POSTECH Professor Byoungwoo Kang’s research team has uncovered a new Li-ion battery electrode material that can achieve high-energy density and high power capability per volume without reducing particle size.

With Tesla in the lead, the electric vehicle market is growing around the world. Unlike conventional cars that use internal combustion engines, electric cars are commonly solely powered by lithium ion batteries, so the battery performance defines the car’s overall performance. However, slow charging times and weak power are still barriers to be overcome. In light of this, a POSTECH research team has recently developed a faster charging and longer lasting battery material for electric cars.

The research teams of Professor Byoungwoo Kang and Dr. Minkyung Kim of the Department of Materials Science and Engineering at POSTECH and Professor Won-Sub Yoon in the Department of Energy Science at Sungkyunkwan University have together proved for the first time that when charging and discharging Li-ion battery electrode materials, high power can be produced by significantly reducing the charging and discharging time without reducing the particle size.

The research findings were published in the recent issue of Energy & Environmental Science, a leading international journal in the energy materials field.

So far, for fast charging and discharging of Li-ion batteries, methods that reduce the particle size of electrode materials were used. However, reducing the particle size has a disadvantage of decreasing the volumetric energy density of the batteries.

About this, the research team confirmed that if an intermediate phase in the phase transition is formed during the charging and discharging, high power can be generated without losing high energy density or reducing the particle size through rapid charging and discharging, enabling the development of long-lasting Li-ion batteries.

In the case of phase separating materials that undergo the process of creating and growing new phases while charging and discharging, two phases with different volumes exist within a single particle, resulting in many structural defects in the interface of the two phases. These defects inhibit the rapid growth of a new phase within the particle, hindering quick charging and discharging.

TEM measurements of particles in electrochemically lithiated samples with DOD50. Structural analyses of the CTR-Li0.5VPO4F (a) Low magnification image with its enlarged image of the dislocation part, (b) Low magnification image and (c) its high resolution image of stacking faults and dislocations. Image Credit: POSTECH. Click image for the largest view.

Using the synthesis method developed by the research team, one can induce an intermediate phase that acts as a structural buffer that can dramatically reduce the change in volume between the two phases in a particle.

Additionally, it has been confirmed that this buffering intermediate phase can help create and grow a new phase within the particle, improving the speed of insertion and removal of lithium in the particle. This in turn proved that the intermediate phase formation can dramatically increase the charging and discharging speed of the cell by creating a homogenous electrochemical reaction in the electrode where numerous particles are composed. As a result, the Li-ion battery electrodes synthesized by the research team charge up to 90% in six minutes and discharge 54% in 18 seconds, a promising sign for developing high-power Li-ion batteries.

Professor Byoungwoo Kang, the corresponding author of the paper said, “The conventional approach has always been a trade-off between its low energy density and the rapid charge and discharge speed due to the reduction in the particle size.” He elaborated, “This research has laid the foundation for developing Li-ion batteries that can achieve quick charging and discharging speed, high energy density, and prolonged performance.”

The research was conducted with the support from the Mid-career Researcher Program and the Radiation Technology Development Program of the National Research Foundation of Korea.

If or when these results are confirmed and the processes used for production are worked out to find a produced battery cost we may be witnessing a sea change in lithium ion’s chemistry and competitiveness with the oncoming other battery chemistries.

Batteries have come a very long way from the carbon cell and lead acid technologies. One has to wonder just how far this field can go and where we are in the journey.

University of Rochester engineers and physicists have created a material that is superconducting at room temperature. The carbonaceous sulfur hydride exhibited superconductivity at about 58 degrees Fahrenheit and a pressure of about 39 million psi. This is the first time that superconducting material has been observed at room temperatures.

Featured as the cover story in the journal Nature, the work was conducted by the lab of Ranga Dias, an assistant professor of physics and mechanical engineering.

Dias said developing materials that are superconducting – without electrical resistance and expulsion of magnetic field at room temperature – is the “holy grail” of condensed matter physics. Sought for more than a century, such materials “can definitely change the world as we know it,” he said.

In setting the new record, Dias and his research team combined hydrogen with carbon and sulfur to photochemically synthesize simple organic-derived carbonaceous sulfur hydride in a diamond anvil cell, a research device used to examine miniscule amounts of materials under extraordinarily high pressure.

Dias, who is also affiliated with the University’s Materials Science and High Energy Density Physics programs explained, “Because of the limits of low temperature, materials with such extraordinary properties have not quite transformed the world in the way that many might have imagined. However, our discovery will break down these barriers and open the door to many potential applications.”

Applications include:

  • Power grids that transmit electricity without the loss of up to 200 million megawatt hours (MWh) of the energy that now occurs due to resistance in the wires.
  • A new way to propel levitated trains and other forms of transportation.
  • Medical imaging and scanning techniques such as MRI and magnetocardiography
  • Faster, more efficient electronics for digital logic and memory device technology.

