Friday, November 20, 2009

Carbon: from hazard to hero

Carbon is the climate-killer element of the 21st century -- however, it's also a potential miracle material that could not only dramatically reduce our energy requirements but also revolutionise the way we build computers and other electronic devices.

While most of us are busy releasing billions of tonnes of climate-altering carbon into the atmosphere every year, there are some dedicated researchers who already claim that carbon will be the basis for a whole new generation of technologies that will significantly improve our lives.

One of the key new carbon-based materials is graphene, effectively a lattice of carbon just one molecule thick.

Graphene displays a wide number of very interesting physical and electrical properties that might represent the future of ultra-miniature hi-speed electronics and high capacity energy storage.

While researchers struggle to come up with more effective battery technologies, increasing attention is being paid to the use of graphene films to create "supercapacitors".

Unlike chemical batteries that store electricity by way of reversible chemical reactions, supercapacitors directly store the electrons that create the flow of electrical current.

In order to store enough electrons to rival the capacity of chemical batteries, a supercapacitor needs an enormous internal surface area on its plates. The thicker the plates, the less area can be crammed into a given volume and the heavier the capacitor will become. Existing capacitor technologies rely either on thin metal foil or film, often separated by an insulating sheet, liquid or even a simple oxide layer on one of those plates.

In such capacitors, the total storage ability is limited primarily by the thickness of the metal plates. By switching to graphene it is expected that the capacitance (therefore the number of electrons that can be stored in a given volume) will be increased by many orders of magnitude.

Within a decade or two, chemical batteries as we currently know them may have all but disappeared.

Some researchers suggest that in their place will be graphene-based supercapacitors delivering a far longer service life while allowing recharging in just seconds rather than hours. What's more, they'll be capable of delivering much higher peak currents, along with significantly higher energy densities.

The important bits of a modern hi-tech piece of consumer electronics such as a netbook computer are presently comprised largely of silicon and lithium. The netbook of the future could well be heavily based on carbon instead.

One thing is for sure with this new carbon technology -- it's unlikely we'll ever run out of the raw material and the more of it we can sequester into a new generation of electronic devices, the better off our climate will be.

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