This possibility is one of the reasons for the current interest in building the capacity to store electrical energy directly into a wide range of products such as a laptop
whose casing serves as its battery or an electric car powered by energy stored in its chassis
or a home where the dry wall and siding store the electricity that runs the lights
and appliances. hese devices demonstrateâ##for the first time as far as we can tellâ##that it is possible to create materials that can store
and discharge significant amounts of electricity while they are subject to realistic static loads and dynamic forces such as vibrations or impactssays Cary Pint assistant professor of mechanical engineering at Vanderbilt University.
and Energy Devices Laboratory there. ndrew has managed to make our dream of structural energy storage materials into a realitysays Pint.
which a wide variety of technologies are developed in the future. hen you can integrate energy into the components used to build systems it opens the door to a whole new world of technological possibilities.
The new device that Pint and Westover have developed is a supercapacitor that stores electricity by assembling electrically charged ions on the surface of a porous material instead of storing it in chemical reactions the way batteries do.
and operate for millions of cycles instead of thousands of cycles like batteries. In a paper appearing online in the journal Nano Letters Pint
Furthermore the mechanical robustness of the device doesn t compromise its energy storage capability. n an unpackaged structurally integrated state our supercapacitor can store more energy
One area where supercapacitors lag behind batteries is in electrical energy storage capability: Supercaps must be larger and heavier to store the same amount of energy as lithium-ion batteries.
However the difference is not as important when considering multifunctional energy storage systems. attery performance metrics change when you re putting energy storage into heavy materials that are needed already for structural integritysays Pint. upercapacitors store ten times less energy than current lithium-ion batteries
but they can last a thousand times longer. That means they are suited better for structural applications.
Sandwiched between the two electrodes is a polymer film that acts as a reservoir of charged ions similar to the role of the electrolyte paste in a battery.
and solidifies it forms an extremely strong mechanical bond. he biggest problem with designing load-bearing supercaps is preventing them from delaminatingsays Westover. ombining nanoporous material with the polymer electrolyte bonds the layers together tighter than superglue. he use
and solar cells but Pint and Westover are confident that the rules that govern the load-bearing character of their design will carry over to other materials such as carbon nanotubes and lightweight porous metals like aluminum.
The US Department of energy s Advanced Research Project Agency for Energy is investing $8. 7 million in research projects that focus specifically on incorporating energy storage into structural materials.
There have also been recent press reports of several major efforts to develop multifunctional materials or structural batteries for use in electric vehicles and for military applications.
which is supported by the Office of Basic energy Sciences of the US Department of energy. Source: Vanderbilt Universityyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license m
#eurogrid chips mimic the brain to use less energy Compared to the human brain, today computers are ridiculously slow
and take about 40,000 times more power to run. rom a pure energy perspective, the brain is hard to match,
explains Boahen. chieving this level of energy efficiency while offering greater configurability and scale is the ultimate challenge neuromorphic engineers face.
#To save energy, computers go for good enough Purdue University rightoriginal Studyposted by Emil Venere-Purdue on December 23 2013computers capable of pproximate computingcould potentially double efficiency
and reduce energy use. Researchers are developing computers that could perform calculations good enough for certain tasks that don t require perfect accuracy. he need for approximate computing is driven by two factors:
and saps energy. f I asked you to divide 500 by 21 and I asked you
They often compute to the same level of accuracy all the time. urdue researchers have developed a range of hardware techniques to demonstrate approximate computing showing a potential for improvements in energy efficiency.
what we have seen is that we can easily double energy efficiency. n other recent work led by former doctoral student Vinay K. Chippa the Purdue team fabricated an approximate cceleratorfor recognition
As it moves along a carbon-nanotube track it continuously harvests energy from strands of RNA molecules vital to a variety of roles in living cells
and viruses. ur motors extract chemical energy from RNA molecules decorated on the nanotubes and use that energy to fuel autonomous walking along the carbon nanotube trackchoi says.
