Today, when the dimensions of the devices are getting smaller, the need for tiny and efficient batteries is increasing Prof. Emanuel Peled and Prof. Diana Golodnicki from the School of Chemistry are developing batteries that can be installed, among other things, inside capsules for swallowing - for medical purposes, or in tiny sensors - for security uses.
Today, when the dimensions of the devices are getting smaller, the need for tiny and efficient batteries is increasing Prof. Emanuel Peled and Prof. Diana Golodnicki from the School of Chemistry are developing batteries that can be installed, among other things, inside capsules for swallowing - for medical purposes, or in tiny sensors - for security uses.
Researchers all over the world today are trying to develop a comprehensive answer to the need for tiny batteries: micro-batteries that produce a high current and also operate for a long time. "Conventional batteries are built from several layers - cathode, anode, electrolyte and current collector, which create an electrochemical reaction between them that produces electricity," explains Prof. Golodnitsky. "When you reduce the amount of material to build a tiny battery, the amount of energy also decreases, and the battery is inefficient. In addition, the electrolyte is a toxic liquid that may leak, so batteries of this type are not suitable for medical uses, inside the human body. Also, small batteries with thin layers of solid electrolyte, developed about 15 years ago, need too frequent charging. Prof. Menachem Natan from the Faculty of Engineering proposed a brilliant solution: a perforated silicon chip, containing a large number of batteries in nano dimensions. Our research group is developing tiny batteries based on Prof. Natan's idea."
The tiny batteries are built into a 1D silicon chip, which has an area of 500 cm20,000 and a thickness of 30,000 microns, and which has 50 to 30 thin holes, with a diameter of 10-10 microns, and at a distance of 40 microns from each other. With the help of smart methods of 'wet chemistry' - various coating processes in solutions - the researchers manage to place in each of the holes thin layers that make up an independent nano-battery. In total, the chip offers 10 to XNUMX times more active material for electricity generation, and XNUMX times higher power per unit area, compared to other micro-batteries.
"We are developing a variety of batteries made of different nanomaterials, to provide the right voltage for different needs and uses," says Prof. Golodnitsky. "For example, solar cells need a low voltage of 2-1.5 volts, and batteries used for medical purposes usually operate on a voltage of 3 volts or more." The potential applications of the tiny batteries are many: implants that release drugs in the body in a controlled manner; Capsules for swallowing that carry micro-cameras for internal imaging of the digestive system (endoscopy); ear implants that assist hearing; pacemakers; sensors for measuring blood pressure or insulin level in the blood; storing energy produced from the sun by small solar cells; sensors for environmental monitoring and atmospheric pressure measurement; sensors scattered in the field for security purposes; and more.
Green fuel cells
In other studies, the researchers used the methods of nanotechnology to promote applications from the energy field, especially 'green' and clean fuel cells. "A fuel cell is an electrochemical device that continuously converts chemical energy of fuel (such as hydrogen) and an oxidizing agent (such as oxygen or air) - into electrical energy," explains Prof. Peled. "The green fuel cells are environmentally friendly, because they emit only water and heat into the atmosphere, and in the last decade they have aroused great interest around the world - as a means of producing and storing energy in general and clean energy in particular. They can be used to store electricity produced from wind or solar energy, and to supply electricity to the grid or to individual homes (in combination with air conditioning), and of course also to mobile devices; However, the most promising application today is driving electric vehicles."
An important component of fuel cells are the catalysts - nanometer particles that enable the oxidation-reduction processes that occur in the fuel cell. The catalysts that exist today are usually made of platinum nanoparticles - an extremely expensive metal, the cost of which greatly limits the use of fuel cells. In fact, the price of catalysts today is about half of the price of the entire fuel cell. To optimize and cheapen the applications, Prof. Peled's team developed a new type of catalyst: a nanometer core made of another, less expensive metal, wrapped in a thin shell or subshell of platinum or a platinum alloy. These catalysts are produced by a convenient electroless deposition technique, at room temperature. They significantly reduce the cost of the fuel cell, and at the same time do not harm its performance, and sometimes even improve it.
Prof. Emanuel Peled from Tel Aviv University's School of Chemistry is a world-renowned scientist in the field of fuel cells and batteries. He was among the founders of two innovative start-up companies, Chemtronics and EnStorage, based on technologies developed in his laboratory. His group also developed unique fuel cells, which set world records in electricity output. Prof. Peled served as the head of the Wolfson Center for Applied Research in Materials and the Gordon Center for Energy Studies at Tel Aviv University and as the director of the Knowledge Center for Fuel Cells and Batteries of the Ministry of Science and Technology. He published over 150 articles, registered more than 40 patents, and won prestigious awards in Israel and around the world.
Prof. Dina Golodnitsky from Tel Aviv University's School of Chemistry specializes in the field of electrochemistry, with an emphasis on lithium batteries and energy storage by electrochemical means.
She has published more than 80 scientific articles and three chapters in scientific books, holds 12 patents and was one of the founders of the start-up company DEVIS electroscopy. Prof. Golodnitsky maintains international collaborations with leading scientists in the US and across Europe, and is a member of the scientific journal The Open Electrochemistry Journal.
