Direct Methanol Fuel Cell (DMFC)

Direct Methanol Fuel Cell (DMFC) is a fuel cell that runs directly on methanol (or various liquid fuels) without having to first convert those fuels into hydrogen gas. It consists of two electrodes separated by a proton exchange membrane (PEM) and connected via an external circuit that allows the conversion of free energy from the chemical reaction of methanol with air or oxygen to be directly converted into electrical energy. DMFC Diagram And it operates at cold temperature, creating little heat with some machines operating around 70°c or 158°f. Hydrogen fuel cells that operate on methanol use a separate reformer to release the hydrogen from the liquid methanol, then the hydrogen is fed into the fuel cell. DMFCs do it directly in the stack.
Reaction Formula is CH₃OH + 1.5O₂ --> CO₂ + 2H₂0
Cathode reaction is 1.5O₂ + 6H⁺ + 6e^- --> 3H2O
Anode reaction is CH₃OH + H₂O --> CO₂ + 6H⁺ + 6e^-

History

In 1990 Dr. Surya Prakash a world-renowned super acid specialist and Nobel laureate Dr. George A. Olah, both of the University of Southern California's Loker Hydrocarbon Institute invented a fuel cell that would directly convert methanol to electricity, H20 and CO2. USC, in a collaborative effort with Jet Propulsion Laboratory (JPL) proceeded to invent the direct oxidation of liquid hydrocarbons subsequently coined as DMFC, Direct Methanol Fuel Cell Technology. Others were involved in the invention, including California Institute of Technology (Caltech) and DTI Energy, Inc.
Advances in DMFC have been in bring down the fuel crossover (when the methanol molecule passes through the membrane),oxidation reduction, ruthenium crossover and hydrophobicity loss of cathode.

Many companies are developing DMFC machines

Toshiba; 2002 At world PC Expo demonstrated DMFC for Genio pda, 2009 Dynario is a external power source that delivers power to mobile digital consumer products, output 400 mA at 5 volts(2 watt) with limited sales (3,000)Medis Mass Production of Micro DMFC
Yahama; In 2003 built the first DMFC powered two-wheeler FC06 500 watt with a 300 watt power source for outdoor activities, leased scooters in 2006 FC-me and in 2007 FC-Dii with an optional high power 1000 watt cell.
Los Alamos National Labs & Motorola; 2001 Created DMFC fuel stacks with ceramic fuel plates.
Korea Institute of Energy Research; Made breakthroughs in pore size research
Daimler; 2005 tested a 3 wheel JuMOVe vehicle with a 1.3 kw DMFC and a go-cart 3.0 Kw DMFC
Oorja; 2008-2009 Installed 200 forklift DMFCs at Nissan and Safeway earlier ones were 500 watt to keep the electric forklift batteries charged later ones are 1500watt units and in 2010 they have released a 5000 watt DMFC for auxiliary power for trucks, RVs or marine applications, or for off-grid power for homes.
Vectrix; In 2003 built and tested a 800 watt DMFC to extend the distance on its electric motorcycles.
Smart Fuel Cell AG October 2008 Won the US military Wearable Power Competition. SFC took both first and third place, with the M-25 Portable Fuel Cell, which it co-developed with DuPont, taking first, and The Jenny coming in at No. 3. SFC sold over 16,000 commercial fuel cells from 1994 to early 2010.
Motorola In 2003 developed ceramic structure reducing size and cost into a miniature fuel cell.
Samsung Electronics 2009 military applications DFMC weighing 7.7lbs (3.5kg), giving 1,800 Watt-hours (max output ?)
NEC (Japan) 2004 Used electrodes made from a carbon nanotube called a nonohorn in a miniature DMFC.
Medis Technologies, Inc. In 2007, one of the first companies that produced and brought to market, in volume, a commercial Micro Fuel Cell DMFC product. Now defunct. See Video of Medis Fuel Cell Power Emergency Kit (5 volt, 220ma, 1watt)
Hitachi In 2003 created a prototype cartridge about the size of a AA battery that could power a PDA for six to eight hours.
Fraunhofer Institute for Solar Energy Systems
Neah Power Systems 2004 Changed the PEM polymer membranes to porous silicon layers. This may improve performance and ease manufacture.
Methanol CH₃OH is in liquid form on earth from -97.0 °C to 64.7 °C (all temperatures). When the energy density of methanol is compared to pressurized and frozen liquid hydrogen (LH₂) (the densest form of hydrogen) there is more hydrogen 98.8 grams per liter in methanol verses 70.8 grams per liter in LH₂. Hydrogen storage is expensive, bulky and will require an entirely new infrastructure while methanol is already used in ICE engines (as in: Indy 500 cars), converted to formaldehyde for plastics and Di-methyl ether (DME) (CH₃OCH₃). Methanol can use the existing petroleum infrastructure with little changes. When compared to superior battery technologies methanol's theoretical energy density is much better at around 5000 Watt hour/liter verses 1500 watt hours/liter for lithium batteries.
The reactions work like this, the anode is exposed to methanol/water mixture fed from an external container where its protons travel through the PEM by ionic conduction and the electrons travel through the external circuit by electronic conduction. The cathode containing platinum is exposed to oxygen in air which is pressurized or ambient. The PEM is coated on both sides with layers of catalyst. The cathode has a graphite electrode which facilitates reduction of oxygen and the anode has a liquid feed-type carbon electrode structure facilitates the necessary oxidation of methanol.