Low Battery?? Yell at your Phone to Charge it....

Imagine that one day you could charge your mobile phone, just by placing them in noisy areas or by yelling at them. Then you don’t have to struggle for the dead phone battery while travelling or during an outing when you are away from power sources. It’s no more an imagination…. Scientists have come up with a postage stamp-sized microphone out of paper that could boost your phone’s battery regulating sound. 

The scientists at the Georgia Institute of Technology developed a rollable, paper-based triboelectric nanogenerator (TENG) with 125 μm thickness for harvesting sound wave energy, which is capable of delivering a maximum power density of 121 mW/m² and 968 W/m³ under a sound pressure of 117 dBSPL. The amount of power the microphone provides depends on its size, but it's around 121 milliwatts per square meter. The TENG is designed in the contact-separation mode using membranes that have rationally designed holes at one side.

How this works? The researchers used a laser to zap a grid of microscopic holes in the paper, then coated one side in copper and laid it on top of a thin sheet of Teflon, joining the two sheets at one edge. Sound waves vibrate the two sheets in different ways, causing them to come in and out of contact. This generates an electric charge, similar to the one made when your rub a balloon on your hair, which can charge a phone slowly. The vibration creates an electric charge which can be used to charge a capacitor at the rate of 0.144 V/s.

Literally it does the recycling of sound energy from the environment, where one could get free electricity from the 'waste' sounds all around us. The charge can also be converted into a range of sound frequencies, allowing the initial sounds to be amplified.

What’s a nanogenerator? A nanogenerator is a device that utilizes piezoelectrics, triboelectrics, or paraelectrics, or all three of them, to convert mechanical action, thermal action, or other action into electricity for powering small electronic devices, mostly by converting mechanical energy. Triboelectric nanogenerator (TENG) uses the electrostatic charge created due to the triboelectrification process as a driving force for electron flow to an external load. Using this process today, we can achieve 55 percent energy conversion efficiency, the best so far. To know more about nanogenerators please follow the link to Wiki 

The scientists said the concept and design could be applied to a variety of circumstances for energy harvesting or sensing purposes.  The advantages of a broad working bandwidth, thin structure, and flexibility, a self-powered microphone for sound recording with rolled structure is demonstrated for all-sound recording without an angular dependence. The concept can be extensively applied to a variety of circumstances for either energy-harvesting or sensing purposes, would be toward wearable and flexible electronics, military surveillance, jet engine noise reduction, a low-cost implantable human ear and wireless technology.

The main benefit of such a microphone is that it could harvest acoustic energy to top up a phone charge on the go. The TENG can be implemented onto a commercial cell phone for acoustic energy harvesting from human talking. While the hope is that sound-powered devices could replace conventional chargers soon. It may not produce quite enough energy to do away with current charging methods entirely as it would only provide a small amount of power rather than fully charging the phone.

Transforming sound into battery power is not a novel idea. We first heard of a sound-charging phone that would power itself with the user's voice when a team of Korean researchers revealed their prototype in 2011.  However, it seems much more likely that a sound-powered charging may soon be a reality.

Now Battery can be charged in 1 Minute.

Our smartphones have become more advanced and power-hungry over the last few years, scientists have been looking at ways to improve battery life for some time. Finally they have come with cheap, long lasting and quick to recharge batteries. This is the battery for your phone you have been waiting for. New battery technology uses aluminium and graphite, and promises to make charging much quicker, less often and far safer. Stanford University researchers have developed an ultra-fast charging aluminium battery.

Conventional alkaline batteries are bad for the environment while lithium-ion batteries used in millions of laptops and smartphones can unexpectedly burst into flames and take a long time to charge. However the new battery is fast-charging, long-lasting and inexpensive. It is also flexible too and can be used in new folding devices in development.

The prototype consists of a soft pouch, containing aluminium for one electrode and a graphite foam, a sponge-like pattern of tiny whiskers of the stuff, surrounding many empty pockets, which allows ions in the electrolyte solution very easy access to the graphite, helping the battery to work faster.

When the battery discharges, aluminium dissolves at the anode, while aluminium-containing ions slide into the spaces between atomic graphite layers at the cathode. When it charges again, the reverse occurs, depositing metallic aluminium metal back on the anode.

Because it is lightweight and inexpensive, aluminium has attracted interest from battery engineers for many years, but it has never yielded a viable product. The trouble for engineers has been finding the right material to pair with aluminium, a material capable of producing high voltage especially after multiple cycles of rapid charging and discharging. Graphite, a form of carbon in which the atoms form thin, flat sheets, turned out to deliver very good performance, while also being similarly lightweight, cheap and widely available.

It offers safety advantages over lithium batteries that power most mobile devices, the materials used are less volatile and do not catch fire if perforated. Lithium-ion batteries can be a fire hazard. While lithium-ion battery can take hours to charge, the new battery recharges in one minute. Also the electrolyte is basically a salt that's liquid at room temperature, held inside a flexible polymer-coated pouch, so it's very safe. This is in contrast with the flammable electrolytes used in lithium-ion batteries.

The new battery can be recharged around 7,500 times. Typical lithium-ion batteries used in everything from smartphones and laptops to electric cars last around 1,000 recharge cycles. Another feature of the aluminium battery is flexibility. You can bend it and fold it, so it has the potential for use in flexible electronic devices.

