Thursday, April 28, 2016

New battery can be charged more than 200,000 times with no loss of power

Researchers at the University of California Irvine have developed a nanowire-based battery material that can recharged several hundred thousand times without breakdown or loss of energy.

Nanotechnology is described as follows:
Nanotechnology ("nanotech") is manipulation of matter on an atomic, molecular, and supramolecular scale.The earliest, widespread description of nanotechnology[1][2] referred to the particular technological goal of precisely manipulating atoms and molecules for fabrication of macroscale products, also now referred to as molecular nanotechnology.The field may result in many new materials that can be used in such new areas as nanomedicine, nanoelectronics, as well as energy production, and consumer products. Some analysts worry about the toxicity of new nanomaterials and their possible effects on the environment. A nanometer is a metric measure, one billionth of a meter.
A nanowire is thousands of times thinner than a human hair. It is highly conductive of electricity and also has a large area of its surface capable of storage and transfer of electrons. Batteries with the new nanowire could lead to commercial batteries that will have greatly increased lifespans, in computers, smartphones, appliances, cars, and even spacecraft.
Scientists have long been using the nanowires in batteries. However, the wires are very fragile and cannot stand up after repeated charging and recharging or cycling as it is called. In a typical lithium-ion battery they expand and eventually grow brittle and crack. The University of California Irvine (UCI) researchers were able to solve this problem "by coating a gold nanowires in a manganese dioxide shell and encasing the assembly in an electoryte made of a Plexiglas-like gel. The leader of the researchers doctoral candidate Mya Le Thai recharged the electrode up to 200,000 times without any detectable loss of capacity or power. The nanowires did not fracture either.
As well as hard work, the discovery depended in part on accident. According to the senior author of the study, Reginald Penner, chair of the UCI chemistry department: "Mya was playing around, and she coated this whole thing with a very thin gel layer and started to cycle it, She discovered that just by using this gel, she could cycle it hundreds of thousands of times without losing any capacity."Penner noted that usually the devices fail after 5 to 7 thousand cycles at most. The researchers think that the gel gives the metal oxide in the battery more flexibility. Thai said: "The coated electrode holds its shape much better, making it a more reliable option. This research proves that a nanowire-based battery electrode can have a long lifetime and that we can make these kinds of batteries a reality."Much work is being done to improve lithium ion batteries. Using silicon-based rather than a carbon base can double or even triple the storage capacity of the batteries.

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