[科技] 電池再進化，新一代產電的選擇！20191103 Science

New charging technique could power an electric car battery in 10 minutes

新的電池充電技術，將可以在十分鐘內讓電動車充飽電

By Robert F. Service

Tesla and other car companies are selling a record number of electric vehicles (EVs). But even at souped-up “supercharger” stations, the cars still require up to 50 minutes to top off their batteries. A new advance may change that.

近年來，特斯拉與其他汽車公司，創造了許多電動車的銷售佳績。但是，即使使用特斯拉公司所搭配的“超級充電”系統，仍然需要使用約50分鐘才能加一輛車充滿電。但是，最近的技術突破也許會改變這個時間限制。

One strategy for boosting battery charging speeds has been to raise the battery temperature during charging, which accelerates the chemical reactions inside the battery. But keeping batteries at high temperatures can cause components to break down quickly.

其中一個加快充電時間的方式是提供電池充電時的速度，這樣會加快在電池內部的化學反應。然而，寶石電池在高的溫度下，會使得電池的各部件快速地消耗。

Now, researchers report they can prevent this breakdown, and allow fast charging, if the heat is added just for short periods. By heating up a charging device to 60°C for just 10 minutes, they were able to speed the incorporation of lithium ions into layers of graphite that make up the anode (as shown in the above artist’s representation), the key step in recharging the battery. If scaled up, this would allow them to add 320 kilometers in driving range to conventional lithium-ion batteries, they report today in Joule. The heated batteries were also stable, able to go through 1700 charge-discharge cycles with little degradation.

現在，研究人員宣稱他們可以只在短暫的時間內升高溫度，就可以避免這些零件的消耗，因此可以加快充電的速度。藉著加熱電池到攝氏六十度，維持十分鐘的時間，研究然完可以加速充電時最重要的步驟 - 將鋰離子嵌合到構成陽極的石墨層內（就如同下圖所示）。

將這個實驗放大的話，將能夠增加傳統電池320公里的續航力。這個加熱的電池依舊可以保持穩定，在經過1700次的充電的情況下，電池仍然只有輕微的損耗。

Next up, the researchers are looking to cut their charging time in half, adding enough juice to power an EV in just 5 minutes.

接著，這些研究人員希望能夠把充電的時間減半，在五分鐘之內將足夠的電力充飽一台電動車。

原文出處： https://www.sciencemag.org/news/2019/10/new-charging-technique-could-power-electric-car-battery-10-minutes

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This ‘two-faced’ membrane can create electricity—from nothing but salty water

新的“雙面”薄膜系統將可以從鹽水中獲取電力

By Frankie Schembri

Imagine being stuffed into a crowded train car and noticing a less crowded one just down the platform. You’d probably want to move over as soon as possible. Particles that follow this balancing act—known as osmosis—spontaneously move from an area of high concentration to one of low concentration. Now, scientists have used this tendency to create a power-producing membrane that can harvest electric current from nothing but salty water.

想像一下，如果你身處在一班壅擠的電車中，發現在月台的另外一側，有一台比較沒有這麼擠的電車，你可能會很想進快的移動到那輛電車上。粒子也遵守著這樣的平衡守則 -滲透壓平衡，粒子會自發性地從高密度的地方往低密度的地方移動。現在，科學家利用這樣的趨勢，製造了一個薄膜系統以從鹽水中獲取電力。

When ionic salts, made of bundles positively and negatively charged particles, dissolve in water, the bundles break apart, leaving positively and negatively charged particles free to participate in osmosis. By placing charged, thin membranes in between salty water and freshwater, scientists can create an expressway for the flowing particles, generating electric current. But these membranes are often expensive to manufacture and they tend to get leaky over time. That lets particles pass back through in the wrong direction, cutting into how much electricity they can produce.

