May
8
Tokyo University of Science scientists have discovered a stable, highly conductive lithium-ion conductor in the form of a pyrochlore-type oxyfluoride. It’s an innovation addressing the need for non-sulfide solid electrolytes.
All-solid-state lithium-ion batteries offer enhanced safety and energy density compared to liquid electrolyte counterparts, but face challenges like lower conductivity and insufficient electrode contact. The non-sulfide solid electrolytes, offer higher conductivity and stability and pave the way for advanced all-solid-state lithium-ion batteries with improved performance and safety.
The study paper has been published in Chemistry of Materials. A research team led by Professor Kenjiro Fujimoto, Professor Akihisa Aimi from Tokyo University of Science, and Dr. Shuhei Yoshida from DENSO CORPORATION, discovered a stable and highly conductive Li-ion conductor in the form of a pyrochlore-type oxyfluoride.
Three Dimensional Ionic Conducting Path of Pyrochlore Type Oxyflouride. More details in the study paper text. Image Credit: Tokyo University of Science.
All-solid-state lithium-ion (Li-ion) batteries with solid electrolytes are non-flammable and have higher energy density and transference numbers than those with liquid electrolytes. They are expected to take a share of the market for conventional liquid electrolyte Li-ion batteries, such as electric vehicles.
However, despite these advantages, solid electrolytes have lower Li-ion conductivity and pose challenges in achieving adequate electrode-solid electrolyte contact. While sulfide-based solid electrolytes are conductive, they react with moisture to form toxic hydrogen disulfide. Therefore, there’s a need for non-sulfide solid electrolytes that are both conductive and stable in air to make safe, high-performance, and fast-charging solid-state Li-ion batteries.
According to Prof. Fujimoto, “Making all-solid-state lithium-ion secondary batteries has been a long-held dream of many battery researchers. We have discovered an oxide solid electrolyte that is a key component of all-solid-state lithium-ion batteries, which have both high energy density and safety. In addition to being stable in air, the material exhibits higher ionic conductivity than previously reported oxide solid electrolytes.”
The pyrochlore-type oxyfluoride studied in this work can be denoted as Li2-xLa(1+x)/3M2O6F (M = Nb, Ta). It underwent structural and compositional analysis using various techniques, including X-ray diffraction, Rietveld analysis, inductively coupled plasma optical emission spectrometry, and selected-area electron diffraction. Specifically, Li1.25La0.58Nb2O6F was developed, demonstrating a bulk ionic conductivity of 7.0 mS cm⁻¹ and a total ionic conductivity of 3.9 mS cm⁻¹ at room temperature.
It was found to be higher than the lithium-ion conductivity of known oxide solid electrolytes. The activation energy of ionic conduction of this material is extremely low, and the ionic conductivity of this material at low temperature is one of the highest among known solid electrolytes, including sulfide-based materials.Exactly, even at -10° C, the new material has the same conductivity as conventional oxide-based solid electrolytes at room temperature. Furthermore, since conductivity above 100° C has also been verified, the operating range of this solid electrolyte is -10 °C to 100° C. Conventional lithium-ion batteries cannot be used at temperatures below freezing. Therefore, the operating conditions of lithium-ion batteries for commonly used mobile phones are 0° C to 45° C.
The Li-ion conduction mechanism in this material was investigated. The conduction path of pyrochlore-type structure cover the F ions located in the tunnels created by MO6 octahedra. The conduction mechanism is the sequential movement of Li-ions while changing bonds with F ions. Li ions move to the nearest Li position always passing through metastable positions. Immobile La3+ bonded to F ion inhibits the Li-ion conduction by blocking the conduction path and vanishing the surrounding metastable positions.
Unlike existing lithium-ion secondary batteries, oxide-based all solid-state batteries have no risk of electrolyte leakage due to damage and no risk of toxic gas generation as with sulfide-based batteries. Therefore, this new innovation is anticipated to lead future research. “The newly discovered material is safe and exhibits higher ionic conductivity than previously reported oxide-based solid electrolytes. The application of this material is promising for the development of revolutionary batteries that can operate in a wide range of temperatures, from low to high,” envisions Prof. Fujimoto. “We believe that the performance required for the application of solid electrolytes for electric vehicles is satisfied.”
Notably, the new material is highly stable and will not ignite if damaged. It is suitable for airplanes and other places where safety is critical. It is also suitable for high-capacity applications, such as electric vehicles, because it can be used under high temperatures and supports rapid recharging. Moreover, it is also a promising material for miniaturization of batteries, home appliances, and medical devices.
