Hydrogen is expected as the ultimate clean energy carrier that can transform fossil-fuel dependent economy into a hydrogen economy. PEFC or Polymer Electrolyte Fuel Cell is the most promising application for the use of hydrogen energy. Various national R&D projects on PEFC have been being conducted by NEDO over the 20 years. Through these activities, PEFC is in the stage of practical use. Micro-Combined Heat and Power, or “Ene-Firm”, has been on market since 2009 and Fuel Cell Vehicle is going to be launched in 2015 by Japanese automakers. Toward the expansion of dissemination of PEFC, there are issues to be addressed such as cost reduction, improving durability and performance, etc. This paper introduces policy trends related to hydrogen energy of Japan, and also current activities of national R&D project on PEFC.
High performance electrodes with low Pt loading are necessary since further cost reductions are required on future PEFC system. The performance of PEFCs depends greatly on the microscopic structure characteristics of electrodes. The strong impacts on fabrication process towards electrode performance are clearly observed in decreasing Pt loading on electrodes. Electrodes are manufactured from catalyst ink. Catalyst ink is a multi-component system, consisting of catalyst carbon, ionomers, and solvent. In this study, we employed Contrast-Variation Small-Angle Neutron Scattering (CV-SANS), 19Fluorine Nuclear Magnetic Resonance Spectroscopy (19F-NMR), and Scanning Transmission X-ray Microscopy (STXM) to unveil the structure of catalyst ink and that of electrodes to discuss the relationship between fabrication process of the electrodes and its microscopic structure for high performance PEFCs.
Electric generation by a polymer electrolyte fuel cell requires an appropriate quantity of water to help ensure proton conductivity of the membrane electrode assembly. However, excess water in the gas channels and the gas diffusion layer is thought to be a factor impeding gas supply, so it is necessary to appropriately control the water inside the fuel cell during electric generation for the achievement of high performance fuel cell. This study used neutron radiography to observe the state of the water accumulated in a fuel cell during electric generation in order to clarify the mechanism by which water accumulates and its effect on voltage behavior. Observation using neutron radiography was performed from the two directions of the through-plane direction and the in-plane direction of the fuel cell. Based on these results, the optimum generation environment was set and applied to the control of an actual vehicle.
Dissemination of the fuel cell vehicles (FCV) is one of the key issues for preservation of the environment on earth, especially for reduction of greenhouse gasses. Standardization of the those technologies is important to develop the market growth of FCV. This paper reviewed the progress of the research activities on evaluation of the impurities in the hydrogen fuel for FCV as well as the standardization activities. The International Standard ISO14687-2 which was for the FCVs in limited production level was published in 2012. This international standard is also going to be revised because some of the items need to be reviewed for the mass production stage which will come in years before next decade.
Fuel cell is a source of ultimate clean energy, because it utilizes clean hydrogen as a fuel and produces only water as a by-product. The system, therefore, can be one of the essential alternative generations in view of urgent global environmental issues. This paper presents a newly developed stainless steel foil “NSSMC-NAR-316BC” for bipolar plates of PEFCs (Polymer Electrolyte Fuel Cell). The developed one provides both excellent corrosion resistance as well as superior electrical conductivity.
The principle and application of Polymer Electrolyte Fuel Cell (PEFC) and the role of polymer electrolyte membrane (PEM) were explained. The common example of PEM is perfluorinated membrane and its current status and problem have been reviewed. The full-fledged commercialization of PEFC requires cost down and its keyword is the development of novel perfluorinated ionomer material which enables the high performance and durability for fuel cell at higher temperature without humidification.
Platinum is used for the electrode materials of PEFCs. However, platinum is expensive and its resource is limited. Platinum is unstable in an acidic media and has not enough catalytic activity especially for oxygen reduction. Platinum is also not environmentally friendly, since it consumes huge energy to produce platinum metal. A development of a new catalyst without a platinum group metal is very important for the large distribution of fuel cells. Group 4 and 5 metal oxide-based materials might be good candidates for the new cathode material of a PEFC, since they have high stability in an acid media and relatively high catalytic activity for oxygen reduction.
Recently non-conventional fossil fuels including shale gas, oil sand and brown coal are considered as next generation resources for energy and chemical feedstock. In this report, recent trends about non-conventional fossil fuel and its utilization are summarized. Japan has only few options considering the situation.