Why energy storage is really superficial

If you want to improve the performance of batteries and capacitors, one sure-fire way is to increase charge density. And the way to do this is to up-scale the surface area of your electrodes. Various configurations of carbon, both alone and in combination with other elements, can provide that increase, which is why we have reported on everything from nanoflowers to a carbon nanofoam.

The latest news in the battle for increased surface area comes from Rice University, where scientists have seamlessly combined carbon nanotubes a few atoms wide and 120 microns long onto one-atom thick graphene sheets, reports Science Daily. That means that if the nanotubes were the same width as an average house, they would rise up from the graphene ‘ground’ like mega-skyscrapers… into space.

As you can imagine, that’s a lot of surface area: 2,000 square metres per gramme of material, in fact. But what about practical applications? Researchers at Rice say their tests indicate the material already performs as well as the best carbon super-capacitors.

Graphene research excites investor

Graphene is making an impact beyond the lab and into the boardroom, it seems. Graphite mining company Focus Graphite has reached an agreement to develop next-generation rechargeable batteries with Hydro-Quebec’s Reseach Institute, reports Proactive Investors UK.

The three-year research and development deal will actually be between the Institute and Focus’s privately-held joint venture Grafoid, with the eventual objective of producing rechargeable batteries based on graphene and lithium iron phosphate materials.

Scientists reveal lithium-ion secrets

Physicists at the US Department of Energy’s Brookhaven National Laboratory and collaborating institutions have developed methods of examining lithium-ion reactions in real-time to a nanoscale (billionths-of-a-metre) precision, offering unprecedented insights into processes that are vital to battery technology, reports NanoWerk.

“(L)ive, nanoscale imaging may help pave the way for developing longer-lasting, higher-capacity lithium-ion batteries. That means better consumer electronics and the potential for large-scale, emission-free energy storage,” commented Feng Wang, one of the key researchers on the project.

New solar storage possibilities from MIT

Scientists at the prestigious Massachusetts Institute of Technology (MIT) have produced modified carbon nanotubes that can store solar energy indefinitely after being charged up by sunlight, says the university.

Although nano materials that store sunlight in chemical bonds have been produced before, researchers on this project say that the new material, which is made using carbon nanotubes in combination with a compound called azobenzene, has a much higher energy density than earlier solutions. In fact the energy density of this solutions is comparable to that of lithium-ion batteries.

Bike powered storage wins design prize

South Africa-based Ideso has won a prestigious international design award for its PowerPac generation and energy storage unit. Retailing at around USD$668, PowerPac attaches to a common-or-garden bicycle to utilise peddle power and can store up to 132Wh of electricity for home use, reports Media Club South Africa.

Electric car batteries enjoy life after death

They may add thousands of dollars to the purchase price of the vehicle itself, but now it looks like used Chevrolet Volt batteries will extend their usefulness in the greening of society beyond their use on the road.

ABB and GM have announced that the lithium-ion packs that power the Chevy Volt have been successfully re-used in a prototype unit that provides 25kW of power and 50kWh of energy for the home, enough to electrify three to five average US homes for two hours, say ABB.

The back-up energy storage unit repackages five used batteries, thus considerably extending their total useful lives and, perhaps, making the initial high cost of the batteries a more attractive initial investment.

Researchers trust rust for energy storage

An integrated solar cell that produces hydrogen as a form of energy storage is being investigated by researchers at the Ecole Polytechnique Fédérale de Lausanne (EPFL), in Switzerland. Converting solar to hydrogen is hardly a new idea, but so far solutions to the problem have been very costly. The EPFL system sidesteps this problem by using iron oxide, better known as rust, and water.

Of course, this is not common-or-garden rust but ‘nanostructured rust’: enhanced with silicon oxide and covered with a nanometer-thin layer of aluminum oxide and cobalt oxide. But it is still cheap to produce, say scientists at EPFL. The one drawback is low efficiency. At 1.4% to 3.6%, the prototype is not going into production anytime soon.

However, researchers are confident they can attain efficiencies of 10% in a few years, for less than USD$80 per square metre.