The Kynix Blog - Battery

(In a new concept for battery cathodes, nanometer-scale particles made of lithium and oxygen compounds (depicted in red and white) are embedded in a sponge-like lattice (yellow) of cobalt oxide, which keeps them stable.)  Engineers from MIT propose that a new lithium-oxygen battery material could be packaged in batteries that are very similar to conventional sealed batteries yet provide much more energy for their weight. Lithium-air batteries are considered highly promising technologies for electric cars and portable electronic devices because of their potential for delivering a high energy output in proportion to their weight. But such batteries have some pretty serious drawbacks: They waste much of the injected energy as heat and degrade relatively quickly. They also require expensive extra components to pump oxygen gas in and out, in an open-cell configuration that is very different from conventional sealed batteries But a new variation of the battery chemistry, which could be used in a conventional, fully sealed battery, promises similar theoretical performance as lithium-air batteries while overcoming all of these drawbacks. The new battery concept, called a nanolithia cathode battery, is described in the journal Nature Energy in a paper by Ju Li, the Battelle Energy Alliance Professor of Nuclear Science and Engineering at MIT; postdoc Zhi Zhu; and five others at MIT, Argonne National Laboratory, and Peking University in China.   One of the shortcomings of lithium-air batteries, Li explains, is the mismatch between the voltages involved in charging and discharging the batteries.  The batteries’ output voltage is more than 1.2 volts lower than the voltage used to charge them, which represents a significant power loss incurred in each charging cycle. “You waste 30 percent of the electrical energy as heat in charging. … It can actually burn if you charge it too fast,” he says.  Staying solid Conventional lithium-air batteries draw in oxygen from the outside air to drive a chemical reaction with the battery’s lithium during the discharging cycle, and this oxygen is then released again to the atmosphere during the reverse reaction in the charging cycle. In the new variant, the same kind of electrochemical reactions take place between lithium and oxygen during charging and discharging, but they take place without ever letting the oxygen revert to a gaseous form.  Instead, the oxygen stays inside the solid and transforms directly between its three redox states, while bound in the form of three different solid chemical compounds, Li2O, Li2O2, and LiO2, which are mixed together in the form of a glass.  This reduces the voltage loss by a factor of five, from 1.2 volts to 0.24 volts, so only 8 percent of the electrical energy is turned to heat. “This means faster charging for cars, as heat removal from the battery pack is less of a safety concern, as well as energy efficiency benefits,” Li says. This approach helps overcome another issue with lithium-air batteries: As the chemical reaction involved in charging and discharging converts oxygen between gaseous and solid forms, the material goes through huge volume changes that can disrupt electrical conduction paths in the structure, severely limiting its lifetime. The secret to the new formulation is creating minuscule particles, at the nanometer scale (billionths of a meter), which contain both the lithium and the oxygen in the form of a glass, confined tightly within a matrix of cobalt oxide. The researchers refer to these particles as nanolithia. In this form, the transitions between LiO2, Li2O2, and Li2O can take place entirely inside the solid material, he says. The nanolithia particles would normally be very unstable, so the researchers embedded them within the cobalt oxide matrix, a sponge-like material with pores just a few nanometers across. The matrix stabilizes the particles and also acts as a catalyst for their transformations. Conventional lithium-air batteries, Li explains, are “really lithium-dry oxygen batteries, because they really can’t handle moisture or carbon dioxide,” so these have to be carefully scrubbed from the incoming air that feeds the batteries. “You need large auxiliary systems to remove the carbon dioxide and water, and it’s very hard to do this.” But the new battery, which never needs to draw in any outside air, circumvents this issue. No overcharging The new battery is also inherently protected from overcharging, the team says, because the chemical reaction, in this case, is naturally self-limiting — when overcharged, the reaction shifts to a different form that prevents further activity.  “With a typical battery, if you overcharge it, it can cause irreversible structural damage or even explode,” Li says. But with the nanolithia battery, “we have overcharged the battery for 15 days, to a hundred times its capacity, but there was no damage at all.” In cycling tests, a lab version of the new battery was put through 120 charging-discharging cycles, and showed less than a 2 percent loss of capacity, indicating that such batteries could have a long useful lifetime.  