Solar Energy

Finding key to low-cost, fast production of solid-state batteries for EVs

Published

4 years ago

March 9, 2021

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Finding key to low-cost, fast production of solid-state batteries for EVs

A new fabrication technique could allow solid-state automotive lithium-ion batteries to adopt nonflammable ceramic electrolytes using the same production processes as in batteries made with conventional liquid electrolytes.

The melt-infiltration technology developed by materials science researchers at the Georgia Institute of Technology uses electrolyte materials that can be infiltrated into porous yet densely packed, thermally stable electrodes.

The one-step process produces high-density composites based on pressure-less, capillary-driven infiltration of a molten solid electrolyte into porous bodies, including multilayered electrode-separator stacks.

“”While the melting point of traditional solid state electrolytes can range from 700 degrees Celsius to over 1,000 degrees Celsius, we operate at a much lower temperature range, depending on the electrolyte composition, roughly from 200 to 300 degrees Celsius,” explained Gleb Yushin, a professor in the School of Materials Science and Engineering at Georgia Tech. “At these lower temperatures, fabrication is much faster and easier. Materials at low temperatures don’t react. The standard electrode assemblies, including the polymer binder or glue, can be stable in these conditions.”

The new technique, to be reported March 8 in the journal Nature Materials, could allow large automotive Li-ion batteries to be made safer with 100% solid-state nonflammable ceramic rather than liquid electrolytes using the same manufacturing processes of conventional liquid electrolyte battery production.

The patent-pending manufacturing technology mimics low-cost fabrication of commercial Li-ion cells with liquid electrolytes, but instead uses solid state electrolytes with low melting points that are melted and infiltrated into dense electrodes. As a result, high-quality multi-layered cells of any size or shape could be rapidly manufactured at scale using proven tools and processes developed and optimized over the last 30 years for Li-ion.

“Melt-infiltration technology is the key advance. The cycle life and stability of Li-ion batteries depend strongly on the operating conditions, particularly temperature,” Georgia Tech graduate student Yiran Xiao explained.

“If batteries are overheated for a prolonged period, they commonly begin to degrade prematurely, and overheated batteries may catch on fire. That has prompted nearly all electric vehicles (EV) to include sophisticated and rather expensive cooling systems.” In contrast, solid-state batteries may only require heaters, which are significantly less expensive than cooling systems.

Yushin and Xiao are encouraged by the potential of this manufacturing process to enable battery makers to produce lighter, safer, and more energy-dense batteries.

“”The developed melt-infiltration technology is compatible with a broad range of material chemistries, including so-called conversion-type electrodes. Such materials have been demonstrated to increase automotive cell energy density by over 20% now and by more than 100% in the future,” said co-author and Georgia Tech research scientist Kostiantyn Turcheniuk, noting that higher density cells support longer driving ranges. The cells need high-capacity electrodes for that performance leap.

Georgia Tech’s technique is not yet commercially ready, but Yushin predicts that if a significant portion of the future EV market embraces solid-state batteries, “This would probably be the only way to go,” since it will allow manufacturers to use their existing production facilities and infrastructure.

“That’s why we focused on this project – it was one of the most commercially viable areas of innovation for our lab to pursue,” he said.

Battery cell prices hit $100 per kilowatt hour for the first time in 2020. According to Yushin, they will need to drop below $70 per kilowatt hour before the consumer EV market can fully open. Battery innovation is critical to that occurring.

The Materials Science lab team currently is focused on developing other electrolytes that will have lower melting points and higher conductivities using the same technique proven in the lab.

Yushin envisions this research team’s manufacturing advance opening the floodgates to more innovation in this area.

“So many incredibly smart scientists are focused on solving very challenging scientific problems, while completely ignoring economic and technical practicality. They are studying and optimizing very high-temperature electrolytes that are not only dramatically more expensive to use in cells but are also up to five times heavier compared with liquid electrolytes,” he explained. “My goal is to push the research community to look outside that chemical box.”

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Solar Energy

Scientists Probe Declining Earbud Battery Longevity

Published

16 hours ago

February 5, 2025

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Scientists Probe Declining Earbud Battery Longevity

by Clarence Oxford

Los Angeles CA (SPX) Feb 05, 2025

Have you ever noticed how electronic devices, including wireless earbuds, seem to lose battery capacity faster the longer you use them? An international research team from The University of Texas at Austin set out to examine this familiar issue, known as battery degradation, by focusing on the earbuds that many people rely on daily. Through a series of x-ray, infrared, and other imaging approaches, the researchers investigated the hidden complexities behind these tiny devices and revealed why their battery life declines over time.

“This started with my personal headphones; I only wear the right one, and I found that after two years, the left earbud had a much longer battery life,” said Yijin Liu, an associate professor in the Cockrell School of Engineering’s Walker Department of Mechanical Engineering, who led the new research published in Advanced Materials. “So, we decided to look into it and see what we could find.”

Their analysis showed that crucial earbud features – like the Bluetooth antenna, microphones, and circuits – compete with the battery in a very confined space, producing a microenvironment that is less than ideal. This situation results in a temperature gradient that damages the battery over time, with different sections of the cell experiencing variable temperatures.

Real-world factors also complicate matters. Frequent changes in climate, shifts in air quality, and a host of other environmental variables challenge the battery’s resilience. While cells are generally designed to endure harsh conditions, constant fluctuations can take their toll.

These discoveries highlight the importance of considering how batteries interact with devices such as phones, laptops, and even electric vehicles. Packaging solutions, strategic design decisions, and adaptations for user habits may all play a role in extending battery performance.

