**5.2 Fuel cells**

Alcohol fuel cell is an energy conversion device to generate electricity via electrochemical reactions on the catalytically active electrodes without direct combustion of alcohol fuel. Direct alcohol fuel cell (DAFC) is named for its direct supply of alcohol to fuel electrode and is called with specific terminologies as direct methanol fuel cell or direct ethanol fuel cell depending on the alcohol fuel source.

The mechanism of electricity generation is based on the oxidation of methanol fuel at the anode (fuel electrode) and conduction of electron(s) to the cathode (air or oxygen electrode) via external conducting circuit and simultaneous electrolytic conduction of proton (H+ ) via polymer electrolyte to the cathode.

DAFC can provide portable energy source to electronic devices such as cellular phones and notebook computers [23]. DAFC that uses alcohol can have several

**Figure 10.**

*Changing trend of automobile fuel in Brazil [22].*

advantages in terms of storage, transportation, safety, etc. over fuel cell systems like proton exchange membrane fuel cell (PEMFC) that use hydrogen.
