高速充电手机电池问世 充满电只需10秒(图)

麻省理工工程师研制的新型电池材料

　　新浪科技讯北京时间3月12日消息，据国外媒体报道，美国科学家研制出一种具有革命性的手机电池，与充电时间需要几个小时的普通电池相比，这种电池只需10秒钟便可完成充电过程。

　　科学家表示，新电池的充电速度是传统电池的100倍，2到3年内便可用在手机、笔记本电脑、iPod、数码摄像机和照相机上。此外，同样的技术也可大大缩短电动汽车的充电时间，能够与传统汽车的加满时间不相上下，进而扫除绿色环保汽车面临的其中一个最大障碍。

　　新型快充电池是麻省理工学院工程师共同努力的结晶。研究小组表示，他们的发明所使用的材料已经被用于电池制造，实现大批量生产并非难事。新型快充电池立基于传统的已被广泛用于摄像机、照相机、手机和笔记本的锂离子充电电池。锂电池之所以能够用于这些便携式设备是因为它们能够在很小的空间储存大量电量。然而，锂电池的充电速度还是相对较慢。对于任何用户来说，如果头天晚上忘记给手机充电，一定会给第二天的使用带来不小麻烦。

　　负责设计新电池的格布兰德·塞达尔(Gerbrand Cedar)博士说：“电动汽车电池可存储相当多电量，你能够以时速55英里(约合每小时88公里)的速度开上很长时间，但电池的功率仍比较低，以致无法迅速加速。”根据《自然》杂志的报道，塞达尔及其同事找到了一种加快这一过程的方式。传统锂电池拥有两个电极，一个由锂制成，另一个由碳制成，两个电极被淹没于电解液中。充电时，锂离子——或者说带正电的原子——从锂电极流向碳电极；放电时，锂离子则以相反方向流动。

　　电池充电或放电速度慢是因为锂离子从一个电极流向另一个电极需要一定时间。研究人员将由锂铁磷酸盐制成的传统电极表面结构加以改进，让锂离子的释放和吸入速度大大提高，是原来的100倍。利用这种新技术制成的电池原型只需10到20秒便可完成充电或放电过程。相比之下，体积相当的普通电池则需要6分钟才能完成充电。

　　与其它电池材料有所不同的是，新材料不会随着重复充电和放电老化。科学家表示，充电速度更快的电池可连续使用2年或者3年。塞达尔说：“充放电时间以秒而不是以小时计算的电池可能为新的技术应用打开一扇门，同时也将改变人们的生活方式。”此外，这项技术也可用于研制新一代体积更小、重量更轻的电池，让手机和笔记本电池的个头只有一张信用卡大小。

　　新型快充电池将受到便携式电子设备用户的青睐，他们不必提醒自己在头天晚上充电，除此之外，这项新发明也将孕育新一代电动汽车。相对于现有的充电时间需要大约8小时的电池而言，体积更大的电动汽车电池只需5分钟便可完成充电。这样一来，电动汽车用户便可放心大胆地进行远距离行使，而不必担心电量问题，只要能找到服务站，他们便可在短短几分钟内为汽车充满电，就像驾驶汽油或柴油汽车的人一样。(孝文）

Re-engineered battery material could lead to rapid recharging of many devices

Beltway for electrical energy solves long-standing problem

Elizabeth A. Thomson, News Office
March 11, 2009

MIT engineers have created a kind of beltway that allows for the rapid transit of electrical energy through a well-known battery material, an advance that could usher in smaller, lighter batteries -- for cell phones and other devices -- that could recharge in seconds rather than hours.

The work could also allow for the quick recharging of batteries in electric cars, although that particular application would be limited by the amount of power available to a homeowner through the electric grid.

The work, led by Gerbrand Ceder, the Richard P. Simmons Professor of Materials Science and Engineering, is reported in the March 12 issue of Nature. Because the material involved is not new -- the researchers have simply changed the way they make it -- Ceder believes the work could make it into the marketplace within two to three years.

State-of-the-art lithium rechargeable batteries have very high energy densities -- they are good at storing large amounts of charge. The tradeoff is that they have relatively slow power rates -- they are sluggish at gaining and discharging that energy. Consider current batteries for electric cars. "They have a lot of energy, so you can drive at 55 mph for a long time, but the power is low. You can't accelerate quickly," Ceder said.

Why the slow power rates? Traditionally, scientists have thought that the lithium ions responsible, along with electrons, for carrying charge across the battery simply move too slowly through the material.

About five years ago, however, Ceder and colleagues made a surprising discovery. Computer calculations of a well-known battery material, lithium iron phosphate, predicted that the material's lithium ions should actually be moving extremely quickly.

"If transport of the lithium ions was so fast, something else had to be the problem," Ceder said.

Further calculations showed that lithium ions can indeed move very quickly into the material but only through tunnels accessed from the surface. If a lithium ion at the surface is directly in front of a tunnel entrance, there's no problem: it proceeds efficiently into the tunnel. But if the ion isn't directly in front, it is prevented from reaching the tunnel entrance because it cannot move to access that entrance.

Ceder and Byoungwoo Kang, a graduate student in materials science and engineering, devised a way around the problem by creating a new surface structure that does allow the lithium ions to move quickly around the outside of the material, much like a beltway around a city. When an ion traveling along this beltway reaches a tunnel, it is instantly diverted into it. Kang is a coauthor of the Nature paper.

Using their new processing technique, the two went on to make a small battery that could be fully charged or discharged in 10 to 20 seconds (it takes six minutes to fully charge or discharge a cell made from the unprocessed material).

Ceder notes that further tests showed that unlike other battery materials, the new material does not degrade as much when repeatedly charged and recharged. This could lead to smaller, lighter batteries, because less material is needed for the same result.

"The ability to charge and discharge batteries in a matter of seconds rather than hours may open up new technological applications and induce lifestyle changes," Ceder and Kang conclude in their Nature paper.

This work was supported by the National Science Foundation through the Materials Research Science and Engineering Centers program and the Batteries for Advanced Transportation Program of the U.S. Department of Energy. It has been licensed by two companies.