Description: Polymer electrolyte membrane water electrolysis units are currently designed to require active water flow and phase separation, or are based on a passive vapor transport mechanism that inherently limits performance due to mass-transport limitations. ElectroChem has developed and successfully demonstrated a passive water transport Integrated Flow Field concept (its IFF Structure) that controls the flow of water through each cell, in a highly reliable, performance enhancing, and gravity independent manner. By enabling the passive transport of liquid water to and from the membrane, it simplifies the structure of the electrolyzer system while avoiding performance limits due to mass transfer problems that have plagued conventional electrolyzers. ElectroChem will develop a high performance electrolysis unit that is based on the passive transport of liquid water into, within, and out of the cell. A custom-designed IFF cell structure will be developed during Phase I to refine approaches to optimized performance under a wide range of conditions, including gravity independence, higher current, and prolonged-period stable operation. The Phase II program will focus on multi-cell stack development and higher pressure modifications in support of energy storage systems free of mechanical compressors and water circulation pumps.

Benefits: The production of hydrogen to support mass-produced fuel cell vehicles remains a major "infrastructure challenge", but it can be directly addressed by the electrolysis of hydrogen at home using off-peak electricity. The passive liquid feed electrolyzer design has the potential to manufacture such a commercial unit at the lowest possible cost and highest reliability due to its simplified operation and high power-density design. By addressing the refueling issue "one-car-at-a-time", the potential market for such a system would be a major fraction of all hydrogen vehicle sales. Additional market potential exists in energy storage systems for extended capacity backup power units. Such regenerative power systems would provide backup power (longer than 3 hours) to critical systems such a cell phone towers and internet based network servers for critical computer systems.

Extended missions to the Lunar and Martian surface depend upon the efficient storage of energy for use during long nighttime periods. Highly reliable and efficient systems based on passive feed electrolysis will provide a compact and low maintenance capability to store electrical energy as compressed hydrogen and oxygen gas produced from water. The high energy density systems have the potential to produce these gases at high pressures, without external compression.