And because such batteries could be installed and operated just like conventional solid lithium-ion batteries, without any of the auxiliary components needed for a lithium-air battery, they could be easily adapted to existing installations or conventional battery pack designs for cars, electronics, or even grid-scale power storage. Because these “solid oxygen” cathodes are much lighter than conventional lithium-ion battery cathodes, the new design could store as much as double the amount of energy for a given cathode weight, the team says. And with further refinement of the design, Li says, the new batteries could ultimately double that capacity again. All of this is accomplished without adding any expensive components or materials, according to Li. The carbonate they use as the liquid electrolyte in this battery “is the cheapest kind” of electrolyte, he says.  And the cobalt oxide component weighs less than 50 percent of the nanolithia component. Overall, the new battery system is “very scalable, cheap, and much safer” than lithium-air batteries, Li says. The team expects to move from this lab-scale proof of concept to a practical prototype within about a year. “This is a foundational breakthrough, which may shift the paradigm of oxygen-based batteries,” says Xiulei Ji, an assistant professor of chemistry at Oregon State University, who was not involved in this work.  “In this system, commercial carbonate-based electrolyte works very well with solvated superoxide shuttles, which is quite impressive and may have to do with the lack of any gaseous O2 in this sealed system. All active masses of the cathode throughout cycling are solid, which presents not only large energy density but compatibility with the current battery manufacturing infrastructure.” The research team included MIT research scientists Akihiro Kushima and Zongyou Yin; Lu Qi of Peking University; and Khalil Amine and Jun Lu of Argonne National Laboratory in Illinois. The work was supported by the National Science Foundation and the U.S. Department of Energy. Ref.KY605-CR2025VPKY605-NH12VP

(USC professor Sri Narayan's research focuses on the fundamental and applied aspects of electrochemical energy conversion and storage to reduce the carbon footprint of energy use and by providing energy alternatives to fossil fuel, Wednesday, June 10, 2014 in Los Angeles.) Scientists at USC have developed a water-based organic battery that is long lasting, built from cheap, eco-friendly components. The new battery -- which uses no metals or toxic materials -- is intended for use in power plants, where it can make the energy grid more resilient and efficient by creating a large-scale means to store energy for use as needed. "The batteries last for about 5,000 recharge cycles, giving them an estimated 15-year lifespan," said Sri Narayan, professor of chemistry at the USC Dornsife College of Letters, Arts and Sciences and corresponding author of a paper describing the new batteries that was published online by the Journal of the Electrochemical Society on June 20. "Lithium ion batteries degrade after around 1,000 cycles, and cost 10 times more to manufacture." Narayan collaborated with Surya Prakash, Prakash, professor of chemistry and director of the USC Loker Hydrocarbon Research Institute, as well as USC's Bo Yang, Lena Hoober-Burkhardt, and Fang Wang. "Such organic flow batteries will be game-changers for grid electrical energy storage in terms of simplicity, cost, reliability and sustainability," said Prakash. The batteries could pave the way for renewable energy sources to make up a greater share of the nation's energy generation. Solar panels can only generate power when the sun's shining, and wind turbines can only generate power when the wind blows. That inherent unreliability makes it difficult for power companies to rely on them to meet customer demand. With batteries to store surplus energy and then dole it out as needed, that sporadic unreliability could cease to be such an issue. "'Mega-scale' energy storage is a critical problem in the future of the renewable energy, requiring inexpensive and eco-friendly solutions," Narayan said. The new battery is based on a redox flow design -- similar in design to a fuel cell, with two tanks of electroactive materials dissolved in water. The solutions are pumped into a cell containing a membrane between the two fluids with electrodes on either side, releasing energy. The design has the advantage of decoupling power from energy. The tanks of electroactive materials can be made as large as needed -- increasing total amount of energy the system can store -- or the central cell can be tweaked to release that energy faster or slower, altering the amount of power (energy released over time) that the system can generate. The