By: Neal Dawson-Elli, Seong Beom Lee, Manan Pathak, Kishalay Mitra, and Venkat R. Subramanian

This article refers to a recently published open access paper in the Journal of The Electrochemical Society, “Data Science Approaches for Electrochemical Engineers: An Introduction through Surrogate Model Development for Lithium-Ion Batteries.”

Data science is often hailed as the fourth paradigm of science. As the computing power available to researchers increases, data science techniques become more and more relevant to a larger group of scientists. A quick literature search for electrochemistry and data science will reveal a startling lack of analysis done on the data science side. This paper is an attempt to help introduce the topics of data science to electrochemists, as well as to analyze the power of these methods when combined with physics-based models.

At the core of the paper is the idea that one cannot be successful treating every problem as a black box and applying liberal use of data science – in other words, despite its growing popularity, it is not a panacea. The image shows the basic workflow for using data science techniques – the creation of a dataset, splitting into training-test pairs, training a model, and then evaluating the model on some task. In this case, the training data comes from many simulations of the pseudo two-dimensional lithium-ion battery model. However, in order to get the best results, one cannot simply pair the inputs and outputs and train a machine learning model on it. The inputs, or features, must be engineered to better highlight changes in your output data, and sometimes the problem needs to be totally restructured in order to be successful.

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In order to increase the driving range of electric vehicles, researchers across the globe are working to develop lithium-ion batteries with higher energy storage. Now, scientists at Chungnam National University and Kumoh National Institute of Technology in Korea are taking a step toward that goal with their development of the first high-voltage cathode binder for higher energy Li-ion batteries.

Today’s Li-ion batteries are limited to charge to 4.2V due to the electrochemical instability of the liquid electrolyte and cathode-electrolyte interface, and loosening of conventional binder, polyvinylidenefluoride (PVdF), particularly at elevated temperatures. The fabrication of Li-rich layered oxide cathode with a novel high-voltage binder, as the research team demonstrated, can overcome these limitations.

Charging the batteries with Li-rich layered oxide cathode (xLi₂MnO₃∙(1−x)LiMO2, M = Mn, Ni, Co) to higher than 4.5V produces approximately doubled capacity than those with LiCoO₂ cathode, so that doubled energy density batteries can be achieved.

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A team of researchers from the Joint Center for Energy Storage Research is taking a potential major step toward developing energy dense, safe solid state magnesium-ion batteries.

This research marks another step in pursing batteries that utilize solid electrolytes, which could offer significant safety benefits over conventional lithium-ion batteries.

The work was developed out of efforts to create a magnesium battery with a liquid electrolyte. While magnesium has promising properties for energy storage, the researchers had trouble finding a viable liquid electrolyte for the technology that wouldn’t corrode.

“Magnesium is such a new technology, it doesn’t have any good liquid electrolytes,” said Gerbrand Ceder, co-author of the research and member of ECS. “We thought, why not leapfrog and make a solid state electrolyte?”

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Capitalizing on tiny defects can improve electrodes for lithium-ion batteries, new research suggests.

In a study on lithium transport in battery cathodes, researchers found that a common cathode material for lithium-ion batteries, olivine lithium iron phosphate, releases or takes in lithium ions through a much larger surface area than previously thought.

“We know this material works very well but there’s still much debate about why,” says Ming Tang, an assistant professor of materials science and nanoengineering at Rice University. “In many aspects, this material isn’t supposed to be so good, but somehow it exceeds people’s expectations.”

Part of the reason, Tang says, comes from point defects—atoms misplaced in the crystal lattice—known as antisite defects. Such defects are impossible to completely eliminate in the fabrication process. As it turns out, he says, they make real-world electrode materials behave very differently from perfect crystals.

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A new kind of lithium sulfur battery could be more efficient, less expensive, and safer than currently available lithium batteries.

“We demonstrated this method in a coin battery,” says Donghai Wang, associate professor of mechanical engineering at Penn State. “But, I think it could eventually become big enough for cell phones, drones, and even bigger for electric vehicles.”

Lithium sulfur batteries should be a promising candidate for the next generation of rechargeable batteries, but they are not without problems. For lithium, the efficiency in which charge transfers is low, and, lithium batteries tend to grow dendrites—thin branching crystals—when charging that do not disappear when discharged.

The researchers examined a self-formed, flexible hybrid solid-electrolyte interphase layer that is deposited by both organosulfides and organopolysulfides with inorganic lithium salts. The researchers report that the organic sulfur compounds act as plasticizers in the interphase layer and improve the mechanical flexibility and toughness of the layer. The interphase layer allows the lithium to deposit without growing dendrites. The Coulombic efficiency is about 99 percent over 400 recharging discharging cycles.

