Lithium News

A team of battery researchers led by the University of California San Diego and University of Chicago has developed a new methodology to produce the potentially game-changing thin-film solid-state electrolyte called lithium phosphorus oxynitride (LiPON). The team went on to implement their free-standing version of LiPON film in functional battery tests and found that it promotes a uniformly dense lithium metal electrochemical deposition under zero external pressure, with the aid of internal compressive stress and a gold seeding layer. This work, performed by a team of battery researchers led by the University of California San Diego and University of Chicago, was published in the journal Nature Nanotechnology on August 03, 2023. The research team is led by battery researcher and professor Ying Shirley Meng, who is affiliated with both the University of Chicago and UC San Diego. The first author is Diyi Cheng, a recently graduated Ph.D. in the Materials Science and Engineering Program at the UC San Diego Jacobs School of Engineering who is continuing his research efforts at Lawrence Berkeley National Laboratory. The team also includes researchers from Lawrence Livermore National Laboratory and UC Berkeley. LiPON is a thin-film solid-state electrolyte that conducts lithium ions and shows strong promise for pairing with a broad range of electrode materials for the lithium battery industry of the future. However, existing methods for producing LiPON have prevented researchers from fully understanding the material. Now, the team found a way to produce this promising solid-state electrolyte in a free-standing form that allows LiPON to be studied more comprehensively. The new approach to making LiPON has also opened the door to using this solid-state electrolyte to enable lithium metal solid-state batteries that could work under minimal external pressure.

The LiPON Challenge

LiPON was originally developed by a group of scientists at Oak Ridge National Laboratory in 1992. Despite continuous research efforts over the last three decades, there remains a substantial lack of thorough understanding of LiPON’s intrinsic properties and its associated interfaces, holding back the promise and advancement of LiPON materials. Several factors leading to this dilemma include:

• LiPON is an amorphous material that gives little structural information by regular diffraction-based techniques.
• LiPON is sensitive to ambient air and electron beams, which further confines the available tools for study.
• Traditional LiPON synthesis is conducted on solid substrates. This approach is inadequate for generating conclusive signals for spectroscopic measurements.

New approach to LiPON production leads to new insights

Given the known challenges to studying LiPON, the team developed a new methodology for producing LiPON film in a free-standing form. The result is a flexible and transparent free-standing LiPON (FS-LiPON) film that is compatible with a broad range of spectroscopic techniques that have greater chances of unraveling the unique properties of LiPON over the diffraction-based techniques. This advance yielded fresh insights, described in the new Nature Nanotechnology paper on LiPON’s interfacial chemistry, thermal properties and mechanical properties. Insights include:

• Solid-state nuclear magnetic resonance measurement uncoverd a quantitative view of interface formation between lithium metal and LiPON
• Differential scanning calorimetry measurements showed a well-defined glass-transition temperature of LiPON around 207 degrees Celsius
• Nanoindentation measurement gave a Young’s modulus of LiPON around 33 GPa

Uniformly dense lithium metal deposition under zero external pressure

In addition to gleaning new fundamental insights on LiPON, the research team also implemented the new free-standing version of the solid-state electrolyte in functional battery tests. The team reports that the thin-film FS-LiPON promotes a uniformly dense lithium metal electrochemical deposition under zero external pressure, with the aid of internal compressive stress and a gold seeding layer. This finding gives valuable hints regarding interface engineering in bulk solid-state batteries. LiPON-based thin film batteries have shown great potential for wearables and other compact electronic devices with a gigantic market. The FS-LiPON film produced in this work described by Diyi Cheng et al. in Nature Nanotechnology enabled in-depth discussions on interfacial chemistry, ion diffusion and interface engineering, which shed light on both the fundamentals and applications of LiPON materials, and could benefit the lithium solid-state battery development in many ways. “A free-standing lithium phosphorus oxynitride thin film electrolyte promotes uniformly dense lithium metal deposition with no external pressure,” is published in Nature Nanotechnology.

Rather than being solely detrimental, cracks in the positive electrode of lithium-ion batteries reduce battery charge time, research done at the University of Michigan shows.

This runs counter to the view of many electric vehicle manufacturers, who try to minimize cracking because it decreases battery longevity.

“Many companies are interested in making ‘million-mile’ batteries using particles that do not crack. Unfortunately, if the cracks are removed, the battery particles won’t be able to charge quickly without the extra surface area from those cracks,” said Yiyang Li, assistant professor of materials science and engineering and corresponding author of the study published in Energy & Environmental Science. “On a road trip, we don’t want to wait five hours for a car to charge. We want to charge within 15 or 30 minutes.”

