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Cell Block H+
Battery technology has advanced considerably in recent years, with new designs and formulations improving power output and reducing size. But today's technologies may not be able to keep up with the demands placed on them by power-hungry technology. Processors, memory and graphics cards are always advancing, requiring more portable power to keep them running when away from the mains.
Happily, though, things are starting to change. New battery technologies and new power generators, in the form of fuel cells, are changing the mobile equipment landscape and promise good things for the future, and in some cases the near future.
Think of a power source that could run your notebook for eight hours straight and that would require you only to plug in another canister of fuel to give you a further eight hours. One with no recharge time, no slow discharge when your notebook is switched off and a weight reduction over your current lithium-ion battery pack. This is what fuel cells could offer. They aren't the only alternative to conventional batteries, though. In this article, we take a look at some of the other developments that could make life away from the wall socket easier.
FUEL CELLS
A fuel cell is like a battery in that it converts energy stored in chemical form into electricity, which can potentially be used to power anything from a mobile phone to an electric bus. Unlike a rechargeable battery, fuel cells are not recharged by connecting them to a power source. Instead, you need to add more chemical fuel to keep the process going.
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HYDROGEN FUEL CELL
There are two types of fuel cell, the simplest of which is a straight hydrogen-oxygen cell. In this type, the two gases are piped to the electrodes of the cell, where they combine forming water, freeing electrons in the process. These electrons form the current that drives the electrical equipment connected to the cell. The chemical reactions in a fuel cell are hydrogen gas breaking down into hydrogen ions and free electrons:
H2 => 2H+ + 2e-
and oxygen recombining with the hydrogen ions to form water:
O2 + 4H+ + 4e- => 2H2O
This means that the only by-product from a hydrogen fuel cell is water.
The snag with this type of cell is that you have to use free hydrogen, a highly flammable gas that is hard to distribute and bulky to store. Although it's not as dangerous as suggested by the tragedy of the Hindenburg airship, it still needs more careful handling than conventional petrol or diesel. Hydrogen fuel cells are under development for vehicles such as buses and cars and possibly for powering buildings, where a supply of hydrogen could be piped in, in much the same way as gas is for heating and cooking.
To make a fuel cell practical for smaller devices such as notebooks or PDAs, another approach is needed. Rather than using neat hydrogen, a different design of fuel cell is used, running on alcohol, most commonly methanol. The advantages are that methanol is a liquid, which is easily packaged and transported, and it can be easily derived from several different sources, including ecologically sound crops.
Unfortunately, the methanol fuel cell reaction isn't as energy dense as the one with neat hydrogen and it doesn't run as efficiently. Another disadvantage of a Direct Methanol Fuel Cell (DMFC) is that the overall reaction of the cell produces CO2 as well as water.
