謝鈺洪

Today wirelessly connected devices are performing an expanding array of applications. Yet how do you power these devices in situations where and when reliable electrical sources are not practically available？ Research from the University of Utahs College of Engineering points to a possible solution in the form of a novel type of battery called a pyroelectrochemical cell （PEC）.

The device is charged by changing temperatures in the surrounding environment， whether its inside a car or aircraft or just under the soil in an agricultural environment. In theory， the PEC could power sensors for IoT? （Internet of Things） applications that would otherwise be impractical to recharge.

The PEC uses a pyroelectric composite material， as the separator in an electrochemical cell. The material consists of porous polyvinylidene fluoride （PVDF） and barium titanate nanoparticles. This materials electrical properties change as its heated or cooled， which decreases or increases the polarization of the pyroelectric separator. Changing temperatures create an electric field inside the cell， pushing ions around and enabling the cell to store energy.

“It stores electricity in whats called an electric double layer， which stores the charge in positive and negative layers of ions.” said lead author Tim Kowalchik， a researcher in Warrens lab. “When you heat and cool the system and youre storing electrochemical energy， youre changing the amount of positive or negative ions that are in those layers.” The cell could produce up to 100 microjoules（焦耳） per square centimeter from a single heating/cooling cycle， which is not much energy， but enough to be useful for IoT purposes， according to the research.

“You want to monitor the condition of your car， the condition of machines， the condition of plants and soil and those kinds of things. Those types of sensors are generally going to be quite a bit lower power than your smartwatch or your phone， which have a display and theyre transmitting a lot of data，” said Roundy， another researcher. “The sensors were talking about might just give periodic updates and they operate autonomously. They dont have an interface or a screen.”

（材料來自Science網(wǎng)站，有刪改）

1. Whats worrying us when it comes to wireless devices？

A. Shockingly wide applications.

B. Unsustainable power support.

C. Poor practical adaptability.

D. Quick power consumption.

2. Whats the main idea of Paragraph 3？

A. The working principle of the PEC.

B. The composition of the PEC.

C. The performance of the new material.

D. The complex design of the device.

3. Whats the function of the electric double layer？

A. To stimulate ions.

B. To produce energy.

C. To preserve electricity.

D. To adjust the system.

4. What can be inferred from what Roundy said？

A. All your devices should be closely watched.

B. Smart watchers sensors are better data senders.

C. The new device is only workable to some sensors.

D. The new devices sensors can transmit big data.

1. B。解析：推理判斷題。材料第一段提到“然而，在實際無法獲得可靠電源的情況下，您如何為這些設(shè)備供電？”由此推斷出目前對于無線設(shè)備我們比較擔心的一個問題是持續(xù)的可靠電力，以此引出材料的話題。B選項“不可持續(xù)的電力支持”與材料相符，故選B。

2. A。解析：主旨大意題。材料第三段有四句話，第一句和第二句談及的是所用的材料PEC及其特性，第三句和第四句介紹該材料如何收集和儲存電力，由此A選項“PEC材料的工作原理”與材料內(nèi)容相符，故選A。

3. C。解析：細節(jié)理解題。材料第四段的第一句提到“它將電儲存在所謂的雙電層中，將電荷儲存在正負離子層中”，由此可知雙電層的作用主要是儲存電力。C選項“儲存電力”與材料內(nèi)容相符，故選C。

4. C。解析：推理判斷題。根據(jù)材料最后一段Roundy所說的話“你想監(jiān)測你的汽車狀況、機器狀況、植物和土壤狀況及諸如此類的東西。這些類型的傳感器通常比有顯示屏的、可以傳輸大量數(shù)據(jù)的智能手表或手機功耗低得多。我們所說的傳感器可能只是定期更新，它們會自主運行。他們沒有界面或屏幕”，以及第二段第二句話“理論上，PEC可以為物聯(lián)網(wǎng)應(yīng)用程序的傳感器供電”可知，研究的新型電池可以用來支撐這類傳感器。C選項“這種新設(shè)備只適用于某些傳感器”與材料相符，故選C。