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A new sodium-based battery can store the same amount of energy as a state-of-the-art lithium ion at a substantially lower cost.

As a warming world moves from fossil fuels toward renewable solar and wind energy, industrial forecasts predict an insatiable need for battery farms to store power and provide electricity.

Chemical engineer Zhenan Bao and materials scientists Yi Cui and William Chueh of Stanford University aren’t the first researchers to design a sodium ion battery. But they believe their approach has the price and performance characteristics to create a sodium ion battery that costs less than 80 percent of a lithium ion battery with the same storage capacity.

$150 a ton

“Nothing may ever surpass lithium in performance,” Bao says. “But lithium is so rare and costly that we need to develop high-performance but low-cost batteries based on abundant elements like sodium.”

With materials constituting about one-quarter of a battery’s price, the cost of lithium—about $15,000 a ton to mine and refine—looms large. Researchers say that’s why they are basing the new battery on widely available sodium-based electrode material that costs just $150 a ton.

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Lithium batteries made with asphalt could charge 10 to 20 times faster than the commercial lithium-ion batteries currently available.

The researchers developed anodes comprising porous carbon made from asphalt that show exceptional stability after more than 500 charge-discharge cycles.

A high-current density of 20 milliamps per square centimeter demonstrates the material’s promise for use in rapid charge and discharge devices that require high-power density.

“The capacity of these batteries is enormous, but what is equally remarkable is that we can bring them from zero charge to full charge in five minutes, rather than the typical two hours or more needed with other batteries,” says James Tour, the chair in chemistry and a professor of computer science and of materials science and nanoengineering at Rice University.

The Tour lab previously used a derivative of asphalt—specifically, untreated gilsonite, the same type used for the battery—to capture greenhouse gases from natural gas. This time, the researchers mixed asphalt with conductive graphene nanoribbons and coated the composite with lithium metal through electrochemical deposition.

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The electric vehicle market continues to build momentum every year, with consumers around the world growing more interested. But in order for EVs to pave the way for the future of transportation, more efficient, longer-lasting batteries will need to be developed.

That’s where ECS member Jeff Dahn, leader of Tesla’s researcher partnership through his Dalhousie University research group, comes in. Recently, Dahn and his team unveiled new chemistry that could increase battery lifecycle at high voltages without significant degradation.

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The consumer demand for seamless, integrated technology is on the rise, and with it grows the Internet of Things, which is expected to grow to a multitrillion-dollar market by 2020. But in order to develop a fully integrated electronic network, flexible, lightweight, rechargeable power sources will be required.

A team of researchers from Ulsan National Institute of Science and Technology is looking to address that issue, developing inkjet-printed batteries that can be modified to fit devices of any shape and size. The team reports that the newly developed inks can be printed onto paper to create a new class of printed supercapacitors.

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This from Ulsan National Institute of Science and Technology:

The process involves using a conventional inkjet printer to print a preparatory coating—a ‘wood cellulose-based nanomat’—onto a normal piece of A4 paper. Next, an ink of activated carbon and single-walled nanotubes is printed onto the nanomat, followed by an ink made of silver nanowires in water. These two inks form the electrodes. Finally, an electrolyte ink—formed of an ionic liquid mixed with a polymer that changes its properties when exposed to ultraviolet light—is printed on top of the electrodes. The inks are exposed at various stages to ultraviolet irradiation and finally the whole assembly is sealed onto the piece of paper with an adhesive film.

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A team of scientists from Oak Ridge National Laboratory is using the precision of an electron beam to instantly adhere cathode coatings for lithium-ion batteries. This new development, as reported in the Journal of The Electrochemical Society, could lead to a leap in efficiency that saves energy, reduces production cost, and eliminates the use of toxic solvents.

This from ORNL:

The technique uses an electron beam to cure coating material as it rolls down the production line, creating instantaneous cross-links between molecules that bind the coating to a foil substrate, without the need for solvents, in less than a second.

Read the full article.

“Typical curing processes can require drying machinery the length of a football field and expensive equipment for solvent recovery,” says David Wood, co-author of the study. “This approach presents a promising avenue for fast, energy-efficient manufacturing of high-performance, low-cost lithium-ion batteries.”

Read the full paper, “Electron Beam Curing of Composite Positive Electrode for Li-Ion Battery.”