team's breakthrough centered around the electroactive materials. While previous battery designs have used metals or toxic chemicals, Narayan and Prakash wanted to find an organic compound that could be dissolved in water. Such a system would create a minimal impact on the environment, and would likely be cheap, they figured. Through a combination of molecule design and trial-and-error, they found that certain naturally occurring quinones -- oxidized organic compounds -- fit the bill. Quinones are found in plants, fungi, bacteria, and some animals, and are involved in photosynthesis and cellular respiration. "These are the types of molecules that nature uses for energy transfer," Narayan said. Currently, the quinones needed for the batteries are manufactured from naturally occurring hydrocarbons. In the future, the potential exists to derive them from carbon dioxide, Narayan said. The team has filed several patents in regards to design of the battery, and next plans to build a larger scale version. This research was funded by the ARPA-E Open-FOA program (DE-AR0000337), the University of Southern California, and the Loker Hydrocarbon Research Institute. Ref.ML-621S/DNVL-1220/HFNLC-R061R3P

(Integrated microscale flow batteries could power and cool future three-dimensional chip stacks.). Tightly packed electronic components generate a lot of heat. Tiny redox flow batteries will beneath supplying energy also dissipating the heat they produce. Researchers at ETH Zurich and IBM Research Zurich have built a tiny redox flow battery. This means that future computer chip stacks – in which individual chips are stacked like pancakes to save space and energy – could be supplied with electrical power and cooled at the same time by such integrated flow batteries. In a flow battery, an electrochemical reaction is used to produce electricity out of two liquid electrolytes, which are pumped to the battery cell from outside via a closed electrolyte loop. The chips are effectively operated with a liquid fuel and produce their own electricity. As the scientists use two liquids that are known to be suitable both as flow-battery electrolytes and as a medium to also effect cooling, excess heat can also be dissipated from the chip stack via the same circuit. The battery is only around 1.5 millimetres thick. The idea would be to assemble chip stacks layer by layer: a computer chip, then a thin battery micro-cell that supplies the chip with electricity and cools it, followed by the next computer chip and so on. Record-high outputPrevious flow batteries (see box) are usually large scale and used mainly in stationary energy storage applications, for instance in combination with wind farms and solar power plants, where they temporarily store the energy produced there so it can be used at a later time. These are the first scientists to build such a small flow battery so as to combine energy supply and cooling. The output of the new micro-battery also reaches a record-high in terms of its size: 1.4 watts per square centimetre of battery surface. Even if you subtract the power required to pump the liquid electrolytes to the battery, the resulting net power density is still 1 watt per square centimetre. In an experiment, the electrolyte liquids are actually able to cool a chip. They are even able to dissipate heat amounts many times over what the battery generates as electrical energy (which is converted into heat while the chip is in operation). Channel system optimised with 3D printingThe most serious challenge in constructing the new micro-flow batteries was to build them in such a way that they are supplied with electrolytes as efficiently as possible while at the same time keeping the pumping power as low as possible. It was important to find the ideal compromise. The electrochemical reactions in the battery occur in two thin and porous electrode layers that are separated by a membrane. The scientists used 3D-printing technology to build a polymer channel system to press the electrolyte liquid into the porous electrode layer as efficiently as possible. The most suitable of the various designs tested proved to be one made of wedge-shaped convergent channels. Interesting for large systems, tooThe scientists have now provided an initial proof-of-concept for the construction of a small flow battery. Although the power density of the new micro-flow battery is very high, the electricity produced is still not entirely sufficient to operate a computer chip. In order for the flow battery to be used in a chip stack, it must be further optimised by industry partners. The new approach is also interesting for other applications: in lasers, for example, which have to be supplied with energy and cooled; or for solar cells, where the electricity produced could be stored directly in the battery cell and used later when needed. The system could also keep the operating temperature of the solar cell at the ideal level. In addition, large flow batteries could also be improved with the optimised approach of forcing the electrolyte liquids through the porous electrodes. Ref.ML-2020/H1CNLC-RD1217P