In summary, researchers have not only discovered a Li-ion conductor with high conductivity and air stability but also introduced a new type of superionic conductor with a pyrochlore-type oxyfluoride. Exploring the local structure around lithium, their dynamic changes during conduction, and their potential as solid electrolytes for all-solid-state batteries are important areas for future research!
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This news has generated quite a bit of high level battery excitement. But the absence of some form of economic cost has left quite a few at the opening lines. How this tech compares to the better current manufacturing art isn’t discussed in term of production costs.
But you can bet there are folks looking into it. This tech gets one a non ignitable lithium ion battery that works from about 13º F to 212º F. The non combustible angle has more import than most folks will assume.
Still, a battery has quite a bit of energy in a confined space. Just what the risks might be are yet to be disclosed. But Wow!
This looks good.
May
7
An international team including researchers from the University of Würzburg has succeeded in creating a special state of superconductivity. The discovery could advance the development of quantum computers.
Superconductors are materials that can conduct electricity without electrical resistance – making them the ideal base material for electronic components in MRI machines, magnetic levitation trains and even particle accelerators. However, conventional superconductors are easily disturbed by magnetism. An international group of researchers has now succeeded in building a hybrid device consisting of a stable proximitized-superconductor enhanced by magnetism and whose function can be specifically controlled.
Sample holder for measurements at millikelvin (-273° C). Image Credit: Mandal/JMU, seitlich erweitert mit Firefly. University of Würzburg. Click the press release link for the largest view.
They combined the superconductor with a special semiconductor material known as a topological insulator. “Topological insulators are materials that conduct electricity on their surface but not inside. This is due to their unique topological structure, i.e. the special arrangement of the electrons,” explained Professor Charles Gould, a physicist at the Institute for Topological Insulators at the University of Würzburg (JMU). “The exciting thing is that we can equip topological insulators with magnetic atoms so that they can be controlled by a magnet.”
The superconductors and topological insulators were coupled to form a so-called Josephson junction, a connection between two superconductors separated by a thin layer of non-superconducting material. “This allowed us to combine the properties of superconductivity and semiconductors”, said Gould. “So we combine the advantages of a superconductor with the controllability of the topological insulator. Using an external magnetic field, we can now precisely control the superconducting properties. This is a true breakthrough in quantum physics!”
Superconductivity Meets Magnetism
The special combination creates an exotic state in which superconductivity and magnetism are combined – normally these are opposite phenomena that rarely coexist. This is known as the proximity-induced Fulde-Ferrell-Larkin-Ovchinnikov (p-FFLO) state. The new “superconductor with a control function” could be important for practical applications, such as the development of quantum computers. Unlike conventional computers, quantum computers are based not on bits but on quantum bits (qubits), which can assume not just two but several states simultaneously.
“The problem is that quantum bits are currently very unstable because they are extremely sensitive to external influences, such as electric or magnetic fields,” explained physicist Gould. “Our discovery could help stabilize quantum bits so that they can be used in quantum computers in the future.”
International Quantum Research Team
The experimental research was carried out by a team from the Chair of Experimental Physics III of Professor Laurens W. Molenkamp in Würzburg. It was carried out in close collaboration with theoretical experts from the group of Professor F. Sebastian Bergeret of the Centre for Materials Physics (CFM) in San Sebastian, Spain, and Professor Teun M. Klapwijk of Delft University of Technology in the Netherlands.
The international research group was funded by the Cluster of Excellence ct.qmat (Complexity and Topology in Quantum Materials), the German Research Foundation (DFG), the Free State of Bavaria, the Spanish Agencia Estatal de Investigación (AEI), the European research programme Horizon 2020 and the EU ERC Advanced Grant Programme.
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This does answer in part one of the questions that interested observers have had for years about the natural magnetic field around an energized superconductor. It’s not much of a surprise that an intrusive magnetic field would wreak some havoc on a super conductor. Yet, it’s also quite a surprise that the prospective technology is already coming into focus.
One day, it looks like the temperature issue will be the only major one left.
May
2
Some materials are transparent to light of a certain frequency. When such light is shone on them, electrical currents can still be generated, contrary to previous assumptions.
Scientists from Leipzig University and Nanyang Technological University in Singapore have managed to prove this. The scientists have published their findings in the journal Physical Review Letters.
Inti Sodemann Villadiego, Professor at the Institute of Theoretical Physics at Leipzig University commented, “This opens new paradigms for constructing opto-electronic and photovoltaic devices, such as light amplifiers, sensors and solar cells.”
