Turn on a flashlight and you're witnessing a fuel cell at work. At its most basic, a fuel cell is a power source that uses a chemical reaction to produce an electrical current. The battery inside the flashlight is a fuel cell that confines its chemicals into a tidy little package. Once the chemicals wear out and can no longer react with each other, the battery can be recharged or thrown away.
There is another type of fuel cell that relies on the intake of external elements. Instead of having all its elements enclosed, a hydrogen fuel cell, for example, needs access to peripheral elements like hydrogen and oxygen to produce electricity [source: CAFCP]. And this is where nanotechnology comes into play. The application of nanotechnology could make hydrogen fuel cells work more efficiently and make them less expensive to produce; this could result in lower prices for vehicles fueled by this type of alternative energy, as well as the production of fuel cells that require less energy to operate.
With nanocrystals in play, fuel cell manufacturing costs could also drop. Traditionally, hydrogen fuel cells use platinum as a catalyst to convert external elements into energy. Platinum is relatively rare and extracted through energy-intensive mining. By using platinum nanocrystals, it greatly reduces the amount of pricey platinum needed to make a fuel cell work. In some cases, nanocrystals of less-expensive materials like cobalt can be used to bypass the need for platinum altogether [source: Understanding Nano].
Nanocrystals could change the material used to construct fuel cells, too. Most fuel cells use liquid to connect electrodes because liquid is a better conductor than a solid material. But by infusing solid materials with nanocrystals, the materials themselves become more conducive, eliminating the need for a liquid conductor, which leads to saved space, increased conductivity and smaller fuel cells [source: Science Daily]. In the end, technology using some of the world's smallest particles could lead to the next big fuel source -- or at least a more efficient way to use the fuel sources we already have.