當鹽離子，由正電與負電粒子所建構的結晶，溶解在水中時，這些鍵結會斷裂，使得帶著正負電的離子自由地在水中游離達成滲透平衡。藉由在鹽水與淡水中放置一片帶著電荷的薄膜，科學家建立為這些帶電粒子建造了一條快速通道，當離子移動時，就會產生電力。然而，這些薄膜通常在製造上需要大筆資金，而且容易隨著時間而滲漏，而使得離子又再度回到薄膜的另一側而減少可以產生的電力。

Now, researchers have developed a new kind of gatekeeper—a “two-faced” membrane that has different properties on either side, from the size of the pores to the charge of the membrane itself. This encourages a steady flow of charged particles from one side to the other while preventing them from drifting back in the wrong direction. These so-called Janus membranes, named after the ancient Roman god of gates and passages, can also be manufactured to have different-size pores and hold different charges, allowing them to accept different kinds of particles.

如今，科學家發展出新的一種雙面的薄膜，在這個薄膜的兩面，有著不同的孔徑大小以及帶電荷的狀態。這使得帶著電荷得離子只會從一側固定的移動到另一側，而不會留回原來的方向。

這個稱為“亞努斯”（希臘神話中，看守門的神，有著兩個臉孔面向前後）的薄膜，可以經由設計來產生不同大小的孔徑，也可以帶有不同的電荷，使得它可以通透不同種類的粒子。

The researchers tested their Janus membranes with salty sea water on one side and fresh river water on the other. They found the devices were able to convert 35.7% of the chemical energy stored in the salty water into useable electricity. That’s as efficient as most wind turbines and higher than most solar cells, they report today in Science Advances.

研究人員在Science Advances期刊中發表了利用在亞努斯膜的一側放置淡水，另一側置入鹽水來測試，發現這個裝置可以轉換約35.7%的化學能成為可用的電力。這樣的效能比大多數的太陽能板高出許多，大約等於風力發電的風車裝置。

Next, the researchers plan to build larger membranes and see whether they can withstand the conditions of real sea and river water. If the membrane performs as well in “the wild,” the new membranes could be used to power remote communities with no other sources of renewable energy in just a few years, the researchers say. That suggests that when it comes to harvesting power from moving particles, being a little two-faced is a good thing.

下一步，研究人員計畫建造大型的亞努斯膜，想看看他們是否也能利用這個裝置，在河的出口與海的交接處，產生同樣的效能。研究人員表示，如果這個系統在“野外”也能夠用作，亞努斯膜系統也許可以在未來的幾年內，讓沒有其他再生性能源資源的沿海國家利用來產生電力。

原文出處：https://www.sciencemag.org/news/2018/10/two-faced-membrane-can-create-electricity-nothing-salty-water

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＊在人口越來越多，對於電子產品的依靠日益增加的今日，如何有效率的產生能源而不污然環境，嚴然是人類生存的一大挑戰。這兩個新的技術改良，對人類使用電力的方式，都有很大程度的影響。鋰電池的發明，讓原來龐大的電池大幅的縮小了體積，再加上可以攜帶大量的電力，已經是人類生活中不可或缺的物件。然而充電的速度仍然還有進步的空間。這次的研究，使得充電的速度大幅的提升，唯一的考量可能是，在其他家用產品或是手機上，加熱到攝氏六十度也許不是一個理想的選項，但是在為車輛充電，只要周圍的零件不會受到溫度的影響，也許會是未來推廣電動車的一大賣點。再搭配上第二個研究，能夠利用大自然中的淡水與海水，創造出電力，也許會是一個有潛力的再生能源來源。不過站在生物學者的角度來看，即使真的能夠製造出足夠隔離河與海的薄膜，這個薄膜能否抵抗河水的壓力（可能得做成像水壩一樣），是否會造成附近區域洪水，對於周邊生態的改變，將鹽離子強制的送到淡水中，會導致周邊生態系的大幅改變，這些都將會是利用這個技術的一大挑戰。但是不可諱言的，也許利用一些隔離設施來循環淡水與海水，也許能製造出一個產生一定電力的系統，未來也許真的有機會實現。