His colleague Li-kun Shi added, “It is possible to drive electric currents by light even when the material has a vanishingly small absorption of such light. This is an important new insight.”
Inti Sodemann Villadiego and his colleagues investigated what are known as “Floquet Fermi liquid” states.
A Fermi liquid is a special state of many quantum mechanical particles with properties that can be very different from those of ordinary classical liquids such as water at ambient temperature.
Fermi liquids can arise in a wide variety of situations, from common materials such as the electrical fluid of electrons in metals like gold or silver, to more exotic situations such as the fluid of Helium-3 atoms at low temperatures.
They can display “spectacular properties,” such as becoming superconductors of electricity at low temperatures.
The “Floquet Fermi liquid” is a variant of this state realized when the particles of the fluid are periodically shaken, such as what happens to electrons in metals when they are illuminated by ideally periodic light.
“In our publication, we explain several properties of these fluid states,” says Professor Sodemann Villadiego. “To study them, we had to develop detailed theoretical models of complex states of electrons shaken by light, which is far from easy.”
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Those new paradigms for constructing opto-electronic and photovoltaic devices have a wide array of possibilities listed. Just where the imaginations of designers and engineers can go with this is without a border today.
The payoff might be sooner than what one might think. Lots of smiles about this and an important journal picked the paper up.
Materials research looks to have a new field opening up!
May
1
Image Credit: Princeton Plasma Physics Laboratory. Click the press release link for the largest view and more images.
That idea is inspiring a new approach to managing plasma, the super-hot state of matter, for use as a fusion power source. Scientists are using the imperfections in magnetic fields that confine a reaction to improve and enhance the plasma in an approach outlined in a new paper in the journal Nature Communications.
Joseph Snipes, the PPPL’s deputy head of the Tokamak Experimental Science Department and a co-author of the paper said, “This approach allows you to maintain a high-performance plasma, controlling instabilities in the core and the edge of the plasma simultaneously. That simultaneous control is particularly important and difficult to do. That’s what makes this work special.”
PPPL Physicist Seong-Moo Yang led the research team, which spans various institutions in the U.S. and South Korea. Yang says this is the first time any research team has validated a systematic approach to tailoring magnetic field imperfections to make the plasma suitable for use as a power source. These magnetic field imperfections are known as error fields.
“Our novel method identifies optimal error field corrections, enhancing plasma stability,” Yang said. “This method was proven to enhance plasma stability under different plasma conditions, for example, when the plasma was under conditions of high and low magnetic confinement.”
Errors that are hard to correct
Error fields are typically caused by minuscule defects in the magnetic coils of the device that holds the plasma, which is called a tokamak
Until now, error fields were only seen as a nuisance because even a very small error field could cause a plasma disruption that halts fusion reactions and can damage the walls of a fusion vessel. Consequently, fusion researchers have spent considerable time and effort meticulously finding ways to correct error fields.
“It’s quite difficult to eliminate existing error fields, so instead of fixing these coil irregularities, we can apply additional magnetic fields surrounding the fusion vessel in a process known as error field correction,” Yang said.
In the past, this approach would have also hurt the plasma’s core, making the plasma unsuitable for fusion power generation. This time, the researchers were able to eliminate instabilities at the edge of the plasma and maintain the stability of the core. The research is a prime example of how PPPL researchers are bridging the gap between today’s fusion technology and what will be needed to bring fusion power to the electrical grid.
SangKyeun Kim, a staff research scientist at PPPL and paper co-author explained, “This is actually a very effective way of breaking the symmetry of the system, so humans can intentionally degrade the confinement. It’s like making a very tiny hole in a balloon so that it will not explode.” Just as air would leak out of a small hole in a balloon, a tiny quantity of plasma leaks out of the error field, which helps to maintain its overall stability.
Managing the core and the edge of the plasma simultaneously
One of the toughest parts of managing a fusion reaction is getting both the core and the edge of the plasma to behave at the same time. There are ideal zones for the temperature and density of the plasma in both regions, and hitting those targets while eliminating instabilities is tough.
This study demonstrates that adjusting the error fields can simultaneously stabilize both the core and the edge of the plasma. By carefully controlling the magnetic fields produced by the tokamak’s coils, the researchers could suppress edge instabilities, also known as edge localized modes (ELMs), without causing disruptions or a substantial loss of confinement.
PPPL Staff Research Physicist Qiming Hu, another author of the paper noted, “We are trying to protect the device.”
Extending the research beyond KSTAR
The research was conducted using the KSTAR tokamak in South Korea, which stands out for its ability to adjust its magnetic error field configuration with great flexibility. This capability is crucial for experimenting with different error field configurations to find the most effective ones for stabilizing the plasma.