Engineers at the University of Maryland have invented an entirely new kind of battery. It is bio-compatible because it produces the same kind of ion-based electrical energy used by humans and other living things.In our bodies, flowing ions (sodium, potassium and other electrolytes) are the electrical signals that power the brain and control the rhythm of the heart, the movement of muscles, and much more. In traditional batteries, the electrical energy, or current, flows in form of moving electrons. This current of electrons out of the battery is generated within the battery by moving positive ions from one end (electrode) of a battery to the other. The new UMD battery does the opposite. It moves electrons around in the device to deliver energy that is a flow of ions. This is the first time that an ionic current-generating battery has been invented. "My intention is for ionic systems to interface with human systems," said Liangbing Hu, the head of the group that developed that battery. Hu is a professor of materials science at the University of Maryland, College Park. He is also a member of the University of Maryland Energy Research Center and a principal investigator of the Nanostructures for Electrical Energy Storage Energy Frontier Research Center, sponsored by the Department of Energy, which funded the study. "So I came up with the reverse design of a battery," Hu said. "In a typical battery, electrons flow through wires to interface electronics, and ions flow through the battery separator. In our reverse design, a traditional battery is electronically shorted (that means electrons are flowing through the metal wires). Then ions have to flow through the outside ionic cables. In this case, the ions in the ionic cable -- here, grass fibers -- can interface with living systems." The work of Hu and his colleagues was published in the July 24 issue of Nature Communications. "Potential applications might include the development of the next generation of devices to micro-manipulate neuronal activities and interactions that can prevent and/or treat such medical problems as Alzheimer's disease and depression," said group member Jianhua Zhang, PhD, a staff scientist at the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health in Bethesda, Md. "The battery could be used to develop medical devices for the disabled, or for more efficient drug and gene delivery tools in both research and clinical settings, as a way to more precisely treat cancers and other medical diseases, said Zhang, who performed biological experiments to test that the new battery successfully transmitted current to living cells.. "Looking far ahead on the scientific horizon, one hopes also that this invention may help to establish the possibility of direct machine and human communication," he said. Bio-compatible, bio-material batteries Because living cells work on ionic current and existing batteries provide an electronic current, scientists have previously tried to figure out how to create biocompatibility between these two by patching an electronic current into an ionic current. The problem with this approach is that electronic current needs to reach a certain voltage to jump the gap between electronic systems and ionic systems. However, in living systems ionic currents flow at a very low voltage. Thus, with an electronic-to-ionic patch the induced current would be too high to run, say, a brain or a muscle. This problem could be eliminated by using ionic current batteries, which could be run at any voltage. The new UMD battery also has another unusual feature -- it uses grass to store its energy. To make the battery, the team soaked blades of Kentucky bluegrass in lithium salt solution. The channels that once moved nutrients up and down the grass blade were ideal conduits to hold the solution. The demonstration battery the research team created looks like two glass tubes with a blade of grass inside, each connected by a thin metal wire at the top. The wire is where the electrons flow through to move from one end of the battery to the other as the stored energy slowly discharges. At the other end of each glass tube is a metal tip through which the ionic current flows. The researchers proved that the ionic current is flowing by touching the ends of the battery to either end of a lithium-soaked cotton string, with a dot of blue-dyed copper ions in the middle. Caught up in the ionic current, the copper moved along the string toward the negatively charged pole, just as the researchers predicted. "The microchannels in the grass can hold the salt solution, making them a stable ionic conductor," said Chengwei Wang, first author of the paper and a graduate student in the Materials Science and Engineering department at the University of Maryland in College Park. However, the team