A bi-polar electrode having ion exchange polymers on opposite faces of a porous substrate is formed using a method that includes providing an electrode substrate with activated carbon layers on opposite faces of the electrode substrate, wherein said faces have an outer perimeter band void of the activated carbon layers. Gaskets are placed against the outer perimeter band of the electrode substrate void of activated carbon and the electrode substrate is clamped between two rigid plates to form a first airtight chamber on one side of the electrode substrate and a second airtight chamber on the opposite side of the electrode substrate. A first polymerizable monomer mixture having an anion exchange group is added into the first chamber and a second polymerizable monomer mixture having a cation exchange group is added into the second chamber. The first and second polymerizable monomer mixtures are then polymerized in an oven.