Next-Generation Fuel Cells


The worldwide market for portable fuel cells in 2008 was $80.1 million, and is expected to reach $4.4 billion by 2015. Similar to a battery, fuel cells are power generation devices that directly convert chemical energy into electricity. While a battery's active "fuel" is contained within, and must be disposed of or recharged after use, a fuel cell is supplied by an external fuel source - as long as there is fuel available, the fuel cell can operate for extended durations.

Fuel cells have the potential to serve a wide range of applications, including portable, stationary, and transportation power. Of particular interest is the portable power sector for commercial applications such as portable electronics and military applications such as unmanned systems. As these applications increase in capability, power consumption increases and device operating time decreases. Since a fuel cell power source can provide extended operating time or instant recharge, it is an excellent candidate for use in high performance electronics.

Portable fuel cells typically use hydrogen or methanol as a fuel source. Direct methanol fuel cells (DMFCs) are attractive because the fuel can be stored as a liquid, whereas hydrogen fuel would need to be stored as a compressed gas or in the solid state as a hydride for a hydrogen fuel cell. Furthermore, the theoretical energy density of methanol fuel (~ 6100 Wh/kg, 4800 Wh/L) is considerably higher than pressurized hydrogen (~ 1000 Wh/kg, 3000 Wh/L).

A direct methanol fuel cell is composed of an anode electrode, a membrane, and a cathode electrode that are sandwiched together to form a membrane-electrode assembly (MEA). The electrodes are typically made of platinum on carbon catalyst, and the membrane is an ion conducting polymer.


Despite their promise, DMFC's have been held back by multiple challenges. First, the theoretical energy density advantage of methanol fuel shown above is presently limited as methanol fuel degrades the performance of the membrane and catalysts used in a DMFC. To date, only very dilute solutions of methanol in water are used as the DMFC fuel source. Using dilute methanol adds both weight and volume to the fuel cell, which is less than desirable for portability. Next, most DMFCs are active systems - they require pumps and other peripherals to perform well. This also adds both complexity and size. Finally, the most common catalyst used in DMFCs is platinum, a precious metal that is expensive and limited in supply. Approximately 20 - 30% of a DMFCs cost is related to high platinum loading.

Ideally, a direct methanol fuel cell should be able to operate at high fuel concentrations, be simple and passive to operate, and use lower cost catalysts.


Through extensive catalyst development and use of superior membrane materials, QuantumSphere has developed MEA technology that allows the direct methanol fuel cell to operate with up to 10X higher methanol fuel concentrations, without a sacrifice in power, which can directly lead to as much as a ten times reduction in size and weight of the fuel tank. QSI's catalyst solution uses lower cost metals, engineered at the nano scale, to replace platinum. Palladium is one example, as it resembles platinum chemically, is extracted from copper-nickel ore, and is already used as a catalyst material in the catalytic converters of automobiles. It is 75% less expensive than platinum, and when used at the nano scale in direct methanol fuel cells, palladium has demonstrated an increased power density of 45%. This power enhancement is due to the unique physical characteristics and improved selectivity of the palladium catalyst; the morphology, purity, and additional surface area of QSI's nano scale materials play a major role. Using QSIs MEAs for DMFCs, these features translate to a dramatic efficiency improvement in the catalytic reaction, with a corresponding two to three times higher power out, and a thirty percent cost reduction for the catalysts. Thus, QSI's nano scale palladium catalysts and MEA designs are less expensive and lead to better performance at the same time.