Ashkan Salamat of the University of Nevada Las Vegas, a coauthor of the discovery said, “We live in a semiconductor society, and with this kind of technology, you can take society into a superconducting society where you’ll never need things like batteries again.”

The amount of superconducting material created by the diamond anvil cells is measured in picoliters – about the size of a single inkjet particle.

The next challenge, Dias says, is finding ways to create the room temperature superconducting materials at lower pressures, so they will be economical to produce in greater volume. In comparison to the millions of pounds of pressure created in diamond anvil cells, the atmospheric pressure of Earth at sea level is about 15 PSI.

First discovered in 1911, superconductivity gives materials two key properties. Electrical resistance vanishes. And any semblance of a magnetic field is expelled, due to a phenomenon called the Meissner effect. The magnetic field lines have to pass around the superconducting material, making it possible to levitate such materials, something that could be used for frictionless high-speed trains, known as maglev trains.

Powerful superconducting electromagnets are already critical components of maglav trains, magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) machines, particle accelerators and other advanced technologies, including early quantum supercomputers.

But the superconducting materials used in the devices usually work only at extremely low temperatures – lower than any natural temperatures on Earth. This restriction makes them costly to maintain – and too costly to extend to other potential applications. “The cost to keep these materials at cryogenic temperatures is so high you can’t really get the full benefit of them,” Dias said.

Previously, the highest temperature for a superconducting material was achieved last year in the lab of Mikhail Eremets at the Max Planck Institute for Chemistry in Mainz, Germany, and the Russell Hemley group at the University of Illinois at Chicago. That team reported superconductivity at -10 to 8 degrees Fahrenheit using lanthanum superhydride.

Researchers have also explored copper oxides and iron-based chemicals as potential candidates for high temperature superconductors in recent years. However, hydrogen – the most abundant element in the universe – also offers a promising building block.

“To have a high temperature superconductor, you want stronger bonds and light elements. Those are the two very basic criteria,” Dias said. “Hydrogen is the lightest material, and the hydrogen bond is one of the strongest. Solid metallic hydrogen is theorized to have high Debye temperature and strong electron-phonon coupling that is necessary for room temperature superconductivity.”

However, extraordinarily high pressures are needed just to get pure hydrogen into a metallic state, which was first achieved in a lab in 2017 by Harvard University professor Isaac Silvera and Dias, then a postdoc in Silvera’s lab.

So, Dias’s lab at Rochester has pursued a “paradigm shift” in its approach, using as an alternative, hydrogen-rich materials that mimic the elusive superconducting phase of pure hydrogen, and can be metalized at much lower pressures.

First the lab combined yttrium and hydrogen. The resulting yttrium superhydride exhibited superconductivity at what was then a record high temperature of about 12 degrees Fahrenheit and a pressure of about 26 million pounds per square inch.

Next the lab explored covalent hydrogen-rich organic-derived materials.

This work resulted in the carbonaceous sulfur hydride. “This presence of carbon is of tantamount importance here,” the researchers report. Further “compositional tuning” of this combination of elements may be the key to achieving superconductivity at even higher temperatures, they add.

This is definitely a milestone in the superconductor hunt. Operating up to the 58°F level is a light coat weather temperature. It’s huge progress. What to do about those pressures is still to be worked out. It going to take some time. But with so many working on superconductors in so many places there are sure to be more ideas that gain more progress. For now though, this team is the leader and deserves the cover story notation at Nature.

A joint research team from POSTECH and Korea University has demonstrated a daytime radiative cooling material which exhibits lower temperatures than its surroundings even during the day.

Now that autumn is here, there is a large temperature gap between day and night. This is due to the temperature inversion caused by radiative cooling on the Earth’s surface. Heat from the sun during the day causes its temperature to rise and when the sun sets during the night, its temperature cools down.

Professor Junsuk Rho and Ph.D. candidate Dasol Lee of departments of mechanical engineering and chemical engineering and Professor Jin Kon Kim and Ph.D. candidate Myeongcheol Go in the Department of Chemical Engineering at POSTECH have conducted a joint study with Professor Heon Lee of Materials Science Engineering at Korea University to successfully realize an energy-free radiative cooling technology using silica-coated porous anodic aluminum oxide.

Fabricated Cooler view left, top view center, cross section right. Image Credit: POSTECH. Click Image for the largest view.

The study was published in the latest online edition of Nano Energy, an international journal in the energy sector.

Temperature measured over three days. Radiative Cooler shown with green line and ambient with black line. Image Credit: POSTECH. Click image for the largest view.

With growing interest in energy consumption, such as environmental pollution and limitations in using fossil fuels, attempts to lower the temperature without consuming energy continue. Radiative cooling is an example of structures installed on windows or walls to reduce the building temperature by reflecting sunlight or by absorbing and radiating far-infrared light. Radiative cooling is a technology that allows objects to receive less energy from the sun and lower temperatures by emitting radiative heat.

