The cell was then assembled in a zero-gap configuration, with a cathode and anode sandwiched tight up against opposite sides of a fast-wicking polyethersulfone (PES) separator membrane with 8 m average pore diameter ('8 m PES'). The bottom end of the PES separator extended out the bottom of the cell, as shown in the exploded view in Figure . until it had a net loading of 0.5 mg cm -2 Pt. The cathode was prepared using the preparative procedure of Hodges and co-workers, which was based on one previously reported by Masel and colleagues. The cathode is designated in this work as: 'Pt/C/Nafion/CFP'. It was maintained in direct electrical contact with a perforated Ni bipolar plate and a gas-tight cathode compression bolt, by screwing in the compression bolt, as shown in Figure . After assembly of the cell, a torque of 25 N cm was applied to the compression bolt to compress the Ni bipolar plate against the cathode, which was then, in turn, compressed against the PES separator.