plans to diversify the types of ionic current electron batteries they can produce. "We are developing multiple ionic conductors with cellulose, hydrogels and polymers," said Wang. This is not the first time UMD scientists have tested natural materials in new uses. Hu and his team previously have been studying cellulose and plant materials for electronic batteries, creating a battery and a supercapacitor out of wood and a battery from a leaf. They also have created transparent wood as a potentially more energy-efficient replacement for glass windows. Creative Work Ping Liu, an associate professor in nanoengineering at the University of California, San Diego, who was not involved with the study, said: "The work is very creative and its main value is in delivering ionic flow to bio systems without posing other dangers to them. Eventually, the impact of the work really resides in whether smaller and more biocompatible junction materials can be found that then interface with cells and organisms more directly and efficiently." Source:University of Maryland Ref.ML-621S/ZTNMS412FE-FL26E  

When you hear the word battery, what do you think? Those annoying pink Duracell rabbits, the ones you have stolen from the back of the remote control or the fact that your phone’s battery may as well cease to exist because nowadays it barely lasts all of five minutes? It is a common fear in most of us, that whilst we are out having a good time your phone’s battery is quickly fading in your pocket. However, we never seem worried about the battery’s eventual lifespan, which for the record is normally between three and five years. There are in fact ways to keep your battery in pristine condition for a long and powerful life; even though batteries do not enjoy eternal life. Many smartphone manufacturers insist that devices rate batteries at 300-500 cycles, which isn’t necessarily good news for us. Apple claims that its laptop batteries reach 80% of their original capacity after just 1,000 charges. After this point batteries aren’t able to hold as much electricity and will power your device for increasingly shorter periods of time. Whilst you taken on all this negative battery news fear not; let’s take a look at some tips to extend your battery’s lifespan, whether that is an iPhone, Android phone, Windows phone, tablet, or laptop. Let’s start with something that is on everyone’s minds – the big question; when re-charging a battery should you let it run to zero before charging full to 100%? One reason why people are unsure is something they’ve heard of called the battery ‘memory effect’. What is battery memory effect?Battery memory effect is about batteries remembering remaining charge if you don’t let them go all the way to zero too often. So a battery frequently charged from 20-80% might ‘forget’ about the 40% that’s left uncharged (0-20% and 80-100%). Sounds like a bit of an old wives tale? Well it sort of is true, but only for older nickel-based (NiMH and NiCd) batteries, not the lithium-ion batteries in your phones now. Fortunately for us, Lithium-ion (Li-ion) batteries don’t suffer the memory effect so you basically what is best for them is the total opposite; charge them often but not all the way throughout the day, and don’t let them drop to zero. Don’t charge your phone battery from zero to 100%The golden rule with Li-ion batteries is to keep them 50% or more most of the time, so when it drops below 50% if you can just top it up a little bit. ‘Little and often’ as they say a few times a day seems to be the optimum to aim for. But ideally don’t charge it all the way to 100%. It won’t be fatal to your battery if you do fully recharge, I mean most of us are forced to do this every now and again in an emergency, but constantly doing a full recharge will shorten the battery’s lifespan. So a good range to aim for when charging a Li-ion battery is from about 40-80% in one go. Try not to let the battery drop below 20%. When should I do a full battery charge?Experts recommend that you do a full zero to 100% battery recharge, or as they call it a ‘charge cycle’ maybe once a month only. This is so the battery can recalibrate - a bit like restarting your computer, or, for humans, going on holiday and relaxing. Another top tip; the same rule applies to laptops. Should I charge my phone overnight?Most modern smartphones are clever enough to stop charging when full, so there isn't a great risk in leaving your phone charging overnight. However some experts have recommended you remove the phone from a case if charging for a long time, as a case could lead to over-heating. This is what Lithium-ion batteries do not like. Should I use fast battery charging?Many Android phones have a feature that allows for fast charging, often referred to as Qualcomm Quick Charge or, in Samsung's case, Adaptive Fast Charging. These phones have special code usually located in a chip known as the Power Management IC (PMIC) that communicates with