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Science and technology
科學技術
Battery technology
電池技術
A pile of wood
一堆木頭
An old material may find a new use in batteries
一種古老的原材料可能會在電池上發揮它的新用途。
ON A list of cutting-edge materials for high-tech applications, you might not expect to see wood near the top.
在一個應用于高科技的尖端材料目錄上，看到木材會名列前茅，你可能不會想到。
But an experiment by Teng Li and Liangbing Hu of the University of Maryland may soon put it there.
但是，由馬里蘭大學的李騰和胡良冰所做的一個實驗可能會產生這種意外情況。
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.
根據納米快報的報道，李博士和胡博士已經詳細說明了，在得到允許的情況下，用鈉取代現在制造電池的鋰。再用木材制造某一類電池可能會降低成本。
As any high-school chemist knows, lithium and sodium are chemically similar.
任何一個高中的化學家都知道，鋰和鈉的化學性質很相似。
Sodium ions are, however, five times the size of lithium ions.
然而，鈉離子—在缺少一個電子的前提下，鈉原子帶正電—是鋰離子的五倍大小。
That matters because a battery works by shuttling ions between its anode and its cathode.
這一點很關鍵，因為電池就是通過穿梭于它的陰極和陽極之間的離子來工作的。
The bigger the ion, the more damage this shuttling causes—and the shorter, in consequence, is the battery's life.
離子越大，它的穿梭難度就越大—因此，電池的工作壽命就越短。
Hitherto, that has ruled sodium out as a plausible ingredient of batteries.
到目前為止，作為電池的合理組成部分，鈉早已被排除在外。
But engineers would still like to devise a commercially viable sodium battery, because sodium is much more abundant than lithium.
但是，從商業角度來講，鈉資源遠比鋰資源豐富，所以工程師們仍舊希望能夠發明一種能夠使用的鈉電池。
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，如果使用一種構成電池框架的，更柔韌的材料—以達到延緩電極的目的，這樣是否可以改善有關電極損壞方面的問題。
These frames, which also transmit current to and from the electrodes, are normally made of metal, and are therefore rigid.
這些電池的組成框架也起著在電極之間傳輸電流的作用，它們通常是由金屬材料制成，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.
但是兩位研究者認為，對木材進行適當的處理后，木材也能同樣起到這種傳導的作用，同時，當離子從電極間穿梭時，還能夠更好地增加電極的柔韌性，使之能夠持續地擴張收縮。
To test this idea, they used slivers of wood from yellow pines.
為了測試這種想法，他們從黃松樹干上取了些木條子。
First, they coated these with carbon nanotubes, to improve their conductivity.
首先，他們在這些木條子外面包上了碳納米，以提高它們的導電性。
Then they applied a film of tin to each sliver.
然后，在每個木條子上面涂上了薄薄的錫。
This done, they immersed the slivers in an electrolyte containing sodium ions and put the resulting battery through 400 cycles of discharging and recharging.
完成這些后，研究人員把木條浸在一種含有鈉離子的電解液里，對這種特殊的“電池”進行了四百次的循環充放電。
As a control, they built similar batteries using slivers of copper.
為了便于比較，他們用銅條做成了類似的電池。
The wooden battery was not perfect.
這個木電池并不成功。
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/每小時，但是經過400次不停地充放電后，降到了145毫安時/克。
This, however, was not bad for a prototype, and far better than the copper-framed batteries managed.
然而，對于一個電池雛形來說，結果并不算壞，而且這個結果遠比那個銅電池好得多。
They had an initial capacity of 50 mAH/g.
銅電池的初始容量是50毫安時/克。
That fell to 22 mAH/g after just 100 cycles.
然而僅僅在100次不停地充放電后，就減小到了22毫安時/克。
Wood, then, seems a plausible candidate for battery frames.
所以，木村似乎是電池架構的合理備用材料。
Obviously you are not going to see wooden-framed batteries in your phone or laptop anytime soon.
很明顯，人們要想在自己的手機或筆記本電腦中看到這種木材架構的電池，要很久以后了。
But that was never the plan for Dr Li and Dr Hu.
但是，李博士和胡博士的計劃可不是這樣的。
What their work might lead to is giant sodium-ion batteries for the overnight storage of electricity from solar power stations.
他們的研究結果可能會產生一種巨型鈉電池，用來儲存隔夜的太陽能發電站的電流。
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.
便宜的太陽能儲存是完善太陽能行業目前所急需的—因為與化石燃料相比，現在的太陽能電池已經很便宜了，至少在陽光明媚的天氣是這樣的。
The search for solutions to the solar-energy problem has concentrated on making man-made materials more and more sophisticated.
解決太陽能能源的研究一直專注于制造越來越復雜的人工材料。
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.
如果太陽能行業這個拼圖的完美不是來自于這些時尚的新材料，而來源于人們周圍一種最古老的材料，那將會是一個極大的諷刺。
