Stanford scientists make graphene-aluminum battery that charges quickly and lasts over 7,000 cycles

Researchers at Stanford University developed a new battery technology based on graphene and aluminum. The stanford team claims that their aluminum battery has a number of advantages over lithium: it's flexible, can be charged in a minute instead of hours and is very durable. it's also cheaper and non-reactive (meaning compromising it will not result in sparks like lithium batteries).

The scientists used graphene foam (made by creating a metal foam, then catalyzing graphene formation on its surface) as cathode material and aluminum foil as the anode. The electrolyte the researchers used was a solution of aluminum trichloride dissolved in an organic solvent that also contained chlorine. While this granted better performance (7,500 cycles, much more than the 1,000 expected from a Li-ion battery), the voltage provided by an aluminum-ion battery is only about half of that what you'd get from a lithium-ion cell. Also, the overall power density (the amount of power you can store in a battery in relation to its size) is still insufficient.

Read the full story Posted: Apr 08,2015

Researchers show that 3D materials that behave like graphene are possible

Researchers from Oxford, Stanford and the Lawrence Berkeley National Laboratory discovered a new 3D material (Na3Bi) that behaves like graphene. While it is very unstable, this is still a significant discovery as it shows that it's possible to find 3D materials that have similar properties to graphene.

The fact that graphene is a single sheet of atoms (a 2D material) makes it difficult to work with. A 3D material will be easier to handle, and this is why the researchers are excited about their discovery. The new material, a sodium-bismuth compound, is a three-dimensional topological Dirac semimetal - that has a unique behavior of its electrons (it's actually represents a new quantum state of matter).

Read the full story Posted: Jun 06,2014

Researchers understand why CaC6 (graphene-calcium) is superconductive

It's been long known that adding calcium atoms between graphene sheets can make it superconductive. Now researchers from the US DoE SLAC National Accelerator Laboratory and Stanford University showed for the first time graphene's role in the superconductivity of this materials (called CaC6).

The researchers used intense ultraviolet light beams to see the structure of the CaC6 material. Using the light one can see how electrons scatter back and forth between the graphene and the calcium, interact with natural vibration in the atomic structure of the CaC6, and pair up to conduct electricity without resistance.

Read the full story Posted: Mar 20,2014

Researchers manage to produce 2D MoSe2 sheets

Researchers from the SLAC lan in Stanford University developed a new method to make 2D material molybdenum diselenide or MoSe2 that has possible applications in photoelectronic devices, such as light detectors and solar cells, and perhaps also novel electronic devices.

This is the first time single-layer MoSe2 has been efficiently produced. The method they developed is based on molecular beam epitaxy, and starts with molybdenum and selenium, which are heated in a vacuum chamber until they evaporate. The two elements combined as a thin film. By tweaking the process, they managed to create thin films - one to eight atoms thick. Those sheets were grown on graphene substrates. 

Read the full story Posted: Jan 12,2014

A tin-based 2D material is a better conductor than graphene

Researchers from Stanford University and the SLAC National Accelerator Laboratory have discovered a new 2D material (which they call Stanene) that may conduct electricity better than graphene. Stanene is actually a topological insulator - and as such its edges conduct electricity with 100 percent efficiency.

Stanene is similar to graphene, but it is made from tin atoms. The researchers say it is the first material to conduct electricity with 100% efficiency at the temperatures that computer chips operate. Of course this is all currently just theoretical predictions, but hopefully soon experiments will confirm those predictions.

Read the full story Posted: Jan 09,2014

Stanford researchers use DNA to assemble graphene ribbons

Researchers from Stanford developed a new way to produce graphene ribbons using DNA strands. GNRs have a bandgap and so can be used as building blocks for transistors, and indeed the researchers produced transistors based on GNRs produced using this new process.

The process goes like this: it starts with a silicon substrate, dipped in a DNA solution (derived from bacteria). They then combed the DNA strands into relatively straight lines (using a common technique). They exposed the DNA to a copper salt solution which allowed the copper ions to be absorbed into the DNA.

Read the full story Posted: Sep 07,2013

Single-layer graphene is about 100 times more chemically reactive than double or triple sheets of graphene

Researchers from Stanford discovered that single-layer graphene is about 100 times more chemically reactive than double or triple sheets of graphene. The team bombarded single and multiple sheets of graphene (on silicon oxide substrates) with highly reactive hydrogen atoms generated in a stream of charged gas, or plasma. When they looked at the graphene afterwards, they found out that the single sheet of graphene was riddled with etch pits, but thicker layer were hardly pitted at all.

Those pits were caused by graphene's carbon atoms reacting with hydrogen atoms, presumably creating methane molecules that lift up and away out of the graphene sheet. The silicon oxide substrate is a participant in the etching reaction.

Read the full story Posted: Feb 01,2013

A solar cell made entirely from carbon, contains graphene electrodes

Researchers from Stanford University managed to build a solar cell made entirely from carbon. Solar panels made from such materials can provide high performance at a low cost. The entire panel can be built using a coating process (the materials are soluble) and can be made flexible.

The two electrodes in the device are made from graphene and single-walled carbon nanotubes. The active layer (sandwiched between the electrodes) is made from buckyballs (which can be used to create graphene quantum-dots, by the way).

Read the full story Posted: Nov 07,2012

Graphene turned piezoelectric by doping

Researchers from Stanford managed to engineer Piezoelectricity into graphene. Piezoelectricity is the property of some materials to produce electric charge when bent, squeezed or twisted. It is reversible - so you can change the materia's shape using an electric field.

A piezoelectric graphene could provide an unparalleled degree of electrical, optical or mechanical control for applications ranging from touchscreens to nanoscale transistors, said the researchers.

Read the full story Posted: Mar 18,2012