December 6, 2011
Period 3 -4 New Technology improves both energy capacity and charge rate in rechargeable batteries
Article Citation * "New technology improves both energy capacity and charge rate in rechargeable batteries." Physorg. N.p., 14 Nov. 2011. Web. 6 Dec. 2011. . Provided by Northwestern University
Summary
* Recently, an electrode for lithium ion batteries that can hold 10 times greater energy than those available in current technology was created by a group of engineers. Despite the limitations they faced to create efficient batteries such as low charge rate and weak energy capacity, they eventually succeed in improving both energy capacity and charge rate in rechargeable batteries by combining two chemical engineering processes. Lithium ions go through a certain chemical process that …show more content…
allows them to recharge the battery. As the energy is consumed, the lithium ions move from the anode to electrolyte and finally to the cathode. As the energy is recharged, they move in the opposite direction, traveling from the cathode. Some of the obstacles engineers faced when developing the efficient energy were that the energy capacity is limited by the charge density and the charge rate is limited by the speed at which lithium ions travel from electrolyte to anode as previously mentioned. First, the energy capacity is limited since the anode, formed with layers of carbon graphene sheets, can only accommodate one lithium atom per six carbon atoms. In order to improve this, scientists have tried to replace carbon atoms with silicon since it accommodates four lithium atoms per silicon. However, silicon expands so dramatically that it results in fragmentation and causes rapid loss of charge capacity. Another main problem that limits the battery efficiency is the speed of a battery’s charge rate. Because the shape of the grapheme sheets is too long and thin, it takes too much time for lithium to travel, causing a traffic jam. Fortunately, the researcher came up with the solution to combat these limitations – they combined the two techniques. By putting together the clusters of silicon between the graphene sheets, they succeeded to allow more lithium atoms to move around while they travel in faster speed. Moreover, the researchers also used the process of oxidation to make small holes in the graphene sheets. This allows the lithium ions to have shortcut in to the anode and therefore reduce the recharging time by 10times.
Reflection
* The article relates to chemistry because several chemical reactions occur during the recharging process of lithium ion batteries.
Lithium ions move from the anode to the electrolyte and finally to cathode when they are being consumed, and travel reversely when being recharged. Lithium ions also go through an oxidation process which allows them to reduce the time it takes to recharge the battery by 10times. I found this article particularly interesting because the newly developed batteries will greatly affect my life. With these efficient batteries, I do not have to worry about my phone running out of batteries and will be able to use my phone without charging it for a week. After reading the article I was curious if it will ever be possible to develop batteries that do not need charging process at all. As technological growth increases, I believe that it might be possible to develop batteries that allow phones to be powered for years. Another curiosity that rose in my mind was that if we can use batteries that can produce energy by chemical reaction, why do we use petroleum and waste natural resources instead of using battery
powers?
Additional Sources
Textbook
Zumdahl, Susan A, and Steven S Zumdahl. Chemistry - seventh edition. Boston, MA: Houhton Mifflin Company, 2007. Print. * During the chemical process, lithium ion move from the anode, the electrode in a galvanic cell at which oxidation occurs, to electrolyte and finally to the cathode, the electrode in a galvanic cell at which reduction occurs.
Online resource
Sorrel, Charlie. "Atom-Thick Graphene Sheets Could Make Great Camera Sensors." gadgetlab. N.p., 11 Oct. 2011. Web. 6 Dec. 2011. . * Graphene, a sheet that forms anode with layers of carbon, is a one-atom-thick sheet of carbon that are densely packed in a honeycomb crystal lattice.