The core is made of an enzyme that cleaves off part of a strand of RNA. After cleavage the upper DNA arm moves forward binding with the next strand of RNA
flexible batteries made from electrically conductive paper; new drug-delivery technologies; transparent flexible displays for electronic devices; special filters for water purification;
000 LED bulbs by stomping one foot One day it may be possible to harvest the otherwise wasted energy of your footsteps
what s technically known as the triboelectric effect to create surprising amounts of electric power by rubbing or touching two different materials together.
and sensor applicationssays Zhong Lin Wang a professor in the School of Materials science and engineering. his opens up a source of energy by harvesting power from activities of all kinds. n its simplest form the triboelectric generator
Generators producing DC current have also been built. he fact that an electric charge can be produced through triboelectrification is well knownwang explains. hat we have introduced is a gap separation technique that produces a voltage drop
which leads to a current flow in the external load allowing the charge to be used. his generator can convert random mechanical energy from our environment into electric energy. ince their first publication on the research Wang
and his research team have increased the power output density of their triboelectric generator by a factor of 100000â##reporting that a square meter of single-layer material can now produce as much as 300 watts.
The researchers have expanded the range of energy-gathering techniques from ower shirtscontaining pockets of the generating material to shoe inserts whistles foot pedals floor mats backpacks
Their latest paper published in the journal ACS Nano described harvesting energy from the touch pad of a laptop computer.
Beyond its use as a power source Wang is also using the triboelectric effect for sensing without an external power source.
because they re very poor conductors. nter graphene the single-atom-thick sheet of carbon that both conducts electricity and because it s so thin allows radio frequencies to pass unhindered.
and Volman recognized the potential. ristine graphene transmits electricity ballistically and would not produce enough heat to melt ice
Called a near broken-gap tunnel field effect transistor (TFET) the new device uses the quantum mechanical tunneling of electrons through an ultrathin energy barrier to provide high current at low voltage.
The results can be seen in batteries that drain faster and increasing heat dissipation that can damage delicate electronic circuits.
Various new types of transistor architecture using materials other than the standard silicon are being studied to overcome the power consumption challenge. his transistor has previously been developed in our lab to replace MOSFET transistors for logic applications
while draining the battery requires frequent replacement surgery. The researchers led by Suman Datta professor of electrical engineering tuned the material composition of the indium gallium arsenide/gallium arsenide antimony
so that the energy barrier was close to zeroâ##or near broken gap which allowed electrons to tunnel through the barrier when desired.
are combined with the reactive substance a battery-powered handheld reader is used then to detect any fluorescence
We are learning so many rules for calculating things that other people cannot compute in atoms in atomic crystals. he ratio affects the energy of the faces of the crystals
Ratios that don t follow the recipe lead to large fluctuations in energy and result in a sphere not a faceted crystal she explained.
With the correct ratio the energies fluctuate less and result in a crystal every time. magine having a million balls of two colors some red some blue in a container
and energy for all the particles to arrange themselves and find the spots they should be inmirkin says.
when triggered by an external source of energy. However electrons and holes in semiconductors are charged particles
when the so-called Fermi energy is much larger than the thermal energy. When pumped by a strong laser these quantum degenerate particles gathered energy
and released it as light at the Fermi edge: the energy level of the most energetic particles in the system.
As the electrons and holes combined to release photons the edge shifted to lower energy particles
and tested a new approach to cloakingâ##by surrounding an object with small antennas that collectively radiate an electromagnetic field.
and processing radio-frequency signals are much harder to miniaturizesays project co-leader Kenneth Shepard an electrical engineering professor. hese off-chip components take up a lot of space and electrical power.
#This is the first battery electrode that heals itself Stanford university rightoriginal Studyposted by Glennda Chui-Stanford on November 19 2013scientists have created the world s first self-healing battery electrode
and say it could open the door to better batteries for phones cars and other gadgets.
and spontaneously heals tiny cracks that develop during battery operation. elf-healing is very important for the survival and long lifetimes of animals
and plantssays Chao Wang a postdoctoral researcher at Stanford university and one of two principal authors of the paper. e want to incorporate this feature into lithium ion batteries
For the battery project Chao added tiny nanoparticles of carbon to the polymer so it would conduct electricity. e found that silicon electrodes lasted 10 times longer
which repaired any cracks within just a few hoursbao says. heir capacity for storing energy is in the practical range now
and from all our data it looks like it s working. esearchers worldwide are racing to find ways to store more energy in the negative electrodes of lithium ion batteries to achieve higher performance while reducing weight.
it has a high capacity for soaking up lithium ions from the battery fluid during charging and then releasing them
when the battery is put to work. But this high capacity comes at a price: silicon electrodes swell to three times their normal size
and shrink back down again each time the battery charges and discharges. The brittle material soon cracks and falls apart degrading battery performance.
