Smartphones, tablets and other electronic devices run on rechargeable batteries, but after thousands of cycles of use, the batteries begin to lose their ability to hold a charge. Most modern batteries are lithium, but over time the lithium inside the battery will corrode.
Instead of lithium, researchers at the University of California, Irvine used gold nanowires to store electrical charge, and the system they developed was found to be superior to traditional lithium batteries. It withstood 200,000 recharge cycles without significant deterioration in properties and signs of corrosion.
However, they still do not fully understand why this is happening. The original idea of the experiment was to make a solid electrolyte battery, in which an electrolyte paste is used instead of a liquid electrolyte. Liquid batteries, such as lithium, are highly flammable and temperature sensitive. The researchers experimented with the use of thick, conductive pastes.
“We started a cycle of recharging the device, and then realized that it was not going to 'die',” said study leader Reginald Penner. "But so far we do not understand the mechanism of this."
According to the new technology, a gold nanowire is used to create batteries, the size is not thicker than a bacterium, covered with manganese oxide and protected by a layer of electrolyte paste. The paste interacts with the oxide coating to prevent corrosion. The longer the nanowire, the larger the surface area, and the more charge it can hold. Other researchers have experimented with nanowires for a long time, but unlike them, scientists at the University of Irvine first proposed using a protective paste.
“The paste does a lot more than just hold the wires together. It appears to make the metal oxide softer and more resistant to cracking,”Penner said.
This technology promises to increase battery life in consumer electronics by 400 times, but so far the test platform is not a real battery. Batteries have an anode through which electric current enters the system and a cathode through which it exits. Instead, the scientists tied two cathodes together, which replace each other when charging. The continuous cycle of changing cathodes makes it an ideal system for testing multiple recharges.
Penner says it's like a continuous process of pouring water from one cup to another and back again. After several hundred pouring cycles, some of the water is usually poured out, reducing the “charge”. But Penner's system, when pouring water between "cups" 200 thousand times, loses only about 5 percent.
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Despite the use of negligible amounts of gold in this experiment, this could make the production of such batteries expensive. Penner suggests that a more common metal such as nickel could be used instead of gold.
Sergey Lukavsky