Graphene sheets. Image: Gengping Jiang |
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,” says 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.
Li says 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, 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,” says 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.
Li says 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.”
Li has been working with graphene since 2006 and his team’s research
findings have recently been published in a number of journals including Advanced Materials, Angewandte Chemie, and Chemical
Communications.
