December 6, 2011
Period 3 -4
New Technology improves both energy capacity and charge rate in rechargeable batteries
* "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 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,...