Graphene supercapacitor breaks storage record
December 10, 2010 // Julien Happich
Researchers in the US have made a graphene-based supercapacitor that can store as much energy per unit mass as nickel metal hydride batteries - but unlike batteries, it can be charged or discharged in just minutes or even seconds. The new device has a specific energy density of 85.6 Wh/kg at room temperature and 136 Wh/kg at 80 °C. These are the highest ever values for "electric double layer" supercapacitors based on carbon nanomaterials.
The new device was made by Bor Jang of US-based Nanotek Instruments and colleagues. It has electrodes made of graphene mixed with 5wt% Super P (an acetylene black that acts as a conductive additive) and 10wt% PTFE binder. A sheet of carbon just one atom thick, graphene is a very good electrical conductor as well as being extremely strong and flexible.The researchers coat the resulting slurry onto the surface of a current collector and assemble coin-sized capacitors in a glove box. The energy density values of the supercapacitor are comparable to that of nickel metal hydride batteries. "This new technology makes for an energy storage device that stores nearly as much energy as in a battery but which can be recharged in seconds or minutes," Jang explained. "We believe that this is truly a breakthrough in energy technology." The device might be used to recharge mobile phones, digital cameras and micro-EVs, he adds.
The team, which includes scientists from Angstron Materials in the US and Dalian University of Technology in China, are now working hard to further improve the energy density of the device. "Our goal is to make a supercapacitor that stores as much energy as the best lithium-ion batteries (for the same weight) but which can still be recharged in less than two minutes," said Jang.
His team first discovered that graphene could be used as a supercapacitor electrode material in 2006. Since then, scientists around the world have made great strides in improving the specific capacitance of these electrodes but the devices still fall short of the theoretical capacitance values of 550 F/g.
"Despite the theoretically high specific surface area of single-layer graphene (which can reach up to 2.675 m2/g), a supercapacitance of 550 F/g has not been reached in a real device because the graphene sheets tend to re-stack together," explained Jang. "We are trying to overcome this problem by developing a strategy that prevents the graphene sheets from sticking to each other face-to-face. This can be achieved if curved graphene sheets are used instead of flat ones."
Curved graphene sheets: Source Physicsworld
Graphene bandgap opened by vapor
London Calling: ST's Bozotti seeks another term
May 24, 2013
Carlo Bozotti, chief executive officer, of ST was taking questions during a financial and media analysts' day held in London ...
Miniature self-charging tracking device generates its own radio signal
Time for a new UI programming paradigm
Mouser sign global distribution agreement with Advanced Thermal Solutions
Hydrogen power enters the call center
Brussels Calling: Qualcomm wins in a wasteful industry
May 23, 2013
Is there a difference between the U.S. and Europe on green and sustainability issues? It appears there is to judge from an ...
Europe in 10 billion € bid to boost chip industry
Nujira surpasses own world record for ET PA linearity
Silica moves to fast lane in Europe's LED market
InterviewSilica moves to fast lane in Europe's LED market
In the booming market for LED lighting, electronics distributor Silica intends to lead the pack by offering technological excellence at application level. The company is currently planning to offer tailor-made ...
Filter WizardCheck out the Filter Wizard Series of articles by Filter Guru Kendall Castor-Perry which provide invaluable practical Analog Design guidelines.
Linear video channel
READER OFFERRead more
The development platform for i.MX 6Quad from element14 (built to the Freescale SABRE Lite design) is an evaluation platform featuring the powerful i.MX 6Q, a multimedia application processor with Quad ARM Cortex-A9 cores at 1.2 GHz from Freescale Semiconductor.
This month, Freescale and element14 are giving away five such platforms, worth £128.06 each, for EETimes Europe's readers to win. The platform helps evaluate the rich set of peripherals and includes a 10/100/Gb Ethernet port, SATA-II, HDMI v1.4, LVDS, parallel RGB interface, touch screen interface, analog headphone/microphone, micro TF and SD card interface, USB, serial port, JTAG, camera interface, and input keys for Android.
And the winners are...
In our previous reader offer, Pico Technology was giving away one of its recently launched PicoScope 3207B, a 2-channel USB 3.0 oscilloscope worth 1451 Euros. Lucky winner Mr L. Sanchez-Gonzalez from Spain should be receiving his PicoScope 3207B soon. Let's wish them some interesting findings with his projects.
December 15, 2011 | Texas instruments | 222901974
Unique Ser/Des technology supports encrypted video and audio content with full duplex bi-directional control channel over a single wire interface.