this.

Checking the MEA for Size (Remembering Orientation)

Next lay the MEA on the wire mesh, noting orientation. Ensure that the overlap of the MEA sticks to the border of Band Aid adhesive, you need to isolate each side of the MEA from each other using the Band Aid Adhesive as a barrier.

Now take the other strip of Wire Mesh that you cut, and lay it up on the MEA so that the spare length of gauze protrudes from the opposite end.

Laying the final layer of wire mesh on top of the MEA

It’s a good idea to bend the wire gauze back on the Band Aid corresponding to the side of the MEA the gauze was in contact with. This helps remember which piece of gauze is what electrode.

Now, use a scalpel to remove a 1cm square of the “pink” bit of band aid from the side that is in contact with the “Anode” side of the MEA.

The completed methanol fuel cell

Testing the methanol Fuel Cell

A 3% methanol solution will be needed to test the fuel cell you just created. You will need to introduce the methanol solution to the patch of band air you removed on one side. The wound patch will act as a reservoir, while the other side of the fuel cell must be kept dry, to let oxygen enter through its pores.

Connect the methanol fuel cell to a multimeter and wait a bit, because the chemical process needs time to get started. If you apply a little pressure on the sides the voltage will improve.

This tutorial has used portions of text from a makezine tutorial written by Gavin D.J. Harper. All pictures (c) Gavin D.J. Harper/makezine.