Both the HOR and ORR electrodes were prepared using the procedure described previously . In a typical process, anion exchange ionomer (AEI) and PTFE (Ultraflon MP-25, Fuel Cell Store) were first ground with a mortar and pestle for 10 min. Following the initial grind, catalyst material was added to the mortar and the mixture was ground for again for 10 min. Next, a small amount of 18.2 M deionized water (DI) was added to the mortar and a paste was formed by further agitation with the pestle. After forming a uniform slurry, 2-propanol (IPA) was added such that the IPA:DI ratio was 9:1. The mixture was then transferred to a Teflon vortex tube. The mixture was sonicated for 60-90 min to create an ink dispersion that was sprayed onto a 25 cm 2 Toray-060 gas diffusion layer (GDL) with 5% PTFE wetproofing to create gas-diffusion electrodes (GDE). For all the experiments in this work, the anode catalyst was Pt0.25Ru0.75/pN-C and the cathode catalyst was commercial Pt/C (Alfa Aesar HiSPEC 4000, Pt nominally 40%wt., supported on Vulcan XC-72R carbon) or commercial Fe-N-C (PMF11904, Pajarito Powder LLC). The AEIs used for ionic conduction in the anode and cathode were poly(norbornene)-based copolymers whose synthesis has been described elsewhere . The anode AEI was a PGT-73 ionomer (where 78% of the monomer groups contain quaternary ammonium groups, IEC= 3.65 meq/g). The cathode AEI was a GT-32 ionomer (where 32% of the monomer groups contain quaternary ammonium groups, IEC=1.88 meq/g). In a typical anode ink preparation, the mass of ionomer, PTFE and Pt0.25Ru0.75/pN-C were 45 mg, 12 mg and 150 mg, respectively, and the volume of DI and IPA were 1 mL and 9 mL, respectively. In a typical cathode ink preparation, the mass of ionomer, PTFE, and Pt/C were 25 mg, 8 mg and 100 mg, respectively, with identical DI and IPA volumes as the anode. Following the preparation above, individual 5 cm 2 electrodes are then cut from the larger electrodes for cell testing.