The battery can generate around 2 volts of electricity, which is less than the 3.6 volts from a conventional lithium-ion battery, but the highest achieved with aluminium. Its energy density, the amount of electrical energy stored in a given unit of mass, is also lower. The aluminium-ion battery developed has an energy density of 40 watts per kilogram compared to between 100 and 260 watts per kilogram for lithium ion. However, improvements in the cathode material could eventually lead to a higher voltage and energy density, the researchers believe. But the team already managed to charge a smartphone in a minute by strapping two aluminium batteries together and put them into an adapter.

According to Clare Grey from the University of Cambridge, turning the prototype into a larger commercial product is challenging. One problem is that the process of squeezing ions in between the graphite sheets can cause the material to expand and contract, which is "bad news for the battery”. Also, the bigger the graphite sheets are, the further the ions have got to diffuse in, so the slower it gets. So part of reason it's got this high rate is that it's got very small platelets of graphite.

Beyond small electronics devices, it can be used for storing renewable energy on the electrical grid, which could solve some of the current problems presented by inconsistent renewable sources like wind and solar. Lithium cells’ durability means they aren't ideally suited for this application. But aluminium cell’s ability to last for tens of thousands of charges, and their rapid charge and discharge, offers a possible future alternative.

In the video Stanford graduate student Ming Gong and postdoctoral scholar Yingpeng Wu demonstrate how the new technology could offer a safe alternative to lithium-ion and other batteries.

Its unprecedented speed in charging makes it attractive and impressive. It has all features a dream battery would have: inexpensive electrodes, good safety, high-speed charging, flexibility and long cycle life. This technology shows a promise which is unlikely to be featuring in our smartphones any time soon. It’s sure that these environment friendly aluminium-ion batteries could result in safer consumer electronics in future.

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Visible Solar Windows….!!!!

Researchers are back with another incredible technology, a fully transparent solar concentrator which has the capability of turning any window or sheet of glass into a photovoltaic solar cell. This new transparent solar cell could be used as a window, which was once thought to be impossible, because traditional solar panels absorb light and turn it into energy, but a transparent surface is not typically able to absorb light. Also vision is not compromised.

Just think, you could keep your phone charged whenever you are outdoors or in the sun. The incoming solar energy of tall buildings can also be harvested using this. Researchers at Michigan State University have developed a new type of solar concentrator which uses transparent, uncoloured plastic that when placed over a window creates solar energy while allowing people to actually see through the window. According to lead researcher Richard Lunt, the team is confident that these transparent solar connectors can be efficiently used in numerous settings from “tall buildings with lots of windows or any kind of mobile device that demands high aesthetic quality like a phone or e-reader.”

Researchers opted for a different system called a transparent luminescent solar concentrator (TLSC), which contains organic salts that absorb specific non-visible wavelengths of sunlight, ultraviolet and infrared light, which they then glow as another wavelength of infrared light (also non-visible). This emitted light is then guided towards traditional photovoltaic solar cells which are able to trap the energy and convert it into electricity. Since the absorbed wavelengths are not visible for us, the material looks transparent.

The most important feature is that harvesting the light for power can be layered on top of a clear piece of glass without completely weakening the sunlight’s ability to pass through it. The perimeter of the cell contains small photovoltaic strips, which means it is basically a miniaturized version of a solar panel. These react with infrared light, which is invisible to the naked eye and produces solar electricity.

Solar concentrators are different from solar panels because they trap light and then direct it outward to the edge of the conductor where the solar cells, which generate energy, are located. They are more efficient and cost-effective than solar panels, which lose a lot of energy to heat and require expensive devices to direct as much sunlight as possible toward them.

The efficiency is currently low 1%, but researchers are confident that they can reach at least 5% in the near future. You may be thinking these figures are so small, but multiply that by every window in a house, or car and you can begin to see that this could be very beneficial, particularly for skyscrapers and office buildings where virtually every wall is just windows.

The new technology would lead to energy efficient systems as the newly developed transparent luminescent solar concentrator can be used on buildings, cell phones and any other device that has a clear surface. Their technology is an invisible film that can go on any surface and generate power, which could lead to cell phones, and tablets that never run out of batteries or skyscrapers that can use their massive banks of windows as solar panels. 

Research in the production of energy from solar cells placed around luminescent plastic-like materials is not new. These past efforts, however, have yielded poor results. The energy production was inefficient and the materials were highly coloured.

One of the benefits of this new development is its flexibility. It is a transparent luminescent solar concentrator and can be used on buildings, cell phones and any other device that has a clear surface. While the technology is at an early stage, it has the potential to be scaled to commercial or industrial applications with an affordable cost.

A transparent solar panel is something like an oxymoron. I.e. Solar cells, mainly the photovoltaic kind, make energy by absorbing photons (sunlight) and converting them into electrons (electricity). Then if a material is transparent by definition it means that all of the light passes through the medium to strike the back of your eye. This is why previous transparent solar cells have actually only been partially transparent obscuring the view.

The researchers are confident that the technology can be used all the way from large industrial and commercial applications being affordable. So far, one of the larger barriers to large-scale adoption of solar power is the intrusive nature of solar panels. If we can produce large amounts of solar power from sheets of glass and plastic that look like normal sheets of glass and plastic, then that would be big.

This inspiring innovation could greatly expand the reach of solar power. In fact energy from the sun itself is virtually free! All you need is the solar connector and you are good to go. This also means that buildings of the future are covered in the energy-producing panels. Anyways renewable energy is our future and its scope is very exciting…..


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