the charger you are using and requests that it send power at a higher voltage. However, unfortunately for the Apple lovers out there, the iPhone 6 doesn’t feature fast charging, but its Qualcomm PMIC is smart enough to recognise when you use a higher-amp charger (like the one you get with the iPad), which is a good thing because fast charging will heat up that Li-ion battery and cause it increased wear and tear. For this exact reason, phones shouldn’t be left in a hot car, on the beach or next to the oven. Overheating the battery will suffer long-term effects on its lifespan and on the other hand so will a super-cold one, so don’t leave your device in the freezer or out in the snow. If you can, switch off fast charging on your Android phone. Can I use any charger?It is best to use your charger, so where possible use the charger that came with your phone, as it is sure to have the correct rating. Or make sure that a third-party charger is approved by your phone's manufacturer. Cheap alternatives from Amazon or eBay may harm your phone, and there have been several reported cases of cheap chargers actually catching on fire. Storing battery tipsDon’t leave a Li-ion battery li-ing around too long at 0%. Try to leave it at around 40-50%. These batteries drain at about 5-10% a month when not in use. So if you let your battery discharge completely and leave it uncharged for a long period of time it may eventually become incapable of holding a charge at all – RIP it’s officially dead. It’s unlikely you’ll leave your smartphone lying in a drawer for very long, but think about laptops, battery packs or spare batteries that are unused for long periods of time. So try to keep them all at least half charged. Ref.ML-621S/ZTNML-614S/FN

Researchers at Tokyo Institute of Technology have devised a low-cost approach to developing all-solid-state batteries, improving prospects for scaling up the technology for widespread use in electric vehicles, communications and other industrial applications. Ever since batteries were invented over 200 years ago, there has been a drive to improve quality and performance at reduced costs.Compared to common lithium-ion batteries that contain lithium ion conducting liquids, all-solid-state batteries of the future promise a suite of advantages: improved safety and reliability, higher energy storage and longer life cycles. The discovery of ‘superionic’ conductors — solid crystals that enable fast movement of ions — is spurring the development of such dream batteries, but promising designs have so far relied on the use of rare metals such as germanium, making them too expensive for large-scale applications. Ryoji Kanno and colleagues at Tokyo Institute of Technology (Tokyo Tech) have now discovered a new material with a low-cost, scalable approach that involves substituting germanium for two more readily available elements: tin and silicon. The new material achieved an ionic conductivity that exceeds that of liquid electrolytes. Reporting their findings in Chemistry of Materials, the team states: "This germanium-free lithium conductor could be a promising candidate as an electrolyte in all-solid-state batteries." Due to its high chemical stability and ease of fabrication, Kanno says that the new material widens the possibilities of fine-tuning solid electrolytes to meet diverse industry and consumer needs. In 2011, Kanno and his team, working in collaboration with Toyota Motor Corporation and Japan's High Energy Accelerator Research Organisation (KEK), published a landmark paper in Nature Materials that introduced a solid electrolyte with the structure Li10GeP2S12 (LGPS). This material became an important forerunner in the race to develop viable all-solid-state batteries. It exhibited an ionic conductivity of 1.2x10-2S cm-1 at room temperature, a level comparable with — and even exceeding some — liquid electrolytes used in existing batteries. The team went on to design other solid electrolytes based on the same LGPS crystal structure, with promising results. In their latest study, the researchers kept the same framework structure of LGPS, and finely adjusted the ratio and positioning of the tin, silicon and other constituent atoms. The resulting material LSSPS (composition: Li10.35[Sn0.27Si1.08]P1.65S12 (Li3.45[Sn0.09Si0.36]P0.55S4)) achieved an ionic conductivity of 1.1x10-2S cm-1 at room temperature, almost reaching that of the original LGPS structure. Although further work will be required to optimise performance for different usage purposes, the new material raises hopes for low-cost production without sacrificing performance. Kanno envisions that in addition to meeting current battery needs across all sectors, all-solid-state batteries will expand the possibilities of responding to new user needs arising from the IoT and the shift towards smart systems, as well as powering robots, drones and space and aircraft technologies among others in future.  Ref.KY605-NH12VPKY605-NH15VP