Posts Tagged ‘energy storage devices’
Tiny Battery Embedded In a Nanowire Is the Smallest Battery Yet
Now researchers at Rice University have , packing an entire lithium-ion battery into a single nanowire. The developers say it’s as small as such a device can possibly get.
Researchers led by Rice professor Pulickel Ajayan built a hybrid energy storage device, which serves as a battery and a supercapacitor. The first version sandwiched an electrolyte between a nickel/tin anode and a cathode made of a polymer called polyaniline. The cathode also served as a supercapacitor, storing lithium ions in bulk, as this explains. The prototype proved that lithium ions would move through the electrolyte and into the cathode.
Then Ajayan and colleagues incorporated this structure into a single nanowire, through a complicated process of etching and chemical washing. The goal is to make nanowires with ultra-thin separation between electrodes, so the device can remain as small as possible.
The completed wire-batteries are about 50 microns tall, which is roughly the diameter of a human hair, according to Rice.
For now, they can only charge and discharge about 20 times before they die, but researchers are trying to optimize them to last longer. The research is published in the journal ACS Nano Letters.
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Micro-Supercapacitors Could Boost Lifetime of Portable Devices
The new micro-supercapacitors have at least double the energy storage density of the best supercapacitors
Batteries can store electrical energy in chemical reactants and typically have higher energy storage densities than supercapacitors. But supercapacitors simply store energy as electrical charge and can endure a charge-discharge cycle millions of times, compared to just several thousand cycles for batteries.
"We have known for some time that supercapacitors are faster and longer-lasting alternatives to conventional batteries, so we decided to see if it would be possible to incorporate them into microelectronic devices and if there would be any advantage to doing so," said Yury Gogotsi, a materials engineer at Drexel University in Philadelphia.
Gogotsi worked with John Chmiola, a chemist at the Lawrence Berkeley National Laboratory. They etched electrodes made of monolithic carbon film into a conducting substrate of titanium carbide, and created micro-supercapacitors with an energy storage density at least twice as much as existing supercapacitors.
That suggests micro-supercapacitors can more efficiently store energy within ever-smaller physical spaces. By directly integrating the supercapacitors with the devices they power, researchers can boost the density of microelectronic devices and allow for more functionality, less complexity and enhanced redundancy.
The almost infinite cycle life of micro-supercapacitors would make them ideal for capturing and storing energy from renewable resources, and for on-chip operations to make electronic devices longer lasting, according to Chmiola.
More short-term applications would likely combine micro-supercapacitors with micro-batteries for the most possible energy storage. But the researchers eventually hope to boost super-capacitor storage to levels closer to batteries, and hold onto the supercapacitor edge regarding charge-discharge cycles. The looks bright indeed -- and we can think of a which could use more juice while doing recon.
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