The researchers say their approach has significant implications for the design of future tokamak fusion pilot plants, potentially making them more efficient and reliable. They are currently working on an artificial intelligence (AI) version of their control system to make it more efficient.
“These models are fairly complex; they take a bit of time to calculate. But when you want to do something in a real-time control system, you can only afford a few milliseconds to do a calculation,” said Snipes. “Using AI, you can basically teach the system what to expect and be able to use that artificial intelligence to predict ahead of time what will be necessary to control the plasma and how to implement it in real-time.”
While their new paper highlights work done using KSTAR’s internal magnetic coils, Hu suggests future research with magnetic coils outside of the fusion vessel would be valuable because the fusion community is moving away from the idea of housing such coils inside the vacuum-sealed vessel due to the potential destruction of such components from the extreme heat of the plasma.
Researchers from the Korea Institute of Fusion Energy (KFE), Columbia University and Seoul National University were also integral to the project.
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With a large array of devices trying to hold the plasma in place long enough to enter fusion and stay that way — every bit of know-how that can be gained is worthwhile. Controlling plasma is very difficult activity. Getting good enough at it to start fusion, keep it going, and get net energy out is going to be a challenge noteworthy for all of history.
Apr
30
Research Shows How to Build A Better Cheaper Magnet
April 30, 2024 | Leave a Comment
National Institute for Materials Science, Japan scientists have succeeded in simulating the magnetization reversal of Nd-Fe-B (neodymium iron boron) magnets. The simulation was made possible by using large-scale finite element models construction based on tomographic data obtained by electron microscopy.
a Acquisition of a series of FIB-SEM images for a hot-deformed Nd-Fe-B magnet (cropped area of 0.8 × 0.8 µm2 is shown). b Processing of the images including 2D segmentation and the conversion of grain slices into point clouds. c Generation of close-packed 3D convex grains isolated from each other by the intergranular phase. Triple junctions are made invisible except for a zoomed region showing the mesh around one of them. Image Credit: National Institute for Materials Science, Japan. For the largest view click here for the open access (at time of posting) study paper. Also, the press release offers other images and simplified information.
Such simulations have shed light on microstructural features that hinder the “coercivity”, a metric that quantifies a magnet’s resistance to demagnetization in opposing magnetic fields. The new tomography-based models are expected to guide toward the development of sustainable permanent magnets with ultimate performance.
Green power generation, electric transportation, and other high-tech industries rely heavily on high-performance permanent magnets, among which the Nd-Fe-B magnets are the strongest and most in demand.
The coercivity of industrial Nd-Fe-B magnets is far below its physical limit up to now.To resolve this issue, micromagnetic simulations on realistic models of the magnets can be employed.
A new approach to reconstruct the real microstructure of ultrafine-grained Nd-Fe-B magnets in large-scale models is proposed in this research.
Specifically, the tomographic data from a series of 2D images obtained by scanning electron microscopy (SEM) in combination with consistent focused ion beam (FIB) polishing can be converted into a high-quality 3D finite element model.
This tomography-based approach is universal and can be applied to other polycrystalline materials addressing a wide range of materials science problems. Micromagnetic simulations on the tomography-based models reproduced the coercivity of ultrafine-grained Nd-Fe-B magnets and explained its mechanism.
The microstructural features relevant to the coercivity and nucleation of magnetization reversal were revealed. Thus, the developed model can be considered as a digital twin of Nd-Fe-B magnets — a virtual representation of an object designed to reflect its physics accurately.
The proposed digital twins of the Nd-Fe-B magnets are precise enough in reproducing both the microstructure and magnetic properties that can be implemented for the inverse problem in designing on-demand high-performance permanent magnets.
For instance, when researchers input the magnetic properties required for a specific application (e.g., traction or variable magnetic force motor), a data-driven research pipeline with integrated digital twins will be able to propose the optimal composition, processing conditions, and microstructure of the magnet for that application, significantly reducing development time.
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The point of all this is solving the problem of designing alternative on-demand high-performance permanent magnets. This is no small problem. Right now the magnet production, raw material sourcing and processing are pretty much fully controlled by the Chinese Communist Party.
That makes this kid of work a national security issue for a huge array of nations. The stated intentions of the communists aren’t the kinds of things that build better living standards, increase the security of humanity, or improve the health, wealth, and safety of people across the planet.
So, this is critical research. A “Thank You” to this research team is offered and hopes for more funding to flesh out more of the whole this research can offer.
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