This is a problem for all electrodes in high-capacity batteries says Hui Wu a former Stanford postdoc who is now a faculty member at Tsinghua University in Beijing
and the other principal author of the paper. To make the self-healing coating scientists deliberately weakened some of the chemical bonds within polymersâ â##long chainlike molecules with many identical units.
The resulting material breaks easily but the broken ends are drawn chemically to each other and quickly link up again mimicking the process that allows biological molecules such as DNA to assemble rearrange and break down.
Researchers in Cui s lab and elsewhere have tested a number of ways to keep silicon electrodes intact
and solar cell industry is the first solution that seems to offer a practical road forward Cui says.
and the Precourt Institute for Energy at Stanford funded the work. Source: Stanford Universityyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license
The shape of the damaged area can be explained by the fact that the energy was deposited over a range of altitudes.
#Crystal structure could push the limits of solar cells University of Pennsylvania right Original Studyposted by Evan Lerner-Pennsylvania on November 13 2013 A new model for solar cell construction may ultimately make them less expensive easier to manufacture
and more efficient at harvesting energy from the sun. For solar panels wringing every drop of energy from as many photons as possible is imperative.
 This goal has sent researchers on a quest to boost the energy-absorption efficiency of photovoltaic devices
As reported in the journal Nature existing solar cells all work in the same fundamental way:
or polarity solar cells need to be made of two materials. Once an excited electron crosses over the interface from the material that absorbs the light to the material that will conduct the current it can't cross back giving it a direction. here's a small category of materials
and of materials science and engineering at the University of Pennsylvania. e call this the bulk photovoltaic effect rather than the interface effect that happens in existing solar cells.
since the 1970s but we don't make solar cells this way because they have only been demonstrated with ultraviolet light
and most of the energy from the sun is in the visible and infrared spectrum. â#Finding a material that exhibits the bulk photovoltaic effect for visible light would greatly simplify solar cell construction.
Moreover it would be a way around an inefficiency intrinsic to interfacial solar cells known as the Shockley-Queisser limit where some of the energy from photons is lost as electrons wait to make the jump from one material to the other. hink of photons coming from the sun
as coins raining down on you with the different frequencies of light being like pennies nickels dimes and so on.
and silver dollars but they'll all only be worth the energy equivalent of 10 cents
even though you're losing most of the energy from the UV you do get. s no known materials exhibited the bulk photovoltaic effect for visible light the research team worked to devise how a new one might be fashioned and its properties measured.
Moreover the ability to tune the final product's bandgap via the percentage of barium nickel niobate adds another potential advantage over interfacial solar cells. he parent's bandgap is in the UV rangesays Jonathan E. Spanier
which is another very useful trait. nother way to get around the inefficiency imposed by the Shockley-Queisser limit in interfacial solar cells is to effectively stack several solar cells with different bandgaps on top of
These multi-junction solar cells have a top layer with a high bandgap which catches the most valuable photons
Successive layers have lower and lower bandgaps getting the most energy out of each photon
and cost of the solar cell. he family of materials we've made with the bulk photovoltaic effect goes through the entire solar spectrumrappe says. o we could grow one material
but gently change the composition as we're growing resulting in a single material that performs like a multi-junction solar cell.?
and earth-abundant elements unlike compound semiconductor materials currently used in efficient thin-film solar cell technology. he research was supported by the Energy Commercialization Institute of Ben Franklin Technology Partners the Department of energy's Office of Basic Sciences
LEDS use less energy emit less heat last longer and are less hazardous to the environment than traditional lighting.
Lower-efficiency incandescent and fluorescent bulbsâ##which use relatively more energy to produce lightâ##could become antiquated fixtures of the past. ur target is to get to 90 percent efficiency
or 300 lumens per wattsays Denbaars who also is a professor of electrical and computer engineering and co-director of the Solid State Lighting & Energy Center.
#Photon detector is quantum leap from semiconductors A new superconducting detector array can measure the energy of individual photons.
