New nanotechnology batteries

In order to save money and energy, many people today purchase hybrid electric vehicles or install solar panels on the roofs of their houses. However, there is a flaw in both of these systems - the technology used to store the energy and the electric power are not efficient enough. Researchers from the University of Maryland seek to solve the problem using nanotechnology

Researchers from the Maryland Center for Nanotechnology at the University of Maryland have developed a new electrical energy storage system based on alternative energy sources that are, in some cases, ten times more efficient than those currently on the market.

In order to save money and energy, many people today purchase hybrid electric vehicles or install solar panels on the roofs of their houses. However, there is a flaw in both of these systems - the technology used to store the energy and the electric power are not efficient enough.

Batteries suitable for vehicles do not store enough energy in their content to travel long distances, and in addition - it takes hours to charge them and they do not provide enough power for acceleration. Renewable sources such as solar and wind energy provide energy only part of the time, and the devices to store the energy resulting from them are expensive and inefficient enough.

Researchers from the University of Maryland have developed new systems for storing electrical energy that comes from alternative energy sources, which are, in some cases, ten times more efficient than those available on the market. Their research findings recently appeared in the journal Nature Nanotechnology.

"Renewable energy sources such as solar and wind energy constitute an unpredictable energy reserve that is sensitive to the time of day and the seasons of the year, while the energy resulting from them must be converted and stored as electrical energy until the time of demand," said Gary Rubloff, director of the Center for Nanotechnology at the University of Maryland.

"Common devices for storing and transferring electrical energy - batteries and capacitors - are unable to provide the necessary combination of high energy density, high power and fast charging that are all essential to our future energy demands."

The research team developed a method to significantly increase the performance of electrical energy storage devices. Using a new process important to nanotechnology, they made millions of identical nanostructures with shapes suitable for the rapid transfer of electron energy to and from very wide surfaces where they are deposited. Different substances, of course, behave according to physical laws of nature. The researchers took advantage of a rare combination of these behaviors, known as self-assembly, self-limiting reaction, and self-alignment, to build millions, and in fact an infinite number of tiny, virtually identical nanostructures capable of absorbing , to store and transfer electrical energy.

"These devices utilize unique combinations of materials, processes and building structures to optimize both energy and power density - combinations which, taken together, hold real promise for the creation of the next generation applied technology, and around it, it is hoped, a new area of ​​technological economy, ” adds the lead researcher.

The main purpose of an electric energy storage system is to achieve, simultaneously, both high power and high energy density to allow devices to store large amounts of energy, transfer it with great power and charge quickly," he points out.

Electrical energy storage devices fall into three different categories. Batteries, especially lithium-ion, store large amounts of energy but are unable to provide high power or fast charging. Electrochemical capacitors, based on electrochemical phenomena, also provide high power at the expense of low energy density. Contrary to this, electrostatic capacitors are based on physical means only, storing an electric charge according to the area of ​​two conductors. This allows them to provide high power and fast charging but at the cost of low energy density.

The research team's new devices are electrostatic nanoparticles that dramatically increase the energy storage density of such devices - by a factor of ten relative to existing commercial devices - without sacrificing the high power they commonly provide. This advance brings electrostatic devices to a performance level competitive with electrochemical capacitors and introduces a new candidate in the field of next-generation electrical energy storage.

Where will these nanodevices appear? The researchers emphasize that they are developing the technology for mass production as layers of devices that look like thin panels, similar to solar panels or thin displays in computers and televisions, all of which are sold at low prices. Several such energy storage panels will be connected together into a car battery or solar panel. In the future, they anticipate that the same nanotechnology could provide new methods of energy capture that could be included in commercial storage devices.

This progress came shortly after another achievement - a significant improvement in the performance of electrochemical capacitors called "supercapacitors" made by the same group and recently published in the Journal of the American Chemical Society. Efforts are being made to achieve similar progress in the energy density of lithium ion batteries, but with higher power density.

"The successes of the University of Maryland are based on the collaboration of experts coming from a wide variety of nanoscience and nanotechnology fields with scientists who are already at the center of energy research," says the lead researcher.

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