It has yet to be commercialised, but graphene is a substance that promises to supercharge the field of energy storage. Graphene is a non-toxic, organic substance made purely of carbon (it can actually be composted) that is being investigated by researchers at the University of California Los Angeles (UCLA). While separate group of scientists won a Nobel Prize for discovering graphene in 2010, the UCLA team stumbled across its impressive energy storage qualities and has been working on a way to produce it on a mass scale.
Graphene is composed entirely of carbon atoms forming a ‘honeycomb lattice’ 1 atom thick. It is one of the strongest materials in the world for its relative lack of substance, but the most important (and ‘accidental’) discovery made by the UCLA team is its ability to store and release electricity. Graphene could be used as the basic component in a supercapacitor.
A capacitor is similar to a battery in terms of function–both hold and release electricity. Chemical batteries, whilst having higher energy storage potential than capacitors, have a number of disadvantages. The fact that they contain dangerous heavy metals and need to be properly disposed of and recycled after they’ve been used is a big weakness. They also take a relatively long time to charge up, and their storage potential can be permanently inhibited by too much deep discharging. Capacitors, on the other hand, are not as toxic and are good for quick charging and discharging; Where they fall down is their small amount of storage capacity.
A supercapacitor using a substance like graphene as its base would the best of both worlds. Like capacitors, supercapacitors charge and discharge much faster than chemical batteries, but they also have exceptional storage capacity. In a demonstration by the UCLA research team, a small piece of graphene charged for just a few seconds held enough electricity to power a small lightbulb for around 5 minutes. Seeing this for the first time, says Professor Richard Kaner, was the ‘aha’ moment that the research team was on to something huge. “I thought we had something very important. I thought the world changed at that point.”
Professor Kaner and PhD candidate Maher El-Kady have improved upon the technique that the graphene-discovering Nobel Laureates used to create the material. Instead of using ground up graphite and cellophane tape, the UCLA team deposits a liquid solution containing the graphite onto plastic (CDs) and bombards it with light from lasers (in a DVD burner). This seemingly simple process yields thin sheets of graphene with all the properties mentioned above.
An energy storage application for graphene has massive potential to change the future of energy if it can be produced affordably. A substance like graphene promises to change not only the future of batteries of all sizes, it also the investment game for for most types of renewable energy, for which lack of storage capacity (the ‘intermittency’ issue) is often seen as a problem when compared to conventional fossil fuel-based generation systems such as coal and gas plants.
Below is a short video featuring the UCLA team talking about their work and graphene’s energy storage potential.
Top image by AlexanderAlUS, via Wikipedia
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