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University of Michigan uses recycled Kevlar fiber to solve lithium-sulfur battery life cycle issues
The University of Michigan Chemical Sciences and Engineering team, led by Professor Nicholas Kotov, has developed a “new biologically inspired battery membrane” with recycled Kevlar fibers that could quintuple electric vehicle ranges and have a lifespan of 1,000 cycles.
The Ann Arbor, Michigan research facility is one of the best in the world, and Kotov, whose research focuses on the development of biomimetic nanocomposites, the self-assembly of nanoparticles, and chiral nanostructures, has worked to change the narrative on lithium-sulfur cells. “There are a number of reports claiming several hundred cycles for lithium-sulfur batteries, but it is achieved at the expense of other parameters—capacity, charging rate, resilience, and safety,” Kotov said in a press release from the University. “The challenge nowadays is to make a battery that increases the cycling rate from the former 10 cycles to hundreds of cycles and satisfies multiple other requirements including cost.”
Lithium-sulfur batteries can enable five times the capacity of standard lithium-ion cells, which are used in electric vehicles. However, as Professor Kotov mentioned in his quote, the lifespan is significantly decreased due to chemical reactions between molecules. The most common reason for reduced life cycles in lithium-sulfur batteries is dendrites, which are appendages that are designed to receive communications from other cells. These can pierce the membrane of cells, reducing the life span and thus the life cycle of a battery cell.
Another problem is polysulfides, or small molecules of lithium and sulfur, can form and flow to the lithium. They bond and cause blockages, reducing the effectiveness of the membrane. “The membrane is needed to allow lithium ions to flow from the lithium to the sulfur and back—and to block the lithium and sulfur particles, known as lithium polysulfides.”
However, Kevlar, the same material used in bulletproof vests, can stop dendrites from penetrating the membrane using dense aramid fibers found in the material. The cells that Kotov and his team developed use recycled Kevlar fibers. The Kevlar “can enable lithium-sulfur batteries to overcome their Achilles heel of cycle life,” caused by the two previously mentioned reactions between molecules.
An example of the Kevlar system is shown in the images below, as the typical Celgard membrane on the left allows lithium polysulfides to flow through. The Kevlar membrane (right) blocked the polysulfides from traveling through.
“Just half an hour on, the Celgard membrane (left) leaks lithium polysulfides. However, the U-M membrane (right) completely blocks the lithium polysulfides 96 hours later. Image credit: Ahmet Emre, Kotov Lab.” Credit: University of Michigan
“Achieving record levels for multiple parameters for multiple materials properties is what is needed now for car batteries,” Kotov stated. Kotov added that the design of the lithium-sulfur batteries is “nearly perfect” due to its capacity and efficiency reaching theoretical limits. It can also behave more resiliently than lithium-ion cells in warm and cold weather climates, which both have effects on range and efficiency. However, fast charging could reduce the number of lifespans, Kotov added.
Lithium-sulfur batteries could be a good alternative as sulfur is more readily available and abundant than cobalt, which is controversial due to its mining practices. However, automakers like Tesla are reducing cobalt in their batteries vying for other metals, like nickel, instead. Sulfur’s low lifespan and instability, as it changes in size by 78 percent during charging, reduced the possibility of automakers using it in the past, The Independent reported.
The research was funded by the National Science Foundation and the Department of Defense.
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News
Tesla FSD successfully completes full coast-to-coast drive with zero interventions
Tesla community members celebrated the milestone on X, and the feat earned praise from some of the electric vehicle maker’s executives.
A Tesla owner has successfully completed a full coast-to-coast drive across the United States on Full Self-Driving (FSD) Supervised. The trip was accomplished with zero interventions.
Tesla community members celebrated the milestone on X, and the feat earned praise from some of the electric vehicle maker’s executives.
FSD Coast-to-Coast
The coast-to-coast feat was accomplished by Tesla owner Davis Moss, who drives a stealth gray Model 3 with AI4 hardware. Based on data from the FSD database and a community tracker, the last 10,638.8 miles Moss drove in his Model 3 were completed using FSD 100% of the time. His vehicle is equipped with FSD v14.2.1.25, which was installed 12 days ago.
As per Moss in a celebratory post on X, his Model 3 was able to complete a full coast-to-coast drive across the United States in 2 days and 20 hours. His trip started at the Tesla Diner in Los Angeles, CA, and it ended in Myrtle Beach, SC. Overall, his trip spanned 2,732.4 miles.
“This was accomplished with Tesla FSD V14.2 with absolutely 0 disengagements of any kind even for all parking including at Tesla Superchargers,” Moss stated in his post. He also added in later comments that there were zero close calls during the trip.