MKIDS which operate at cryogenic temperatures (typically 0. 1 Kelvin) allow astronomers to determine the energy
#Wireless device grabs lost energy from Wi-fi Using inexpensive materials configured and tuned to capture microwave signals researchers have designed a power harvesting device with efficiency similar to that of modern solar panels.
The device wirelessly converts the microwave signal to direct current voltage capable of recharging a cell phone battery or other small electronic device according to a report appearing in Applied Physics Letters.
It operates on a similar principle to solar panels which convert light energy into electrical current. But this versatile energy harvester could be tuned to harvest the signal from other energy sources including satellite signals sound signals
or Wi-fi signals the researchers say. The key to the power harvester lies in its application of metamaterials engineered structures that can capture various forms of wave energy and tune them for useful applications.
Undergraduate engineering student Allen Hawkes working with graduate student Alexander Katko and lead investigator Steven Cummer professor of electrical and computer engineering designed an electrical circuit capable of harvesting microwaves.
They used a series of five fiberglass and copper energy conductors wired together on a circuit board to convert microwaves into 7. 3v of electrical energy.
By comparison Universal serial bus (USB) chargers for small electronic devices provide about 5v of power. e were aiming for the highest energy efficiency we could achievesays Hawkes. e had been getting energy efficiency around 6 to 10 percent
but with this design we were able to dramatically improve energy conversion to 37 percent which is comparable to
what is achieved in solar cells.?It s possible to use this design for a lot of different frequencies
and types of energy including vibration and sound energy harvestingkatko says. ntil now a lot of work with metamaterials has been theoretical.
We are showing that with a little work these materials can be useful for consumer applications
. or instance a metamaterial coating could be applied to the ceiling of a room to redirect and recover a Wi-fi signal that would
Another application could be to improve the energy efficiency of appliances by wirelessly recovering power that is now lost during use. he properties of metamaterials allow for design flexibility not possible with ordinary devices like antennassays Katko. hen traditional antennas are close to each other in space they talk to each other
This feature could in principle allow people living in locations without ready access to a conventional power outlet to harvest energy from a nearby cell phone tower
The small amount of energy generated from these signals might power a sensor network in a remote location such as a mountaintop
Not so. nimals are a lot more clever with their mechanics than we often realizecowan says. y using just a little extra energy to control the opposing forces they create during those small shifts in direction animals seem to increase both stability
#How food can build better lithium batteries Cornell University rightoriginal Studyposted by Anne Ju-Cornell on October 29 2013a component of corn starch
and the yolk-shell structure of eggs can improve the durability and performance of lithium-sulfur battery cathodes report researchers.
Lithium-sulfur batteries are a promising alternative to today s lithium-ion batteries. here is currently a great need for high-energy long-life
and low-cost energy storage materials and lithium sulfur batteries are one of the most promising candidatessays Weidong Zhou a former postdoctoral researcher in Professor Hector Abruã a s lab at Cornell
and the Journal of the American Chemical Society. rom electric vehicles to solar and wind power applications for better lithium-based battery technologies are countless.?
Lithium-sulfur batteries could potentially offer about five times the energy density of today s typically used lithium-ion batteriessays Yingchao Yu a Phd student with Abruã a
and co-first author on the JACS publication. ut a lithium-sulfur battery is not a stable system as its capacity tends to fade over a short period of time. fter about 50 charge cycles the energy density of a lithium-sulfur
battery decreases rapidly due to a phenomenon called the polysulfide shuttling effect which is when the polysulfide chains in the battery s cathode (positive end) dissolve in the electrolyte the ionizing liquid that allows electrons to flow.
To combat this problem and stabilize the sulfur the researchers used amylopectin a polysaccharide that s a main component of corn starch. he corn starch can effectively wrap the graphene oxide-sulfide composite through the hydrogen bonding to confine the polysulfide among the carbon layerssays Hao Chen
and professor of chemistry and chemical biology. s an additive it greatly improves the cycling stability of the battery. n another approach to improving lithium-sulfur battery durability the researchers also report a new way
but the new method provides an internal void within the polymer shell called a olk-shellstructure. hen the lithium-sulfur battery was discharged fully the volume of the sulfur expanded dramatically to 200 percent.
