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Recharge in seconds and efficiently store power for weeks between charges. Added bonus is the cheap and abundant components needed. One of the applications they foresee is to attach such a super-capacitor to the back of solar panels to store the power and discharge this during the night

very nice indeed - is this already at a stage where we should have a closer look at it? what you think? With experience in growing carbon nanostructures, Pint's group decided to try to coat the porous silicon surface with carbon. "We had no idea what would happen," said Pint. "Typically, researchers grow graphene from silicon-carbide materials at temperatures in excess of 1400 degrees Celsius. But at lower temperatures - 600 to 700 degrees Celsius - we certainly didn't expect graphene-like material growth." When the researchers pulled the porous silicon out of the furnace, they found that it had turned from orange to purple or black. When they inspected it under a powerful scanning electron microscope they found that it looked nearly identical to the original material but it was coated by a layer of graphene a few nanometers thick. When the researchers tested the coated material they found that it had chemically stabilized the silicon surface. When they used it to make supercapacitors, they found that the graphene coating improved energy densities by over two orders of magnitude compared to those made from uncoated porous silicon and significantly better than commercial supercapacitors. Transmission electron microscope image of the surface of porous silicon coated with graphene. The coating consists of a thin layer of 5-10 layers of graphene which filled pores with diameters less than 2-3 nanometers and so did not alter the nanoscale architecture of the underlying silicon. (Cary Pint / Vanderbilt) The graphene layer acts as an atomically thin protective coating. Pint and his group argue that this approach isn't limited to graphene. "The ability to engineer surfaces with atomically thin layers of materials combined with the control achieved in designing porous materials opens opportunities for a number of different applications beyond energy storage," he said.

Stacking laser printed supercapacitors (no clean room required btw) has lead to about 1100F/g and thus about 20-40Wh/L. For supercapacitors thats pretty damn good. For reference, Li-ion recently reached 650Wh/L. The gap is closing, although for supercaps of this type the theoretical maximum is 1400F/g.

is this the breaktrough that we were waiting for?

That depends on what application you are thinking of. For circuit board electronics this will allow integration of micro sized supercapacitors to provide operational power. They will have to be fed by external batteries still, but the close proximity allows for better tailored power demands. They also propose tapping into thermal/mechanical energy to charge the supercaps. In the end, they can provide significant specific power (W/kg) but you still need to upscale the production to cover large areas to also gain high specific energy (Wh/kg). This breakthough is for micro sized applications, not for replacement of large scale energy storage (electric vehicles, satellites) going up to kWh. That said, I know of several studies in supercaps at ESA, but they are still qualifying current relatively old commercial solutions.

"Her goal was to design and synthesise a super capacitor with increased energy density while maintaining power density and long cycle life. She designed, synthesised and characterised a novel core-shell nanorod electrode with hydrogemated TiO2(H-TiO2) core and polyaniline shell. H-TiO2 acts as the double layer electrostatic core. Good conductivity of H-TiO2 combined with the high pseudo capacitance of polyaniline results in significantly higher overall capacitance and energy density while retaining good power density and cycle life. This new electrode was fabricated into a flexible solid-state device to light an LED to test it in a practical application. Khare then evaluated the structural and electrochemical properties of the new electrode. It demonstrated high capacitance of 203.3 mF/cm2 (238.5 F/g) compared to the next best alternative super capacitor in previous research of 80 F/g, due to the design of the core-shell structure. This resulted in excellent energy density of 20.1 Wh/kg, comparable to batteries, while maintaining a high power density of 20540 W/kg. It also demonstrated a much higher cycle life compared to batteries, with a low 32.5% capacitance loss over 10,000 cycles at a high scan rate of 200 mV/s."

Known technically as a surface plasmon polariton (SPP) wave, the effect will allow the nano-antennas to operate at the low end of the terahertz frequency range, between 0.1 and 10 terahertz - instead of at 150 terahertz With this antenna, we can cut the frequency by two orders of magnitude and cut the power needs by four orders of magnitude," said Jornet. "Using this antenna, we believe the energy-harvesting techniques developed by Dr. Wang would give us enough power to create a communications link between nanomachines." As always, graphene seems to be the answer to anything, but steady progress is being made although one needs to find out first an easy method of generating high quality graphene layers (btw that is also one of the reasons to do the supercapacitor study...)

Well plasmonics is also the solution to everything it seems...