Tesla community celebrates
The FSD milestone trip was widely lauded by members of the Tesla community, especially since a coast-to-coast drive with zero interventions has been cited by Elon Musk as a target since October 2016, when Autopilot 2.0 was unveiled. At the time, Musk initially estimated that a coast-to-coast drive across the United States should be possible by the end of 2017. Considering Moss’ feat in his Model 3, it appears that Elon Musk’s estimate was not impossible at all. It was just late.
Musk himself celebrated the milestone on X, and so did Tesla VP of AI Software Ashok Elluswamy, who wrote “World’s first fully autonomous coast-to-coast drive, done with Tesla self-driving v14. Congrats and thank you @DavidMoss!” in a post on X. The official Tesla North America account also celebrated the feat, writing “First Tesla to drive itself from coast to coast w/ FSD Supervised. 0 interventions, all FSD” on X.
Elon Musk
Elon Musk: Tesla Model Y is world’s best-selling car for 3rd year in a row
The Model Y has now established an impressive streak that would otherwise have been impossible before Tesla.
Elon Musk has announced that the Tesla Model Y has become the world’s best-selling car by volume for the third consecutive year, capping 2025 with another dominant performance.
The Model Y has now established an impressive streak that would otherwise have been impossible before Tesla.
Three years in a row
Musk posted on X: “Tesla Model Y is now officially the world’s best-selling car for the third year in a row!” The CEO’s comment echoed an update that Tesla included in its 2025 recap, which highlighted, among other things, the Model Y’s incredible streak.
The Model Y has held the title since 2023, outperforming traditional leaders like the Toyota RAV4 and Corolla thanks to its bang-for-the-buck nature and its stellar combination of practicality, performance, and tech. The Model Y is also lauded as one of the safest vehicles on the road, making it an ideal choice for families in key markets such as China.
An impressive 2025
The Model Y’s sales feat in 2025 is especially impressive considering the introduction of the vehicle’s new variant. Tesla’s changeover to the new Model Y across its global factories resulted in sales being paused for some time in the first quarter. As per Tesla’s Q1 2025 vehicle delivery and production report, “the changeover of Model Y lines across all four of our factories led to the loss of several weeks of production in Q1.”
This suggests that the Model Y’s sales remained strong in 2025 to the point where it could still claim the title of the world’s best-selling vehicle by volume, even with its sales being throttled during the first quarter of the year. It would then be interesting to see just how far the Model Y can go in 2026, especially considering the rollout of new variants like the six-seat extended wheelbase Model Y L, the affordable Model Y Standard, and the top-tier Model Y Performance.
News
Tesla shares epic 2025 recap video, confirms start of Cybercab production
The cinematic montage, posted by the official Tesla account on X, celebrated the company’s progress in EVs, energy, and Robotaxi development.
Tesla has released an epic year-in-review video for 2025, recapping some of its major achievements from refreshed models to autonomy breakthroughs and production ramps.
The cinematic montage, posted by the official Tesla account on X, celebrated the company’s progress in EVs, energy, and Robotaxi development while looking ahead to an even bigger 2026.
Tesla’s 2025 highlights recap
Tesla has had a busy 2025, as highlighted in the recap video. The video opened with Elon Musk explaining the company’s pursuit of sustainable abundance. A number of milestones were then highlighted, such as the rollout of FSD v14, Optimus’ numerous demos, the opening of the Tesla Diner in Hollywood, LA, the completion of the world’s first autonomous car delivery, and the launch of the Robotaxi network in Austin and the San Francisco Bay Area.
Tesla also highlighted several of its accomplishments over the year. As per the company, the Model Y was the year’s best-selling vehicle globally again, and Teslas became more affordable than ever thanks to the Model 3 and Model Y Standard. Other key models were also rolled out, such as the refreshed Model S and X, as well as the new Model Y, the new Model Y Performance, and the six-seat, extended wheelbase Model Y L.
The Megablock was also unveiled during the year, and the Supercharger Network grew by 18%. Over 1 million Powerwalls were also installed during the year, and the Cybertruck became the first EV truck to get both an IIHS Top Safety Pick+ award and an NHTSA 5-Star safety rating.
Cybercab production confirmed
Interestingly enough, Tesla also confirmed in its 2025 recap video that the production of the Cybercab has started. This bodes well for the vehicle, as it could result in the vehicle really being mass-produced in the first half of 2026. Elon Musk confirmed during the 2025 Annual Shareholder Meeting that Cybercab production should earnestly start around April 2026.
Musk has also noted that the Cybercab will be Tesla’s highest-volume vehicle yet, with the company aiming for an annual production rate of about 2 million units. “If you’ve seen the design of the Cybercab line, it doesn’t look like a normal car manufacturing line,” Musk said earlier this year. “It looks like a really high-speed consumer electronics line. In fact, the line will move so fast that actually people can’t even get close to it.”
Tesla FSD successfully completes full coast-to-coast drive with zero interventions
Elon Musk: Tesla Model Y is world’s best-selling car for 3rd year in a row
