[TWIAR] ST Microelectronics article on cheaper batteries

[Greg Williams]

http://www.st.com/stonline/press/news/year2003/t1346h.htm

Micro Fuel Cells May Replace Batteries in Mobile Phones 

Geneva, September 10, 2003 - The need to regularly recharge batteries
in mobile phones, laptops and other portable terminals may be
eliminated in the future, according to the latest developments by
leading silicon chip manufacturer STMicroelectronics (NYSE: STM). ST,
which has long been one of the major suppliers of the silicon chips
used in mobile phones, has reported progress by one of its advanced
R&D teams in developing tiny fuel cells, small enough to fit inside a
mobile handset, that could generate all the electrical energy needed
to power the phone from cheap and easily available organic fuels.
A fuel cell is a device that generates energy using electrochemical
reactions instead of fuel combustion. In recent years, there has been
enormous interest in fuel cells because they promise to deliver
cheap, clean energy. Although much of the work in the emerging field
of fuel cell technology has been aimed at automotive applications, ST
researchers have also been investigating the replacement of the
rechargeable batteries used in mobile phones by tiny fuel cells that
can be refilled with fuel whenever needed, just like refillable
cigarette lighters.

"Using fuel cells instead of batteries would make mobile phones
lighter and much more convenient to use as they could be simply
topped up with fuel whenever necessary. In addition, there would be
significant environmental benefits as the fuel can be derived from
sustainable organic sources, while the by-products are mainly water
and a much lower level of carbon dioxide than is produced by burning
fossil fuels," says Dr. Salvo Coffa, who leads the Corporate
Technology R&D team that is researching the micro fuel cell
technology.

The operation of a fuel cell involves the chemical interaction
between hydrogen and oxygen to produce water, heat and electrical
energy. Typically, a fuel cell consists of a pair of electrodes (the
'anode' and the 'cathode') separated by a membrane that allows
protons (hydrogen ions) to pass through the membrane but does not
allow an electric current to pass. In addition, catalysts such as
platinum are used to increase the rate of the reaction and therefore
the amount of electrical energy produced.

The main problem with applying fuel cell concepts to mobile phones is
that the power source (battery or fuel cell) must be able to deliver
around 300mA of current at 3.6V and it must not occupy a volume of
more than around 12 cubic centimeters. However, the output current of
a fuel cell is directly related to the common surface area between
the electrodes and the membrane and to obtain 300mA of current using
conventional fuel cell technologies would require a surface area of
around 60 square centimeters, much larger than is available in a
mobile phone.

ST has made important progress in overcoming this problem by
developing new technologies in which the fuel cell could be
implemented as a 3D structure containing thousands of buried
microchannels that maximize the contact area between the gases, the
catalysts and the electrodes.

The ST research team has also succeeded in fabricating a special
nanoporous layer, consisting of a layer of silicon containing
millions of pores, each measuring just a few nanometers in diameter.
The small pore sizes give the layer a very large effective surface
area, thus increasing the efficiency of the catalysis. In addition,
the ST team is working with the University of Naples to develop novel
membranes that exhibit high proton conductivity and lower cost
compared to the membrane materials that are commercially available
today.

"ST is committed to researching new technologies that could help to
minimize the impact of industrial and consumer products on the global
environment. Although there is still further work to do before these
developments can be integrated into a commercial technology, we are
very excited about their potential," says Coffa.

The ST work on micro fuel cells is partially supported by a National
Research Project, aimed at developing small fuel cells for portable
electronic applications, in which several other Italian institutions
participate (CNR-IMM, CNR-ITAE, CNR-ITS and Pirelli labs). In the
project, ST leads and coordinates the activity related to micro-fuel
cell fabrication and integration.


About STMicroelectronics
STMicroelectronics, one of the world's three largest independent
semiconductor suppliers, is a global leader in developing and
delivering semiconductor solutions across the spectrum of
microelectronics applications. An unrivalled combination of silicon
and system expertise, manufacturing strength, Intellectual Property
(IP) portfolio and strategic partners positions the Company at the
forefront of System-on-Chip (SoC) technology and its products play a
key role in enabling today's convergence markets. The Company's
shares are traded on the New York Stock Exchange, on Euronext Paris
and on the Milan Stock Exchange. In 2002, the Company's net revenues
were $6.32 billion and net earnings were $429.4 million. Further
information on ST can be found at http://www.st.com.

Technical Appendix 
What Is A Fuel Cell?

In principle, a fuel cell operates like a battery. Unlike a battery,
a fuel cell does not run down or require recharging. It will produce
energy in the form of electricity and heat as long as fuel is
supplied.

A fuel cell consists of two electrodes sandwiched around an
electrolyte. Oxygen passes over one electrode and hydrogen over the
other, generating electricity, water and heat.

Hydrogen fuel is fed into the 'anode' of the fuel cell. Oxygen (or
air) enters the fuel cell through the cathode. Encouraged by a
catalyst, the hydrogen atom splits into a proton and an electron,
which take different paths to the cathode. The proton passes through
the electrolyte. The electrons create a separate current that can be
utilized before they return to the cathode, to be reunited with the
hydrogen and oxygen to form a molecule of water.

A fuel cell system which includes a 'fuel reformer' can utilize the
hydrogen from any hydrocarbon fuel - from natural gas to methanol,
and even gasoline. Since the fuel cell relies on chemistry and not
combustion, emissions from this type of a system would still be much
smaller than emissions from the cleanest fuel combustion processes.

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