Unlike conventional cooling systems, radiative cooling is difficult to apply to large areas, although it has the advantage of significantly reducing energy consumption like electricity. Research to overcome this issue is being actively carried out around the world but it is still challenging to commercialize the technology.

To answer the challenge, the joint research team found a very simple solution. Just by coating the porous anodic aluminum with a thin film of silica, it has been confirmed that there is a cooling effect that exhibits a lower temperature than the surroundings even under direct sunlight.

Experiments have confirmed that an optimized structure can have a reflectivity of 86% in the solar spectral region and a high emissivity of 96% in the atmospheric window (8-13 µm). In addition, the radiative cooling material – produced in centimeters – showed a cooling efficiency of up to 6.1°C during the day when the sunlight was strong.

“This newly developed radiative cooling material can be easily produced,” explained POSTECH Professor Junsuk Rho. He added optimistically, “It will help solve environmental problems if applied to heating and cooling systems since it can be readily applied to large areas.”

Surely, this has to be a home run, disruptive or breakthrough technology. 6.1°C (almost 11°F) is a big deal. It could very well make life in the tropics much more comfortable and far less costly to cool further. It would even be quite the boon in the temperate region as well. Home and office radiative cooling is also just the start of the useful applications. Congratulations to this team and best wishes for a rapid adoption of the technology. There is also the challenge to others – Beat This!!

UCLA scientists have developed nanoscale copper wires with specially shaped surfaces to catalyze a chemical reaction that reduces CO2 gas emissions  recycling  the CO2 while generating ethylene – a valuable chemical simultaneously.

The Caltech and the UCLA Samueli School of Engineering team demonstrated the new catalyst to efficiently convert carbon dioxide into ethylene, which is an important chemical used to produce plastics, solvents, cosmetics and other important products worldwide.

Computational studies of the reaction show the shaped catalyst favors the production of ethylene over hydrogen or methane.

The teams study paper detailing the advance has been published in Nature Catalysis.

Illustration of the ElectroCatalysis system which synthesized the smooth nanowire and then activated it by applying a voltage to get the rough stepped surface that is highly selective for CO2 reduction to ethylene. Image Credit: Huang and Goddard, UCLA & Caltech. Click image for the largest view.

Yu Huang, the study’s co-corresponding author, and professor of materials science and engineering at UCLA said, “We are at the brink of fossil fuel exhaustion, coupled with global climate change challenges. Developing materials that can efficiently turn greenhouse gases into value-added fuels and chemical feedstocks is a critical step to mitigate global warming while turning away from extracting increasingly limited fossil fuels. This integrated experiment and theoretical analysis presents a sustainable path towards carbon dioxide recycling and utilization.”

Currently, ethylene has a global annual production of 158 million tons. Much of that is turned into polyethylene, which is used in plastic packaging. Ethylene is processed from hydrocarbons, such as natural gas.

William A. Goddard III, the study’s co-corresponding author and Caltech’s Charles and Mary Ferkel Professor of Chemistry, Materials Science, and Applied Physics said, “The idea of using copper to catalyze this reaction has been around for a long time, but the key is to accelerate the rate so it is fast enough for industrial production. This study shows a solid path towards that mark, with the potential to transform ethylene production into a greener industry using CO2 that would otherwise end up in the atmosphere.”

Using copper to kick start the carbon dioxide (CO2) reduction into ethylene reaction (C2H4) has suffered two strikes against it. First, the initial chemical reaction also produced hydrogen and methane – both undesirable in industrial production. Second, previous attempts that resulted in ethylene production did not last long, with conversion efficiency tailing off as the system continued to run.

To overcome these two hurdles, the researchers focused on the design of the copper nanowires with highly active “steps” – similar to a set of stairs arranged at atomic scale. One intriguing finding of this collaborative study is that this step pattern across the nanowires’ surfaces remained stable under the reaction conditions, contrary to general belief that these high energy features would smooth out. This is the key to both the system’s durability and selectivity in producing ethylene, instead of other end products.

The team demonstrated a carbon dioxide-to-ethylene conversion rate of greater than 70%, much more efficient than previous designs, which yielded at least 10% less under the same conditions. The new system ran for 200 hours, with little change in conversion efficiency, a major advance for copper-based catalysts. In addition, the comprehensive understanding of the structure-function relation illustrated a new perspective to design highly active and durable CO2 reduction catalyst in action.

Huang and Goddard have been frequent collaborators for many years, with Goddard’s research group focusing on the theoretical reasons that underpin chemical reactions, while Huang’s group has created new materials and conducted experiments. The lead author on the paper is Chungseok Choi, a graduate student in materials science and engineering at UCLA Samueli and a member of Huang’s laboratory.