The team believes the findings apply to more than half of all electric vehicle batteries, in which the positive electrode—or cathode—is composed of trillions of microscopic particles made of either lithium nickel manganese cobalt oxide or lithium nickel cobalt aluminum oxide.

Theoretically, the speed at which the cathode charges comes down to the particles’ surface-to-volume ratio. Smaller particles should charge faster than larger particles because they have a higher surface area relative to volume, so the lithium ions have shorter distances to diffuse through them.

However, conventional methods couldn’t directly measure the charging properties of individual cathode particles, only the average for all the particles that make up the battery’s cathode. That limitation means the widely accepted relationship between charging speed and cathode particle size was merely an assumption.

“We find that the cathode particles are cracked and have more active surfaces to take in lithium ions—not just on their outer surface, but inside the particle cracks,” said Jinhong Min, a doctoral student in materials science and engineering working in Li’s lab. “Battery scientists know that the cracking occurs but have not measured how such cracking affects the charging speed.”

Measuring the charging speed of individual cathode particles was key to discovering the upside to cracking cathodes, which Li and Min accomplished by inserting the particles into a device that is typically used by neuroscientists to study how individual brain cells transmit electrical signals.

“Back when I was in graduate school, a colleague studying neuroscience showed me these arrays that they used to study individual neurons. I wondered if we can also use them to study battery particles, which are similar in size to neurons,” Li said.

Each array is a custom-designed, 2-by-2 centimeter chip with up to 100 microelectrodes. After scattering some cathode particles in the center of the chip, Min moved single particles onto their own electrodes on the array using a needle around 70 times thinner than a human hair. Once the particles were in place, Min could simultaneously charge and discharge up to four individual particles at a time on the array and measured 21 particles in this particular study.

The experiment revealed that the cathode particles’ charging speeds did not depend on their size. Li and Min think that the most likely explanation for this unexpected behavior is that larger particles actually behave like a collection of smaller particles when they crack. Another possibility is that the lithium ions move very quickly in the grain boundaries—the tiny spaces between the nanoscale crystals comprising the cathode particle.

Li thinks this is unlikely unless the battery’s electrolyte—the liquid medium in which the lithium ions move—penetrates these boundaries, forming cracks.

The benefits of cracked materials are important to consider when designing long-lived batteries with single-crystal particles that don’t crack. To charge quickly, these particles may need to be smaller than today’s cracking cathode particles. The alternative is to make single-crystal cathodes with different materials that can move lithium faster, but those materials could be limited by the supply of necessary metals or have lower energy densities, Li said.

Subaru Corporation and Panasonic Energy Co., Ltd. revealed that they have initiated discussions to establish a medium- to long-term partnership. The purpose of the collaboration is to meet the surging demand for battery electric vehicles and automotive batteries in the rapidly expanding EV segment.

Subaru and Panasonic Energy would hold discussions to explore the possibility of the battery maker supplying the automaker with next-generation automotive cylindrical lithium-ion batteries. As stated in a press release, Subaru would then install the Panasonic batteries to battery electric cars that would be produced in the latter half of the decade.

These vehicles would be produced in sites such as a a dedicated EV plant that is expected to be built in Gunma, Japan.

Subaru is taking strides towards electrification. The company has set a roadmap toward 2050 with the aim of contributing to the realization of a carbon-neutral society. Panasonic Energy, as the automaker’s partner, would help Subaru achieve this goal by supplying the automaker with high-performance cylindrical lithium-ion batteries.

While Panasonic is not the world’s largest battery maker, its cylindrical batteries for electric vehicles are among the best in the industry. Panasonic’s 18650 cells, for example, have been used by Tesla in vehicles such as the original Roadster, but they are still powering the EV maker’s flagship cars today, the Model S Plaid and Model X Plaid.

Panasonic is also arguably one of the industry’s most experienced EV battery suppliers. It is then no surprise that other automakers such as Mazda have also entered discussions with the Japanese firm for potential medium- to long-term battery supply deals. Subaru is not exactly leading the pack with pure electric cars, so a deal with Panasonic would likely help the automaker.

Li-Cycle today launched one of Europe’s largest lithium-ion battery recycling centers, and it can process full EV battery packs.