The Department of energy and the Energy Materials Center at Cornell an Energy Frontier Research center funded by the US DOE funded the papers.
and requires no batteries it could allow the manufacture of small lightweight and inexpensive location and identification tags for animals infrastructure (pipelines conduits for example)
or the batteries have no charge remaining. n addition to the applications discussed above such technology could be extended to other radiations such as magnetic resonance imaging (MRI) and light detection and ranging (LIDAR)
In fact it should be possible to construct these power cells out of the excess silicon that exists in the current generation of solar cells sensors mobile phones
. ut we ve found an easy way to do it. nstead of storing energy in chemical reactions the way batteries do upercapsstore electricity by assembling ions on the surface of a porous material.
and operate for a few million cycles instead of a few thousand cycles like batteries. These properties have allowed commercial supercapacitors
which are made out of activated carbon to capture a few niche markets such as storing energy captured by regenerative braking systems on buses
Supercapacitors still lag behind the electrical energy storage capability of lithium-ion batteries so they are too bulky to power most consumer devices.
because it reacts readily with some of chemicals in the electrolytes that provide the ions that store the electrical charge.
And 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.
Pint and his group argue that this approach isn t limited to graphene. he 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 storagehe
since it is very expensive and wasteful to produce thin silicon wafers. int s group is currently using this approach to develop energy storage that can be formed in the excess materials or on the unused backsides of solar cells and sensors.
The supercapacitors would store excess electricity that the cells generate at midday and release it when the demand peaks in the afternoon. ll the things that define us in a modern environment require electricitysays Pint. he more that we can integrate power storage into existing materials
A new iller materialcan help put an end to dropped calls by making cell phones that tune to different frequencies without wasting battery power.
what people have been using for decadessays Darrell Schlom professor of industrial chemistry at Cornell University who led the international research team. hat we have discovered is the world's lowest-loss tunable dielectric. ossrefers to wasted energy
which drains cell phone batteries. The new type of tunable dielectric could greatly improve the performance of microwave circuit capacitors found in every cell phone
#Ceramic converter tackles solar cell problem Stanford university rightoriginal Studyposted by Mark Shwartz-Stanford on October 21 2013coating a solar cell component in ceramics makes it more heat resistant
which can be absorbed by solar cells to make electricity a technology known as thermophotovoltaics. Unlike earlier prototypes that fell apart before temperatures reached 2200 degrees Fahrenheit (1200 degrees Celsius) the new thermal emitter remains stable at temperatures as high as 2500 F
A typical solar cell has a silicon semiconductor that absorbs sunlight directly and converts it into electrical energy.
But silicon semiconductors only respond to infrared light. Higher energy light waves including most of the visible light spectrum are wasted as heat
while lower energy waves simply pass through the solar panel. n theory conventional single-junction solar cells can only achieve an efficiency level of about 34 percent
Instead of sending sunlight directly to the solar cell thermophotovoltaic systems have an intermediate component that consists of two parts:
which is beamed then to the solar cell. ssentially we tailor the light to shorter wavelengths that are ideal for driving a solar cellfan explains. hat raises the theoretical efficiency of the cell to 80 percent
which is quite remarkable. o far thermophotovoltaic systems have achieved only an efficiency level of about 8 percent Braun notes.
which is made typically of tungsten##an abundant material also used in conventional light bulbs. ur thermal emitters have a complex three-dimensional nanostructure that has to withstand temperatures above 1800 F 1000 C to be practicalbraun says n fact the hotter
and his colleagues at Stanford who confirmed that devices were still capable of producing infrared light waves that are ideal for running solar cells. hese results are unprecedentedsays former Illinois graduate student Kevin Arpin the lead author of the study. e demonstrated for the first time that ceramics
could help advance thermophotovoltaics as well other areas of research including energy harvesting from waste heat high-temperature catalysis
and determine if the experimental thermal emitters can deliver infrared light to a working solar cell. e ve demonstrated that the tailoring of optical properties at high temperatures is possiblebraun says. afnium
is established well. opefully these results will motivate the thermophotovoltaics community to take another look at ceramics
and Energy project and the Department of energy s Light-Material Interactions in Energy conversion Center supported the work along with the National Science Foundation and the Research Triangle Solar fuels Institute.
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