Kanagawa Accademy of Science and Technology
Yamaguchi “Next-generation High-efficiency Fuel Cells” Project
 Toward an energy friendly eco-society

Research Target

Under the current state-of-the-art technology, the efficiency for conversion from fossil fuels to work (electricity) remains low, less than half of the ideal conversion efficiencies based on thermodynamics. There is an increasingly urgent need to develop a society that can consume energy resources more carefully. Otherwise, we face the depletion of fossil fuels and the problems associated with global warming. In this regard, development of new power generation (fossil fuel to electricity) technologies is essential.
Project Leader: Dr. Takeo Yamaguchi ( Prof. of Tokyo Institute of Technology Chemical Resources Laboratory)
Investigation period: 2013-2017.

 Among the various fuel cells gaining prominence in recent years, polymer-electrolyte fuel cells (PEFCs) represent a superior system, exhibiting low-temperature operation, compact size, portability and high-efficiency generation on demand at desired levels. High-efficiency generation at low temperatures ranging from normal temperatures to around 100˚C requires the supply and adjustment of water content for the electrolytes, as PEFCs need proton transfer. But this behavior also impedes attainment of high efficiency and improved reliability. Another challenge is to reduce the amount of platinum usage before scaling up. Doubling and tripling the current power density can immediately reduce the entire fuel cell cost, in addition to the requisite amount of platinum.

 A revolutionary improvement in the electrolyte membrane or catalyst layer that enables operations over a range of low humidity to high humidity, and thus not only in  liquid water but in water vapor at 100˚C or higher, would achieve vastly improved efficiencies along with reliability and lower cost. Innovative ideas will also be able to solve fuel cell power density that is currently limited by mass transfer of the substances. The contemplated project consists of systematically designing and developing new materials, in order to bring the outstanding areas described to reality. Short-term development of a new membrane and catalyst is both an interesting and necessary material function, designed from the molecular level, where targeted functions embrace the device level.

  We will aim to achieve mitigation of humidity and temperature dependence on membrane performance, reduce the platinum content in catalyst through improved activation, and improve durability for membranes and catalyst. For this device, we shall promote mass transfer, high power and improved durability. Through these achievements, we can build a society that uses energy resources more carefully and does not depend on large power generation plants.

Project details

1.Development of novel catalysts and catalyst layer materials

A super lattice structure of multiple metal elements reduces expensive platinum content, and drives high performance and high durability in new catalyst development. Mass transfer of substances and catalyst-layer material development call for high performance achieved even under high-temperature, low-humidity environments. Coordination of the above achieves a low-cost, high-efficiency catalyst and catalyst layer.

Fig. 1 Catalyst and electrode materials

 

2.Development of electrolyte membranes for high-temperature and low-humidity conditions

We developed pore-filling electrolyte membranes by filling electrolyte polymer with porous substrate. Novel materials for porous membranes substrates and polymer electrolytes for the pore-filling membranes will be developed for high temperature and low humidity operation. The outstanding characteristics of pore-filling membrane technologies will be widely transferred to other energy devices.

Fig. 2 Pore-filling electrolyte membranes

3.Development of polymer electrolyte fuel cells (PEMFCs) with high power and efficiency under high-temperature and low-humidity conditions

The developed catalyst layer structure having fast mass transfer and high-temperature, low-humidity compatible materials are merged to fabricate a membrane electrode assembly, and fuel cell characteristics will be evaluated. Working through sophisticated simulation technologies, device designs of higher efficiency will be studied, and ultimately, development of next-generation high-efficiency fuel cells will be targeted through the achievement of high performance and high output at low cost under high-temperature, low-humidity environments.

Fig. 3 Membrane-electrode assembly (Fuel cell)