Li-Cycle in Germany

Toronto-headquartered Li-Cycle’s first European battery recycling center – what the company calls a “Spoke” – is in Magdeburg, Germany, northwest of Leipzig.

The Magdeburg Spoke’s first main processing line at the 20,000-square-meter (215,000-square-foot) facility is online and is capable of processing full EV battery packs. Its second main line is expected to launch later this year.

Each main line has the capacity to process up to 10,000 tonnes of Li-ion battery material annually.

The company says it has an “additional 10,000 tonnes of ancillary capacity planned.” So if that goes forward, then the Magdeburg Spoke (pictured above) would have a total capacity of 30,000 tonnes per year, which would make it one of the largest facilities of its kind in Europe.

Spokes and Hubs

Li-Cycle (NYSE: LICY) already has four Spokes: in Kingston, Ontario, in Canada; and in Rochester, New York, Gilbert, Arizona, and Tuscaloosa, Alabama, in the US.

Including Magdeburg, Li-Cycle says it expects to have a total input processing capacity of up to 81,000 tonnes of lithium-ion battery material annually.

Li-Cycle’s Spokes produce an intermediate product called “black mass,” which includes such valuable battery materials as lithium, nickel, and cobalt. It plans to process the black mass the Spokes produce at its future “Hub” facilities. Its Hubs will process the materials into battery-grade end products for reuse.

The company’s first planned Hub facility, which was awarded a $375 million loan from the US Department of Energy in February, is under construction in Rochester and is expected to come online later this year.

Li-Cycle has said it will also develop a second commercial Hub in Europe – a 50/50 venture with Swiss mining giant Glencore. The two companies plan to repurpose part of an existing Glencore metallurgical complex in Portovesme, Italy, in Sardinia, to create what will be known as the Portovesme Hub.

A feasibility study for the Portovesme project is currently underway, and if it goes forward, it will be one of the largest sources of recycled battery-grade lithium, nickel, and cobalt in Europe.

FIFTY YEARS AFTER the birth of the rechargeable lithium-ion battery, it’s easy to see its value. It’s used in billions of laptops, cellphones, power tools, and cars. Global sales top US $45 billion a year, on their way to more than $100 billion in the coming decade.

And yet this transformative invention took nearly two decades to make it out of the lab, with numerous companies in the United States, Europe, and Asia considering the technology and yet failing to recognize its potential.

The first iteration, developed by M. Stanley Whittingham at Exxon in 1972, didn’t get far. It was manufactured in small volumes by Exxon, appeared at an electric vehicle show in Chicago in 1977, and served briefly as a coin cell battery. But then Exxon dropped it.

Various scientists around the world took up the research effort, but for some 15 years, success was elusive. It wasn’t until the development landed at the right company at the right time that it finally started down a path to battery world domination.

Did Exxon invent the rechargeable lithium battery?

In the early 1970s, Exxon scientists predicted that global oil production would peak in the year 2000 and then fall into a steady decline. Company researchers were encouraged to look for oil substitutes, pursuing any manner of energy that didn’t involve petroleum.

Whittingham, a young British chemist, joined the quest at Exxon Research and Engineering in New Jersey in the fall of 1972. By Christmas, he had developed a battery with a titanium-disulfide cathode and a liquid electrolyte that used lithium ions.

Whittingham’s battery was unlike anything that had preceded it. It worked by inserting ions into the atomic lattice of a host electrode material—a process called intercalation. The battery’s performance was also unprecedented: It was both rechargeable and very high in energy output. Up to that time, the best rechargeable battery had been nickel cadmium, which put out a maximum of 1.3 volts. In contrast, Whittingham’s new chemistry produced an astonishing 2.4 volts.

In the winter of 1973, corporate managers summoned Whittingham to the company’s New York City offices to appear before a subcommittee of the Exxon board. “I went in there and explained it—5 minutes, 10 at the most,” Whittingham told me in January 2020. “And within a week, they said, yes, they wanted to invest in this.”

Whittingham’s battery, the first lithium intercalation battery, was developed at Exxon in 1972 using titanium disulfide for the cathode and metallic lithium for the anode.JOHAN JARNESTAD/THE ROYAL SWEDISH ACADEMY OF SCIENCES

It looked like the beginning of something big. Whittingham published a paper in Science; Exxon began manufacturing coin cell lithium batteries, and a Swiss watch manufacturer, Ebauches, used the cells in a solar-charging wristwatch.

