Science and technology

科学技术

Battery technology

电池技术

A pile of wood

一堆木头

An old material may find a new use in batteries

一种古老的原材料可能会在电池上发挥它的新用途。

ON A list of cutting-edge materials for high-tech applications, you might not expect to see wood near the top.

在一个应用于高科技的尖端材料目录上，看到木材会名列前茅，你可能不会想到。

But an experiment by Teng Li and Liangbing Hu of the University of Maryland may soon put it there.

但是，由马里兰大学的李腾和胡良冰所做的一个实验可能会产生这种意外情况。

For Dr Li and Dr Hu, writing in Nano Letters, have just described how wood might be used to make one class of batteries cheaper by permitting the lithium now employed in them to be replaced with sodium.

根据纳米快报的报道，李博士和胡博士已经详细说明了，在得到允许的情况下，用钠取代现在制造电池的锂。再用木材制造某一类电池可能会降低成本。

As any high-school chemist knows, lithium and sodium are chemically similar.

任何一个高中的化学家都知道，锂和钠的化学性质很相似。

Sodium ions are, however, five times the size of lithium ions.

然而，钠离子—在缺少一个电子的前提下，钠原子带正电—是锂离子的五倍大小。

That matters because a battery works by shuttling ions between its anode and its cathode.

这一点很关键，因为电池就是通过穿梭于它的阴极和阳极之间的离子来工作的。

The bigger the ion, the more damage this shuttling causes—and the shorter, in consequence, is the battery's life.

离子越大，它的穿梭难度就越大—因此，电池的工作寿命就越短。

Hitherto, that has ruled sodium out as a plausible ingredient of batteries.

到目前为止，作为电池的合理组成部分，钠早已被排除在外。

But engineers would still like to devise a commercially viable sodium battery, because sodium is much more abundant than lithium.

但是，从商业角度来讲，钠资源远比锂资源丰富，所以工程师们仍旧希望能够发明一种能够使用的钠电池。

Dr Li and Dr Hu wondered if the problem of electrode damage might be ameliorated by using a more pliant material for the frames on which the electrodes are suspended.

李博士和胡博士想弄清楚，如果使用一种构成电池框架的，更柔韧的材料—以达到延缓电极的目的，这样是否可以改善有关电极损坏方面的问题。

These frames, which also transmit current to and from the electrodes, are normally made of metal, and are therefore rigid.

这些电池的组成框架也起着在电极之间传输电流的作用，它们通常是由金属材料制成，因此硬度很高。

But the two researchers reckoned that suitably treated wood could do the job of conduction equally well while providing more yielding support for an electrode that was continually expanding and contracting as ions moved in and out of it.

但是两位研究者认为，对木材进行适当的处理后，木材也能同样起到这种传导的作用，同时，当离子从电极间穿梭时，还能够更好地增加电极的柔韧性，使之能够持续地扩张收缩。

To test this idea, they used slivers of wood from yellow pines.

为了测试这种想法，他们从黄松树干上取了些木条子。

First, they coated these with carbon nanotubes, to improve their conductivity.

首先，他们在这些木条子外面包上了碳纳米，以提高它们的导电性。

Then they applied a film of tin to each sliver.

然后，在每个木条子上面涂上了薄薄的锡。

This done, they immersed the slivers in an electrolyte containing sodium ions and put the resulting battery through 400 cycles of discharging and recharging.

完成这些后，研究人员把木条浸在一种含有钠离子的电解液里，对这种特殊的“电池”进行了四百次的循环充放电。

As a control, they built similar batteries using slivers of copper.

为了便于比较，他们用铜条做成了类似的电池。

The wooden battery was not perfect.

这个木电池并不成功。

It's initial capacity was 339 milliamp hours per gram, but that fell to 145 mAH/g over the course of the 400 cycles.

它的初始容量是339毫安/每小时，但是经过400次不停地充放电后，降到了145毫安时/克。

This, however, was not bad for a prototype, and far better than the copper-framed batteries managed.

然而，对于一个电池雏形来说，结果并不算坏，而且这个结果远比那个铜电池好得多。

They had an initial capacity of 50 mAH/g.

铜电池的初始容量是50毫安时/克。

That fell to 22 mAH/g after just 100 cycles.

然而仅仅在100次不停地充放电后，就减小到了22毫安时/克。

Wood, then, seems a plausible candidate for battery frames.

所以，木村似乎是电池架构的合理备用材料。

Obviously you are not going to see wooden-framed batteries in your phone or laptop anytime soon.

很明显，人们要想在自己的手机或笔记本电脑中看到这种木材架构的电池，要很久以后了。

But that was never the plan for Dr Li and Dr Hu.

但是，李博士和胡博士的计划可不是这样的。英语六级几分算过

What their work might lead to is giant sodium-ion batteries for the overnight storage of electricity from solar power stations.

他们的研究结果可能会产生一种巨型钠电池，用来储存隔夜的太阳能发电站的电流。

Cheap storage is the missing part of the solar-energy jigsaw—for solar cells themselves are now cheap enough to compete with fossil fuels, in sunny climes at least.

便宜的太阳能储存是完善太阳能行业目前所急需的—因为与化石燃料相比，现在的太阳能电池已经很便宜了，至少在阳光明媚的天气是这样的。

The search for solutions to the solar-energy problem has concentrated on making man-made materials more and more sophisticated.

解决太阳能能源的研究一直专注于制造越来越复杂的人工材料。

It would be a delicious irony if the jigsaw was completed not by one of these snazzy new substances but by one of the oldest materials around.

如果太阳能行业这个拼图的完美不是来自于这些时尚的新材料，而来源于人们周围一种最古老的材料，那将会是一个极大的讽刺。