Technology

Limitless energy and the graphene revolution

 By Chris Dalby

The coming of graphene has been heralded as a modern-day miracle. Virtually every industry has awaited the benefits of this sheet of carbon just one atom thick, so thin as to be seen as two-dimensional. Since being discovered in 2004, it has been called “300 times stronger than steel, thinner than a sheet of paper, and more conductive than copper…”

So where are the benefits? Has the revolution been muted somehow?
Not exactly. While graphene has not blown away the energy industry with one specific technology, the progress has been constant and important.

Graphene solar cell

Two years ago, a new lithium-ion battery was unveiled. Containing graphene polymers, it had a recharge speed 33 times faster than the competition. Then, earlier this year, a new solar cell was released, combining organic materials with graphene electrodes. The graphene made them more resistant, less prone to decay and increased optical transmittance.
This solar cell would essentially be made of an ideal synthesis of low-cost organic materials and graphene electrodes, to provide a flexible material from which to build transparent cells. At the core of this technology is a new method, pioneered by MIT, of placing a layer of graphene, no more than an atom thick, on top of the solar cell.
The transparency of the cells is particularly attractive as it would allow the cells to be placed on virtually any surface, including windows and walls, cell phones, laptops, even perhaps roads, despite an already inconclusive attempt at the latter.
The solar industry has faced a challenge in developing transparent cells as they have relied on expensive, fragile electrodes that often broke or cracked when applied or bent.

A flexible graphene solar cell developed at MIT is seen in the transparent region at the center of this sample (Stuart Darsch)

The mixture of organic compounds, containing carbon, also are likely to outpace inorganic, silicon-based cells. Being cheaper and easier to manufacture and transport, they would be far more suited to being deployed in remote regions.
MIT also indicates that its transparent, organic cells would better absorb the ultraviolet and infrared components of sunlight.
While such organic, transparent cells have been the focus of research for over a decade, the right materials for the electrodes were a stumbling block.
“It’s rare to find materials in nature that are both electrically conductive and optically transparent,” says Professor Jing Kong of MIT’s Department of Electrical Engineering and Computer Science (EECS).
Graphene has largely seemed to solve this conundrum. But while the energy applications of graphene to date have not been particularly headline-grabbing, there is a new twist.

Graphene generator

The University of Arkansas has developed a tiny power generator made of graphene, which it says could provide “limitless energy.” The composition of graphene essentially allows this generator to continuously recharge itself. If commercialized, this will be an absolute lifesaver for batteries and power cells for everything from pacemakers to plants.
The university’s Professor Paul Thibado explains that this relies on yet another advantage of graphene, its nature as a 2D material allowing it to be used as a source of clean, limitless energy. While slightly awkwardly named the Vibration Energy Harvester (VEH), it uses the motion of graphene to self-generate electricity.
Thibado’s vision is an exciting one, as he says such generators would “transform our environment, allowing any object to send, receive, process and store information, powered only by room temperature heat.”

A Potential Source of Clean, Limitless Energy

The size of the graphene pieces Thibado is experimenting on would provide immense scaleability. Each one measures about ten microns across, “so tiny that more than 20,000 of them could fit on the head of a pin.” The University of Arkansas research team estimates each one could provide 10 picowatts of power, or enough for each membrane to power a wristwatch without ever running out of juice.
While wristwatches are an outdated analogy, Thibado thinks that biomedical sciences would be the immediate benefactors, as graphene generators could be used to power pacemakers, hearing aids and wearable sensors. “Self-powering enables smart bio-implants,” explained Thibado, “which would profoundly impact society.”

And more to come…

These examples are just two energy projects, among many with graphene at their core. Graphene nano-platelets are being studied for their energy storage potential. It is increasing the efficiency of supercapacitors.
The graphene revolution never died, it is simply taking its time.

READ MORE: Converting CO2 to rock by RP Siegel

about the author
Chris Dalby
Journalist. Editor. China, Mexico, Latin America, Asia, place branding, Olympics, oil and gas, mining, renewable energy, international politics.