But by the late 1970s, Exxon’s interest in oil alternatives had waned. Moreover, company executives thought Whittingham’s concept was unlikely to ever be broadly successful. They washed their hands of lithium titanium disulfide, licensing the technology to three battery companies—one in Asia, one in Europe, and one in the United States.

“I understood the rationale for doing it,” Whittingham said. “The market just wasn’t going to be big enough. Our invention was just too early.”

Oxford takes the handoff

It was the first of many false starts for the rechargeable lithium battery. John B. Goodenough at the University of Oxford was the next scientist to pick up the baton. Goodenough was familiar with Whittingham’s work, in part because Whittingham had earned his Ph.D. at Oxford. But it was a 1978 paper by Whittingham, “Chemistry of Intercalation Compounds: Metal Guests in Chalcogenide Hosts,” that convinced Goodenough that the leading edge of battery research was lithium. [Goodenough passed away on 25 June at the age of 100.]

Goodenough and research fellow Koichi Mizushima began researching lithium intercalation batteries. By 1980, they had improved on Whittingham’s design, replacing titanium disulfide with lithium cobalt oxide. The new chemistry boosted the battery’s voltage by another two-thirds, to 4 volts.

Goodenough wrote to battery companies in the United States, United Kingdom, and the European mainland in hopes of finding a corporate partner, he recalled in his 2008 memoir, Witness to Grace. But he found no takers.

He also asked the University of Oxford to pay for a patent, but Oxford declined. Like many universities of the day, it did not concern itself with intellectual property, believing such matters to be confined to the commercial world.

Goodenough’s 1980 battery replaced Whittingham’s titanium disulfide in the cathode with lithium cobalt oxide.JOHAN JARNESTAD/THE ROYAL SWEDISH ACADEMY OF SCIENCES

Still, Goodenough had confidence in his battery chemistry. He visited the Atomic Energy Research Establishment (AERE), a government lab in Harwell, about 20 kilometers from Oxford. The lab agreed to bankroll the patent, but only if the 59-year-old scientist signed away his financial rights. Goodenough complied. The lab patented it in 1981; Goodenough never saw a penny of the original battery’s earnings.

For the AERE lab, this should have been the ultimate windfall. It had done none of the research, yet now owned a patent that would turn out to be astronomically valuable. But managers at the lab didn’t see that coming. They filed it away and forgot about it.

Asahi Chemical steps up to the plate

The rechargeable lithium battery’s next champion was Akira Yoshino, a 34-year-old chemist at Asahi Chemical in Japan. Yoshino had independently begun to investigate using a plastic anode—made from electroconductive polyacetylene—in a battery and was looking for a cathode to pair with it. While cleaning his desk on the last day of 1982, he found a 1980 technical paper coauthored by Goodenough, Yoshino recalled in his autobiography, Lithium-Ion Batteries Open the Door to the Future, Hidden Stories by the Inventor. The paper—which Yoshino had sent for but hadn’t gotten around to reading—described a lithium cobalt oxide cathode. Could it work with his plastic anode?

Yoshino, along with a small team of colleagues, paired Goodenough’s cathode with the plastic anode. They also tried pairing the cathode with a variety of other anode materials, mostly made from different types of carbons. Eventually, he and his colleagues settled on a carbon-based anode made from petroleum coke.

Yoshino’s battery, developed at Asahi Chemical in the late 1980s, combined Goodenough’s cathode with a petroleum coke anode. JOHAN JARNESTAD/THE ROYAL SWEDISH ACADEMY OF SCIENCES

This choice of petroleum coke turned out to be a major step forward. Whittingham and Goodenough had used anodes made from metallic lithium, which was volatile and even dangerous. By switching to carbon, Yoshino and his colleagues had created a battery that was far safer.

Still, there were problems. For one, Asahi Chemical was a chemical company, not a battery maker. No one at Asahi Chemical knew how to build production batteries at commercial scale, nor did the company own the coating or winding equipment needed to manufacture batteries. The researchers had simply built a crude lab prototype.

Enter Isao Kuribayashi, an Asahi Chemical research executive who had been part of the team that created the battery. In his book, A Nameless Battery with Untold Stories, Kuribayashi recounted how he and a colleague sought out consultants in the United States who could help with the battery’s manufacturing. One consultant recommended Battery Engineering, a tiny firm based in a converted truck garage in the Hyde Park area of Boston. The company was run by a small band of Ph.D. scientists who were experts in the construction of unusual batteries. They had built batteries for a host of uses, including fighter jets, missile silos, and downhole drilling rigs.