Lithium-ion technology is bringing us closer to solving energy and transport problems, finds Bruno
Bottled Lightning: Superbatteries, Electric Cars, and the New Lithium Economy
When, in 1801, Alessandro Volta unveiled his 'electric pile' gadget to Napoleon Bonaparte, he could not have imagined that, two centuries later, his invention would be central to human life. His primitive electrical cell of zinc and silver electrodes separated by a brine-soaked felt led to the compact electrochemical power source that dominates modern consumer electronics — the lithium battery. In Bottled Lightning, science journalist Seth Fletcher explains how lithium batteries work and describes the research steps that have led to their ubiquity. The mobile electronics market is booming, producing billions of units a year and billions of dollars in profits. And new challenges for lithium batteries are opening up in green energy. Fletcher describes the fierce competition to develop the next generation of lithium batteries, but could have given more people their due for the existing technology. Decreasing oil resources and concerns about climate change necessitate greater use of alternative energy sources, such as solar and wind, and the replacement of polluting internal-combustion cars with hybrid vehicles, plug -in hybrid vehicles and, ultimately, fully electric vehicles. As the sun does not always shine and the wind does not blow on command, the success of these renewable sources depends on efficient storage. Electrochemical batteries, lithium ones in particular, are the best option, converting stored chemical energy into electricity with high efficiency and without toxic emissions. As yet, lithium batteries do not meet the technical requirements of hybrid or electric vehicles. The challenge is to move beyond the present chemistry to produce batteries that are safer, cheaper and have greater energy density . This will not be easy. But the ecological, economical and political rewards are so great that many countries are directing tremendous amounts of funding towards research and development in battery technology. The result, as Fletcher puts it, is that in the past decade, “advanced-battery start- ups started popping up like mushrooms after a spring rain”. This intense activity has also given rise to a series of patent conflicts and legal battles over priority, which Fletcher aptly calls “lithium wars” . He focuses on the many-sided battle for the patent of the lithium-battery cathode material — a lithium-iron phosphate with an olivine crystal structure that is one of the most promising advanced electrode materials. As he says, such clashes are not new: patent disputes and get-rich-quick hype have dogged the battery business since its inception. Fortunately, the battery-science community has avoided this bad atmosphere and continues to make progress. As well as lithium-iron phosphate, other innovative materials have been used for the three main battery components of anode, cathode and electrolyte. But there is still no lithium battery light enough to power a small electric car over a reasonable distance on a single charge. Urgently needed are 'superbatteries' with energy densities at least two or three times higher than at present. The most promising candidates are lithium–sulphur and lithium–air batteries, which in principle should be able to store 5–10 times the energy of today's cells. These are conceptually simple, but their implementation has been stalled by a series of apparently insurmountable hurdles: the high solubility of the ( polysulphide) discharge products; the high resistance of the electrode materials in the case of lithium sulphur; the slow kinetics of the oxygen electrode; and the instability of the lithium anode in the case of lithium air. There have been breakthroughs in the past few years with the development of advanced sulphur electrode nanomorphologies, the clarification of the oxygen reduction process, the use of appropriate catalysts for promoting its evolution, and the stabilization of the lithium electrode by covering it with protective films. The road to applications is still long, but the race for the electric car has started. Many car makers are seeking joint ventures with battery manufacturers to pursue the Japanese frontrunners who, having won their early bet on hybrids, are still the major players in electric vehicles. With demand for lithium set to grow, some question whether Earth's crust contains