“Using devices differently changes how the battery behaves and performs,” said Guannan Qian, the first author of this paper and a postdoctoral researcher in Liu’s lab. “They could be exposed to different temperatures; one person has different charging habits than another; and every electric vehicle owner has their own driving style. This all matters.”

In conducting this study, Liu and his team worked closely with UT’s Fire Research Group, led by mechanical engineer Ofodike Ezekoye. They paired infrared imaging methods with their in-house x-ray technology at UT Austin and Sigray Inc. To expand their scope, they then teamed up with some of the world’s most advanced x-ray facilities.

Their collaborators included researchers from SLAC National Accelerator Laboratory’s Stanford Synchrotron Radiation Lightsource, Brookhaven National Laboratory’s National Synchrotron Light Source II, Argonne National Laboratory’s Advanced Photon Source, and the European Synchrotron Radiation Facility (ESRF) in France. These partnerships allowed them to observe battery behavior under more authentic operating conditions.

“Most of the time, in the lab, we’re looking at either pristine and stable conditions or extremes,” said Xiaojing Huang, a physicist at Brookhaven National Laboratory. “As we discover and develop new types of batteries, we must understand the differences between lab conditions and the unpredictability of the real world and react accordingly. X-ray imaging can offer valuable insights for this.”

Looking ahead, Liu says his team will continue analyzing battery performance in the settings people experience every day. They plan to expand their approach to larger batteries, such as those in smartphones, laptops, and electric vehicles, to learn more about their degradation patterns.

Research Report:In-device Battery Failure Analysis

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Solar Energy

Quantum factors elevate plant energy transport efficiency

Published

16 hours ago

February 5, 2025

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Quantum factors elevate plant energy transport efficiency

by Robert Schreiber

Munich, Germany (SPX) Feb 05, 2025

For countless engineers, converting sunlight into easily stored chemical energy stands as an enduring goal. Yet nature perfected this challenge billions of years ago. A recent study reveals that quantum mechanics, once thought to be limited to physics, is also essential for key biological processes.

Green plants and other photosynthetic organisms draw on quantum mechanical mechanisms to capture the sun’s energy. According to Prof. Jurgen Hauer: “When light is absorbed in a leaf, for example, the electronic excitation energy is distributed over several states of each excited chlorophyll molecule; this is called a superposition of excited states. It is the first stage of an almost loss-free energy transfer within and between the molecules and makes the efficient onward transport of solar energy possible. Quantum mechanics is therefore central to understanding the first steps of energy transfer and charge separation.”

Classical physics alone cannot completely describe how this phenomenon unfolds throughout green plants and in certain photosynthetic bacteria. Although the exact details remain only partly understood, Prof. Hauer and first author Erika Keil consider their new findings an important step toward uncovering how chlorophyll, the pigment behind leaf coloration, functions. Applying these insights to engineered photosynthesis devices could unlock unprecedented solar energy conversion efficiencies for both power production and photochemical applications.

In their investigation, the researchers focused on two portions of the light spectrum absorbed by chlorophyll: the low-energy Q band (yellow to red) and the high-energy B band (blue to green). In the Q region, two electronic states are quantum mechanically coupled, promoting virtually loss-free energy movement. The system subsequently relaxes via “cooling”, i.e. by releasing energy in the form of heat. These observations demonstrate that quantum mechanical processes can play a major role in shaping key biological functions.

Research Report:Reassessing the role and lifetime of Qx in the energy transfer dynamics of chlorophyll a

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Solar Energy

HZB sets new efficiency record for CIGS perovskite tandem solar cells

Published

17 hours ago

February 5, 2025

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HZB sets new efficiency record for CIGS perovskite tandem solar cells

by Robert Schreiber

Berlin, Germany (SPX) Feb 05, 2025

Researchers at Helmholtz Center Berlin for Materials and Energy (HZB) and Humboldt University Berlin have developed a CIGS-perovskite tandem solar cell that has set a new world record for efficiency, achieving 24.6%. The performance of the cell has been officially certified by the Fraunhofer Institute for Solar Energy Systems.

Thin-film solar cells, such as those based on copper, indium, gallium, and selenium (CIGS), require minimal material and energy to manufacture, making them an environmentally friendly alternative to conventional silicon-based solar cells. CIGS thin films can also be applied to flexible substrates, expanding their potential applications.

The new tandem solar cell developed by HZB and Humboldt University combines a CIGS bottom cell with a perovskite top cell. By optimizing the contact layers between these two components, the research team successfully increased efficiency to a record-breaking 24.6%. This milestone was confirmed by the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg, Germany.

This achievement was made possible through a collaborative effort among researchers. The top cell was developed by Thede Mehlhop, a master’s student at TU Berlin, under the supervision of Stefan Gall. The perovskite absorber layer was created in the joint laboratory of HZB and Humboldt University Berlin, while the CIGS sub-cell and contact layers were fabricated by HZB researcher Guillermo Farias Basulto. Additionally, the KOALA high-performance cluster system at HZB was used to deposit the perovskite and contact layers in a vacuum.

“At HZB, we have highly specialized laboratories and experts who are top performers in their fields. With this world record tandem cell, they have once again shown how fruitfully they work together,” said Prof. Rutger Schlatmann, spokesman for the Solar Energy Department at HZB.

HZB has a strong track record in achieving world records in solar cell efficiency, including past accomplishments in silicon-perovskite tandem cells and now in CIGS-perovskite tandem technology.

“We are confident that CIGS-perovskite tandem cells can achieve much higher efficiencies, probably more than 30%,” said Prof. Rutger Schlatmann.