HIGH PERFORMANCE HYDROCARBON MEMBRANE ELECTRODE ASSEMBLY THE OBJECTIVES OF THIS PROJECT ARE TO RAISE THE PERFORMANCE AND DURABILITY OF ALL-HYDROCARBON MEMBRANE-ELECTRODE ASSEMBLIES (HC-MEAS) FOR POLYMER-ELECTROLYTE FUEL CELL (PEFC) POWERED MEDIUM- AND HEAVY-DUTY VEHICLES (M/HDVS). THE PROJECT TEAM WILL FOCUS ON THREE TANGIBLE ELEMENTS: MAKING HYDROCARBON MEMBRANES (HCMS) WITH HIGH PERFORMANCE AND DURABILITY, FINDING COMBINATIONS OF HYDROCARBON IONOMERS (HCIS), PROCESSING CONDITIONS, AND CATALYSTS (PLATINUM-GROUP METAL (PGM) NANOPARTICLES ON CARBON) THAT YIELD GOOD CATALYST LAYERS (CLS), AND INVESTIGATING HOW REPLACING SOLID PLATES (SPS) WITH POROUS WATER-TRANSPORT PLATES (WTPS) AFFECTS THE VALUE PROPOSITION FOR HC-MEAS. FOCUSING ON THESE THREE AREAS SHOULD ENABLE THE TEAM TO DEMONSTRATE POWER DENSITIES WITH HC-MEAS THAT ARE COMPETITIVE WITH STATE-OF-ART (SOA) PERFLUOROSULFONIC ACIDS MEAS (PFSA-MEAS) AT THE SAME PGM LOADING AT THE END OF 36 MONTHS. THE DURABILITY OF HYDROCARBON MEMBRANES IS WORSE THAN PFSAS. THE TEAM WILL DEPLOY A VARIETY OF STRATEGIES TO CLOSE THIS GAP INCLUDING FLUORINE-FREE REINFORCEMENTS, ORGANIC AND INORGANIC RADICAL SCAVENGERS, AND WTPS. THIS PROJECT SHOULD PROVIDE IMPORTANT NEW INFORMATION ABOUT THE EFFECTIVENESS OF THESE APPROACHES. THE PROJECT IS DIVIDED INTO TWO 18-MONTH BUDGET PERIODS, BP1 AND BP2, SEPARATED BY A QUANTITATIVE GO/NO-GO GATE REVIEW. THE HIGH-LEVEL GOAL OF BP1 IS TO DEMONSTRATE A HC-MEA WITH PERFORMANCE AND DURABILITY THAT IS COMPETITIVE WITH SOA HC-MEAS IN BOTH WTPS AND SPS, AND TO ARTICULATE A CLEAR PATH TO AN HC-MEA THAT REACHES DOE’S 2030 TARGETS. THE TEAM WILL PURSUE PERFORMANCE TARGETS AT REALISTIC TEMPERATURES, PRESSURES, AND FLOWS. REACHING THE CHALLENGING BP1 AND BP2 GOALS WILL REQUIRE THE TEAM TO DEVELOP HCMS WITH LOW RESISTANCE AND LOW H2 AND O2 PERMEABILITY. CATALYST LAYERS REQUIRE HCIS WITH HIGH CONDUCTIVITY AND H2 AND O2 PERMEABILITY. HCIS AFFORD MORE SYNTHETIC OPTIONS TO SIMULTANEOUSLY ACHIEVE LOW GAS PERMEABILITIES IN IONOMERS FOR MEMBRANES AND HIGH GAS PERMEABILITIES IN IONOMERS FOR CATALYST LAYERS THAN CONVENTIONAL PFSAS. IONOMERS THAT SWELL EXCESSIVELY IMPEDE GAS TRANSPORT IN THE MACROPORES BETWEEN AGGLOMERATES. THE TRADE BETWEEN GAS TRANSPORT IN THE MACROPORES AND THROUGH THE IONOMER NEEDS TO BE CAREFULLY BALANCED. HCIS NEED TO BE DISPERSED IN ALCOHOL/WATER MIXTURES TO FACILITATE PROCESSING AND FABRICATION, AND THE TEAM SHALL STUDY HOW SOLVENT COMPOSITION AFFECTS CL STRUCTURE AND PERFORMANCE. PFSA AND HYDROCARBON IONOMERS COAT CARBON SUPPORTS DIFFERENTLY, AND COMPREHENSIVE STUDIES SHALL BE CONDUCTED TO DETERMINE BEST CARBON/IONOMER COMBINATIONS, AS WELL AS BEST IONOMER-TO-CARBON (I/C) AND PLATINUM-TO-CARBON (PT/C) RATIOS. THE GOAL AT THE END OF THE PROJECT (BP2) IS TO REACH DOE’S TARGETS OF DEMONSTRATING 2.5 KW/GPGM POWER OUTPUT (750 MW/CM2 AT 0.7 V). A STRETCH GOAL IN LINE WITH DOE’S 2030 TARGETS IS TO ACHIEVE THIS PERFORMANCE AFTER RUNNING A HEAVY-DUTY ACCELERATED STRESS TEST (AST) EQUIVALENT TO 25,000 HOURS.