enough of the ｍｅｔａl to sustain its use in vehicles. Fletcher cleverly analyses the debate and gives vivid deｓｃｒｉｐｔions of his trips to Bolivia and Chile to visit the two main salt deposits that, together with a third in Argentina, are the richest sources of lithium carbonate. The reserves could last for centuries, so there will be enough lithium to fill up our tanks even in the improbable case of all cars becoming hybrid or electric. Bottled Lightning is a gripping introduction to this sophisticated technology and its place in our society. My only criticism is that Fletcher fails to credit the group of US and European scientists, including Don W. Murphy, Michel Armand and myself, who in the early 1980s developed the lithium-ion battery concept. The field then fell silent for more than ten years, until the Japanese company Sony optimized the idea for the first commercial lithium-ion battery in the early 1990s. As Fletcher notes, plenty has happened since. 锂电池特辑2: 用电池供电的大楼 加州大学的工程学院大楼用电池供电 用电池供电的建筑 在温斯顿世界能量公司CEO的慷慨资助下,工程学院的大楼要用稀土锂电池供电了 这是革新的一步,温斯顿世界能量的创建者,董事长兼CEO向加州大学捐赠了价值250万美 元的稀土锂电池,为河滨分校的伯恩斯工程学院的一楼供电.作为回报,学院将工程学院 的大楼更名为温斯顿钟氏大楼
undefined 当然，这种“革命性”的产品也不乏批评者。麦克斯威尔科技公司的运输技术开发副总 吉姆?米勒说：埃斯托公司的技术必须要解决的问题是它脆弱的结构如何能够承 受汽车严酷的使用环境。我们还是对这家公司的新技术一些信心，就像他们说的，这是 他们的第一次尝试，他们会让这项技术“符合它所承诺的功能”--我们能看到这一天吗 ？undefined smallfat If relying on sunlight and downhill routes in Venturi's uber-green Eclectic doesn't exactly sound feasible for your everyday (and night) errands, and your ultraportable's five hours of battery life just isn't where you think it should be, EEStor is hoping to remedy those issues -- along with basically every other battery-related quandary -- in one fell swoop. In another case of "this just can't be for realz," an elusive Texas company is coming clean about what's been happening in its labs of late, and the proclamations are nothing short of sensational. The firm boldly states that its one of a kind system, a "battery-ultracapacitor hybrid based on barium- titanate powders, will dramatically outperform the best lithium-ion batteries on the market in terms of energy density, price, charge time, and safety." Moreover, this miracle-working solution is said to produce "ten times" the power of lead-acid batteries at half the cost, sans the need for "toxic materials or chemicals." Additionally, EEStor is hoping to have its Electrical Energy Storage Unit (EESU) powering the wheels of Toronto-based ZENN Motor vehicles, and if "estimates" are to be believed, it will only take about $9 worth of electricity for an EESU-propelled car to travel 500 miles, compared to nearly $60 in gasoline. Of course, such a "breakthrough" product is bound to have its fair share of naysayers, and Jim Miller, vice president of advanced transportation technologies at Maxwell Technologies, is indeed skeptical that EEStor's technology will be able to withstand the unique pressures that a vehicle would place on the "brittle" structure. But we've got to give credit to the company's vow to veer clear of hype, as it notes that this is just the first time it has come forward to intro the technology, and maintains that it will "meet all of its claims" -- guess we' ll see about that, eh?
新型电极实现锂电池2分钟完成快速充电
在大部分的现代小玩意中，电池都是必要的部件，随着应用于汽车和电网，预计电池充 当的角色更为扩展。但电池也有一些局限，它无法象超级电容那样快速充电，而且随着 时间的推移，它的容量会衰减。为了克服这些限制，科学家们试验了各种各样的材料， 有时候确实也获得了令人注目的成功。周末，一份论文发表了一种可以实现电池快速充 电的技术。这种技术使用了与先前不同的方法和技术，能用于锂基和镍基电池。 先前的方法主要针对锂电池，专注于克服电池的充电速度：离子能以多快的速度在电池 材料中运动。研究者过去都是通过改变锂电池的主要原料——磷酸铁锂（LiFePO4）— —的结构来实现锂离子在电池材料中的快速传递的。而作者则通过提高电极的接触面， 使其可以与离子进行快速的电荷交换，实现电池的快速充电。 新的方法采用了完全不同的技术路线，同样获得了快速充电的效果。来自伊利诺斯大学 的论文作者们并不关心离子在电池材料中的运动速度，他们致力于减少离子运动到电极 上所行走的距离。他们指出，离子的运行时间与距离的平方成正比，所以减少距离可以 获得引人注目的效果。为减少这段距离，他们专注于开发一种结构精密的阴极材料。 他们的制作过程其实相当简单，适合进行大规模生产。开始的时候，他们采用聚苯乙烯 小球汇聚的球团，通过调整这些小球的大小（他们选用直径在1.8微米到466纳米之间的 小球），可以调整电极的空间特性。当小球的排列符合要求之后，将获得一种类似猫眼 石（一种硅元素的结构）的结构，用加强材料将这种排列结构固定下来。然后，在猫眼 石结构表面用电沉积法镀上一层镍膜，之后把猫眼石蚀刻掉，再经过电解抛光，增加这 些镍膜空隙度。 当整个过程完成后，空隙度达到94%，刚好低于96%的极限水平。这样一来，作者们就获 得了一团包含很多空间的镍丝网。 这些空间将用来填充电池材料，可以是镍金属氢化物，也可以是掺杂锂的二氧化锰。作 者称这种布局具备三大优点：电镀网孔有利于离子的快速运动，离子到达电极的距离缩 短，电极导电性提高。这些优点的叠加使得做出来的电池在充放电速度上可以与超级电 容相媲美。 对于镍氢电池，这种电池可以在2.7秒的时间内放出标准电量的75%，而充满90%的电量 只需要20秒。按这样的强度经过100次充放循环，电池性能还可以保持稳定。锂电池表 现稍微差一点，但也相当了不起。标准电量的75%可以实现高速放电，而经过1000次循 环后，还能保持三分之一的存储能力。 完全用这种电极制作的锂电池，能做到1分钟充满75%的电量，充满90%的电量只需要2分 钟。 作者称这种技术还有其他一些优异的特性，可以实现大规模生产，除了应用于上文提到 的锂材料和镍材料，它可以应用于更多的电池材料。先前的磷酸铁锂材料也能结合采用 这种技术。通过专门设计，使电池材料与这种电极匹配，可以进一步提升电池性能。 当然，使用这么高的速度给电池充电，我们最终不可避免将面临提供大电流的问题。对 于类似手机上使用的小电池来说，这样快速充电表现优异，但是如果想用于对电动汽车 快速充电，那将是一项挑战。 