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GENERAL INTEREST
56 Elektor Electronics 11/2002
Motorola researchers have further integrated
the fuel cell processes. NEC researchers are
making use of the highly fashionable carbon
nanotubes. While those at Pennsylvania Uni-
versity have managed to make one run on
conventional diesel fuel — thus obviating the
need for ‘reforming’ fuels to hydrogen.
PEM cells
The fuelcells used by the Motorola and NEC
researchers are of the proton exchange or
polymer electrolyte membrane (PEM) type. A
porous carbon anode containing a platinum
catalyst splits the fuel into hydrogen protons
(ions) and electrons. The electrons pass
through an external electrical circuit, while
the protons pass through the humidified
membrane. The protons go to a cathode of
the same material as the anode, and there
recombine with the
returning electrons and with oxygen from the
air to form water. This is known collectively
as the membrane electrode assembly (MEA).
Researchers at Motorola Labs have now
demonstrated a prototype of an integrated,
miniature direct methanol fuel cell (DMFC)
system; and have also built several of the key
components required for a miniature, reformed
methanol to hydrogen fuel cell (RHFC).
Previous DMFC systems have used dis-
crete components to process and deliver
methanol to the fuel cell, to determine the
methanol concentration within the fuel cell,
and to separate the carbon dioxide gener-
Fuel Cell
Developments
further outlook: colder
By Reg Miles
Although fuel cells are still largely the stuff of the future, some recent
developments look set to bring that rather closer and give a good idea of
the way research is going.
Figure 1. Motorola’s experimental reformed methanol to hydogen fuel cell
(RHFC).