A combination of two ordinary materials –
graphite and water – could produce energy storage systems that perform on par
with lithium ion batteries, but recharge in a matter of seconds and have an
almost indefinite lifespan.
Dr. Dan
Li, of the Monash University Department of Materials Engineering, and his
research team have been working with a material called graphene, which could
form the basis of the next generation of ultrafast energy storage systems.
“Once
we can properly manipulate this material, your iPhone, for example, could
charge in a few seconds, or possibly faster.” said Dr. Li.
Graphene
is the result of breaking down graphite, a cheap, readily available material
commonly used in pencils, into layers one atom thick. In this form, it has
remarkable properties.
Graphene
is strong, chemically stable, an excellent conductor of electricity and,
importantly, has an extremely high surface area.
Dr. Li
said these qualities make graphene highly suitable for energy storage
applications.
“The
reason graphene isn’t being used everywhere is that these very thin sheets,
when stacked into a usable macrostructure, immediately bond together, reforming
graphite. When graphene restacks, most of the surface area is lost and it
doesn’t behave like graphene anymore.”
Now,
Dr. Li and his team have discovered the key to maintaining the remarkable
properties of separate graphene sheets: water. Keeping graphene moist – in gel
form – provides repulsive forces between the sheets and prevents re-stacking,
making it ready for real-world application.
“The
technique is very simple and can easily be scaled up. When we discovered it, we
thought it was unbelievable. We’re taking two basic, inexpensive materials –
water and graphite – and
making this new nanomaterial with amazing properties,” said Dr. Li.
When
used in energy devices, graphene gel significantly outperforms current
carbon-based technology, both in terms of the amount of charge stored and how
fast the charges can be delivered.
Dr. Li
said the benefits of developing this new nanotechnology extend beyond consumer
electronics.
“High-speed,
reliable and cost-effective energy
storage systems are critical for the future viability of electricity
from renewable resources. These systems are also the key to large-scale
adoption of electrical vehicles.
“Graphene
gel is also showing promise for use in water purification membranes, biomedical
devices and sensors.”
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