The direct methanol fuel cell (DMFC) is a relatively recent addition to the suite of fuel cell technologies; it was invented and developed in the 1990s by researchers at several institutions in the United States, including NASA and the Jet Propulsion Laboratory. It is similar to the PEM cell in that it uses a polymer membrane as an electrolyte. However, the platinum-ruthenium catalyst on the DMFC anode is able to draw the hydrogen from liquid methanol, eliminating the need for a fuel reformer. Therefore pure methanol can be used as fuel, hence the name.
Methanol offers several advantages as a fuel. It is inexpensive but has a relatively high energy density and can be easily transported and stored. It can be supplied to the fuel cell unit from a liquid reservoir which can be kept topped up, or in cartridges which can be quickly changed out when spent.
DMFCs operate in the temperature range from 60ºC to 130ºC and tend to be used in applications with modest power requirements, such as mobile electronic devices or chargers and portable power packs. One particular application for DMFCs which is seeing commercial traction in various countries is the use of DMFC power units for materials handling vehicles. A number of these units have been sold to commercial warehouses, where the forklift trucks had been conventionally powered with battery packs. By switching to fuel cells, the warehouses can refuel their trucks in a matter of minutes, compared to the hours it would take to charge a battery. The fuel cells also eliminate the need for a battery charging infrastructure within the warehouse, thereby making more floor space available for other uses.
Other types of fuel cell technologies available: