Harvesting energy from thin air
Researchers at Manchester University in the UK say their latest discovery involving graphene could be the most revolutionary advance in battery technology yet. Graphene membranes could be used to sieve hydrogen gas from the atmosphere, a development that could pave the way for electric generators powered by air.
"It looks extremely simple and equally promising," said Dr Sheng Hu, post-doctoral researcher in the project. "Because graphene can be produced these days in square metre sheets, we hope that it will find its way to commercial fuel cells sooner rather than later."
The essence of the technology is the remarkable physical properties of graphene. Isolated in 2004 by a team from Manchester University headed by Andrew Geim and Kostya Novoselov, both of whom won the Nobel Prize for Physics for their discovery in 2010, graphene is already well known as a groundbreaking technology.
The first two-dimensional crystal known to science, graphene is the thinnest, lightest and strongest object ever obtained. It is harder than diamond and 200 times stronger than steel. Flexible, transparent and able to conduct electricity even better than copper, the ground-breaking substance is set to revolutionize everything from smartphones and wearable technology to green technology and medicine.
The latest discovery makes graphene attractive for possible uses in proton-conducting membranes which are at the core of modern fuel-cell technology. Fuel cells work by using oxygen and hydrogen as a fuel, converting the chemical energy produced by its input directly into electricity. However, current membranes that separate the protons necessary for this process are relatively inefficient, allowing contamination in the fuel crossover. Using graphene membranes could boost their efficiency and durability. The team found the protons passed through the ultra-thin crystals with relative ease, especially at raised temperatures and with the use of a platinum-based catalyst coated on the membrane film.
The most surprising aspect of the research, however, found the membranes could be used to extract hydrogen from the atmosphere. The scientists said such harvesting could be combined with fuel cells to create a mobile electric generator fueled simply by hydrogen present in air. Currently, hydrogen is obtained nearly entirely from fossil fuels.
Already scientists are finding new ways of processing graphene and new applications for the invisible substance. Because it is flexible and stretchable, it makes it an ideal candidate for solar generation. Although the application of graphene in solar cells is only theoretical, the potential could be staggering. Solar cells made with graphene could offer 60% solar cell efficiency - double the widely-regarded maximum efficiency of silicon cells.
Apart from uses in transportation, where its lightness and strength stands to transform the manufacture of cars and planes to make them more fuel efficient, graphene has been studied as a corrosion-proof coating for packaging and even super-thin condoms.
In medicine, researchers say it could be used to deliver drugs to specific sites in the body and is being developed as a treatment for people with brain conditions.
In industry, its use as a membrane is being studied as a means of purifying water and even as a way of extracting salt and other elements from sea water to make it drinkable.