kentwin Batteries are an essential part of most modern gadgets, and their role is expected to expand as they're incorporated into vehicles and the electric grid itself. But batteries can't move charge as quickly as some competing devices like supercapacitors, and their performance tends to degrade significantly with time. That has sent lots of materials science types into the lab, trying to find ways to push back these limits, sometimes with notable success. Over the weekend, there was another report on a technology that enables fast battery charging. The good news is that it uses a completely different approach and technology than the previous effort, and can work with both lithium- and nickel-based batteries.
The previous work was lithium-specific, and focused on one limit to a battery's recharge rate: how quickly the lithium ions could move within the battery material. By providing greater access to the electrodes, the authors allowed more ions to quickly exchange charge, resulting in a battery with a prodigious charging rate. The researchers increased lithium's transport within the battery by changing the structure of the battery's primary material, LiFePO4.
The new work also gets fast charges, but by a rather different route. The authors, from the University of Illinois, don't focus on the speed of the lithium ions in the battery; instead, they attempt to reduce the distance the ions have to travel before reaching an electrode. As they point out, the time involved in lithium diffusion increases with the square of the distance travelled, so cutting that down can have a very dramatic effect. To reduce this distance, they focus on creating a carefully structured cathode .
The process by which they do this is fairly simple, and lends itself to mass production. They started with a collection of spherical polystyrene pellets . By adjusting the size of these pellets (they used 1.8181;m and 466nm pellets), they could adjust the spacing of the electrode features. Once the spheres were packed in place, a layer of opal (a form of silica) was formed on top of them, locking the pattern in place with a more robust material. After that, a layer of nickel was electrodeposited on the opal, which was then etched away. The porosity of the nickel layer was then increased using electropolishing.
When the process was done, the porosity—a measure of the empty space in the structure—was about 94 percent, just below the theoretical limit of 96 percent. The authors were left with a nickel wire mesh that was mostly empty space.
Into these voids went the battery material, either nickel-ｍｅｔａl hydride (NiMH) or a lithium-treated manganese dioxide. The arrangement provides three major advantages, according to the authors: an electrolyte pore network that enables rapid ion transport, a short diffusion distance for the ions to meet the electrodes, and an electrode with high electron conductivity. All of these make for a battery that acts a lot like a supercapacitor when it comes to charge/discharge rates.
With the NiMH battery material, the electrodes could deliver 75 percent of the normal capacity of the battery in 2.7 seconds; it only took 20 seconds to recharge it to 90 percent of its capacity, and these values were stable for 100 charge/discharge cycles. The lithium material didn't work quite as well, but was still impressive. At high rates of discharge, it could handle 75 percent of its normal capacity, and still stored a third of its regular capacity when discharged at over a thousand times the normal rate.
A full-scale lithium battery made with the electrode could be charged to 75 percent within a minute, and hit 90 percent within two minutes.
There are a few nice features of this work. As the authors noted, the electrodes are created using techniques that can scale to mass production, and the electrodes themselves could work with a variety of battery materials , such as the lithium and nickel used here. It may also be possible to merge them with the LiFePO4 used in the earlier work. A fully integrated system, with materials designed to work specifically with these electrodes, could increase their performance even further.
Of course, that ultimately pushes us up against the issue of supplying sufficient current in the short time frames needed to charge the battery this fast. It might work great for a small battery, like a cell phone, but could create challenges if we're looking to create a fast-charge electric car.