This is quite a feat. CO2 is famed for being a very stable and unreactive molecule. Being able to recycle CO2 would be a boon for chemical production and sooth the fears of the CO2 is bad folks. Just everyone keep in mind, CO2 is the basic plant food, too little and the plant kingdom starves and shortly thereafter so do we.

Meanwhile, one has to wonder what process engineers think the cost might be for a pure CO2 stream to feed the new, but un cost analyzed, catalyst. . . Ethylene is not terribly expensive right now.

Stanford University researchers have designed a new model that offers a way to predict the condition of a battery’s internal systems in real-time with far more accuracy than existing tools. In electric cars, the technology could improve driving range estimates and prolong battery life.

The reality is batteries fade as they age, slowly losing power and storage capacity. As with people, aging plays out differently from one battery to another, and it’s next to impossible to measure or model all of the interacting mechanisms that contribute to decline. As a result, most of the systems used to manage charge levels wisely and to estimate driving range in electric cars are nearly blind to changes in the battery’s internal workings.

Instead, they operate more like a doctor prescribing treatment without knowing the state of a patient’s heart and lungs, and the particular ways that environment, lifestyle, stress and luck have ravaged or spared them. If you’ve kept a laptop or phone for enough years, you may have seen where this leads firsthand: Estimates of remaining battery life tend to diverge further from reality over time.

Now, a model developed by scientists at Stanford University offers a way to predict the true condition of a rechargeable battery in real-time. The new algorithm combines sensor data with computer modeling of the physical processes that degrade lithium-ion battery cells to predict the battery’s remaining storage capacity and charge level.

Simona Onori, assistant professor of energy resources engineering in Stanford’s School of Earth, Energy & Environmental Sciences said, “We have exploited electrochemical parameters that have never been used before for estimation purposes.”

Their research paper has been published in the journal IEEE Transactions on Control Systems Technology.

The new approach could help pave the way for smaller battery packs and greater driving range in electric vehicles. Automakers today build in spare capacity in anticipation of some unknown amount of fading, which adds extra cost and materials, including some that are scarce or toxic. Better estimates of a battery’s actual capacity will enable a smaller buffer.

Onori explained, “With our model, it’s still important to be careful about how we are using the battery system. But if you have more certainty around how much energy your battery can hold throughout its entire lifecycle, then you can use more of that capacity. Our system reveals where the edges are, so batteries can be operated with more precision.”

The accuracy of the predictions in this model – within 2 percent of actual battery life as gathered from experiments, according to the paper – could also make it easier and cheaper to put old electric car batteries to work storing energy for the power grid. “As it is now, batteries retired from electric cars will vary widely in their quality and performance,” Onori said. “There has been no reliable and efficient method to standardize, test or certify them in a way that makes them competitive with new batteries custom-built for stationary storage.”

Every battery has two electrodes – the cathode and the anode – sandwiching an electrolyte, usually a liquid. In a rechargeable lithium-ion battery, lithium ions shuttle back and forth between the electrodes during charging and discharging. An electric car may run on hundreds or thousands of these small battery cells, assembled into a big battery pack that typically accounts for about 30 percent of the total vehicle cost.

Traditional battery management systems typically rely on models that assume the amount of lithium in each electrode never changes, said lead study author Anirudh Allam, a PhD student in energy resources engineering. “In reality, however, lithium is lost to side reactions as the battery degrades,” he said, “so these assumptions result in inaccurate models.”

Onori and Allam designed their system with continuously updated estimates of lithium concentrations and a dedicated algorithm for each electrode, which adjusts based on sensor measurements as the system operates. They validated their algorithm in realistic scenarios using standard industry hardware.

The model relies on data from sensors found in the battery management systems running in electric cars on the road today. “Our algorithm can be integrated into current technologies to make them operate in a smarter fashion,” Onori said. In theory, many cars already on the road could have the algorithm installed on their electronic control units, she said, but the expense of that kind of upgrade makes it more likely that automakers would consider the algorithm for vehicles not yet in production.

The team focused their experiments on a type of lithium-ion battery commonly used in electric vehicles (lithium nickel manganese cobalt oxide) to estimate key internal variables such as lithium concentration and cell capacity. But the framework is general enough that it should be applicable to other kinds of lithium-ion batteries and to account for other mechanisms of battery degradation.

“We showed that our algorithm is not just a nice theoretical work that can run on a computer,” Onori said. “Rather, it is a practical, implementable algorithm which, if adopted and used in cars tomorrow, can result in the ability to have longer-lasting batteries, more reliable vehicles and smaller battery packs.”

This software looked like a home run . . . right up to “the expense of that kind of upgrade” slaps the reader head on. It sounds like these folks expect to license the software ala’ Microsoft. Good luck. Methinks I’ll get along without, too.


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