PORTLAND, Ore. — Say goodbye to your phone battery and charger. A new structural material could transform a mobile device's entire case into a hybrid super-capacitor/battery, making traditional batteries obsolete.
Researchers from Vanderbilt University's Nanomaterials and Energy Devices Laboratory are now designing materials that combine the best aspects of super-capacitors and batteries into a single hybrid material suitable for making such device cases. While the material's energy density is currently less than that of a lithium-ion battery, it makes up for density by the much bigger volume of a case -- plus it eliminates the space needed for a battery.
"My group is now looking at developing hybrid capacitors -- batteries that behave like capacitors -- that can maintain ultra-long cycling lifetimes like supercaps but store and deliver almost as much energy as current lithium-ion batteries," professor Cary Pint told EE Times about his work with doctoral candidate Andrew Westover at Vanderbilt.
Pint has hopes that his hybrid super-capacitor material can be built into the structure of all types of construction projects -- from the siding and drywall of homes to the chassis of airplanes.
"One of the key motivating factors in pursuing this technology was to develop energy storage materials that could be integrated into homes, which would increase the economic value of solar cells that are placed on the roof and enable a distributed energy electric grid system," Pint told us.
Announced separately from the Vanderbilt super-capacitor, Apple's patent US008730179B2 features a photovoltaic touchscreen that could conceivably harvest enough ambient light to keep a mobile device with a super-capacitor case recharged with no power cord.
On a smaller scale, last week, Apple patented a method of embedding a solar panel into a touch screen. Although announced separately from the Vanderbilt super-capacitor, a mobile device with a photovoltaic touchscreen combined with a super-capacitor case could conceivably harvest enough ambient light to keep it recharged with no power cord.
"In this sort of device," Pint says. "It is the same story, but at a much smaller scale of a portable device.
No matter the application, however, the purpose is always the same -- that is, to transform structural materials into energy storage devices that still have the same load-bearing durability of traditional structural materials, but harbor inside them energy storage systems whose lifetime exceeds the lifetime of the object for which they are the building materials.
"I suppose the key takeaway from our work is that load-bearing energy storage that doesn't compromise the charge storage capability of the materials used in the system is a reality now, and there are a lot of directions this area can go from here."
This structural material is actually a super-capacitor that could store energy in a devices case rather than require an extra battery component.
(Source: Vanderbilt University)
Pint's super-capacitors currently store 10x less energy than a lithium-ion battery, but make up for that in the volume of the structure they are a part of, plus they last 1,000x longer than a battery, making them suitable for mobile devices, automobiles, aircraft, homes, and more.
"I would also argue that in some cases, 'total energy' should be a metric that matters to us. 10x less energy stored over 1,000x as many discharge cycles, this means that 100x more energy is stored over the lifetime of the system. That means they are better suited for structural applications. It doesn't make sense to develop materials to build a home, car chassis, or aerospace vehicle if you have to replace them every few years because they go dead."
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