一种新奈米结构让锂电池能够更快的充电 新技术让锂电池的充电变得更加快捷 伊利诺伊大学的一个研究团队拥有一项可能会对电动汽车和其它电子设备有深远影响的 技术。 该团队由材料工程科学领域的保罗?布劳恩教授领导，他们发现了让锂电池快速 充电的技术，在手机、笔记本电脑以及植入式心脏除颤器等电子设备中锂电池得到广泛 应用。锂电池也用于电动汽车，一次充电在家中需要一个晚上的时间，就是在电动车充 电站也需一个小时来完成充电。 布劳恩的研究成果发表在《自然-纳米技术》在线版上，保罗表示电动汽车的充电时间 与加满一油箱汽油的时间相当。像手机这类较小的电子元件充电时间不超过一分钟。“ 我们实验室的电池组能够在数十秒中完成充电”他说。 电池充电时，能量从阴极移至阳极。当电池释放电能或放电时，能量以相反的方向迁移 ，从阳极移至阴极。保罗的团队为电池的阴极设计了一种三维的奈米结构能使得电池的 充电速度比传统的电池快的多。 传统的锂离子以及金属氢化物镍蓄电池中所含有的活性物质被放置在一个薄膜中。这个 薄膜为了让电池能够更快地充电，但是这以其最终会明显退化为代价。因为薄膜很薄， 它不能存储很多能量。这种低密度的能量导致它快速退化。 布劳恩的发明是在这个薄膜外包裹一种三维结构使得它既能快速的充电，并且又能存储 更多的能量。这种三维结构是利用微小的球体制作成薄膜的外涂层。球体之间的空隙用 金属填充。它们随后融合成可渗透海绵状的表面。接下来，那些小孔变大并且该结构覆 盖了薄膜。 布劳恩表示该奈米结构不能避免退化，但是该处理会延迟退化，因为它的效率是传统电 池的10倍。他还希望这种高效能够在低温的环境中良好的运行，虽然他的团队还没有在 此环境中开展研究。 他表示，想让电动汽车的电池充电时间与加满一油箱汽油的时间相当的速度则需要对现 行的基础设施结构进行改造。充电站需要提供足够的电能，但是保罗表示最终需要有相 应的激励机制来促进该技术的发展。 虽然该奈米结构提高了电池20-30百分点的储电能力，布劳恩表示该结构最显著的特点 是提高了充电速率。 布劳恩团队对该奈米结构开展了两年的研究。他表示该奈米结构应用于电池的阴极，下 一步是促进电池的阳极，并促进电池的储电能力。 遥探 New Structure Allows Lithium Ion Batteries to Get a Quicker Charge A new technology could create a much more rapid charging time for lithium ion batteries A research group at the University of Illinois has developed technology that may have lasting implications for electric vehicles (EVs) and other electronics. The group, led by Paul Braun, a professor of material sciences and engineering, has come up with technology that creates a much more rapid charging time for lithium-ion batteries, which power electronics like cellphones, laptops and defibrillators. Lithium-ion batteries also power EVs , which can take all night to charge at home and up to an hour to charge at EV stations. Braun's findings, published last week in an online version of the journal Nature Nanotechnology, could lead to an EV charging time comparable to that for filling a tank of gas. Smaller objects like cell phones could charge in well under a minute, Braun said. "We have batteries in the lab that can charge in tens of seconds," he said. When a battery charges, energy moves between its cathode and anode. When a battery powers a product, or discharges, energy travels the opposite way, between its anode and cathode. Braun's group came up with a three- dimensional nanostructure for the battery cathode that allows its batteries to charge at a much faster rate than conventional batteries. Conventional lithium-ion or nickel ｍｅｔａl hydride rechargeable batteries contain active material that is placed into a thin film. The thin film allows batteries to charge and recharge quickly, but at the cost of significant degrading over time. Because it's thin, the film doesn't allow for much energy storage. This lack of density causes the rapid degrading. Braun's invention wraps the thin film around a 3-D structure that allows greater energy storage capacity while still rapidly charging and recharging. The 3-D structure is assembled by coating the surface with tiny spheres. The space between the spheres gets filled with ｍｅｔａl. Both are then melted together, leaving a porous, sponge-like surface. Next, the pores get enlarged and the structure is coated with the thin film. The nanostructure isn't immune to degrading, but this process is prolonged because its efficiency is 10 times greater than conventional batteries, Braun said. He also expects this greater efficiency will allow EV batteries to work better in cold temperatures, although his group hasn't conducted studies to verify this yet. Getting EV batteries to charge as fast as it takes to fill a tank of gas requires a different infrastructure than what exists today, he said. Charging stations will need to offer sufficient power, but Braun said developing technology should eventually create an incentive for it. Although the nanostructure makes the batteries 20 to 30 percent denser, Braun said the biggest improvement is the rapidity of the charging. Braun's group worked for about two years on the nanostructure. Since the nanostructure is applied to a battery's cathode, he said, the next step is to study improving the anode, along with further increasing battery density.