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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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Tesla Model 3 and Model Y earn Euro NCAP Best in Class safety awards
“The company’s best-selling Model Y proved the gold standard for small SUVs,” Euro NCAP noted.
Tesla won dual categories in the Euro NCAP Best in Class awards, with the Model 3 being named the safest Large Family Car and the Model Y being recognized as the safest Small SUV.
The feat was highlighted by Tesla Europe & Middle East in a post on its official account on social media platform X.
Model 3 and Model Y lead their respective segments
As per a press release from the Euro NCAP, the organization’s Best in Class designation is based on a weighted assessment of four key areas: Adult Occupant, Child Occupant, Vulnerable Road User, and Safety Assist. Only vehicles that achieved a 5-star Euro NCAP rating and were evaluated with standard safety equipment are eligible for the award.
Euro NCAP noted that the updated Tesla Model 3 performed particularly well in Child Occupant protection, while its Safety Assist score reflected Tesla’s ongoing improvements to driver-assistance systems. The Model Y similarly stood out in Child Occupant protection and Safety Assist, reinforcing Tesla’s dual-category win.
“The company’s best-selling Model Y proved the gold standard for small SUVs,” Euro NCAP noted.
Euro NCAP leadership shares insights
Euro NCAP Secretary General Dr. Michiel van Ratingen said the organization’s Best in Class awards are designed to help consumers identify the safest vehicles over the past year.
Van Ratingen noted that 2025 was Euro NCAP’s busiest year to date, with more vehicles tested than ever before, amid a growing variety of electric cars and increasingly sophisticated safety systems. While the Mercedes-Benz CLA ultimately earned the title of Best Performer of 2025, he emphasized that Tesla finished only fractionally behind in the overall rankings.
“It was a close-run competition,” van Ratingen said. “Tesla was only fractionally behind, and new entrants like firefly and Leapmotor show how global competition continues to grow, which can only be a good thing for consumers who value safety as much as style, practicality, driving performance, and running costs from their next car.”
News
Tesla is shifting FSD to a subscription-only model, confirms Elon Musk
Tesla CEO Elon Musk confirmed the upcoming update in a post on social media platform X.
Tesla will be ending one-time purchases of its Full Self-Driving (FSD) system after Valentine’s Day, transitioning the feature to a monthly subscription-only model.
Tesla CEO Elon Musk confirmed the upcoming update in a post on social media platform X.
No more FSD one-time purchases
As per Elon Musk in his post on X, “Tesla will stop selling FSD after Feb 14. FSD will only be available as a monthly subscription thereafter.” This marks a shift in how Tesla monetizes its FSD system, which can now be purchased for a one-time fee or accessed through a monthly subscription.
FSD’s subscription model has been $99 per month in the United States, while its one-time purchase option is currently priced at $8,000. FSD’s one-time purchase price has swung wildly in recent years, reaching $15,000 in September 2022. At the time, FSD was proficient, but its performance was not on par with v14. This made its $15,000 upfront price a hard sell for consumers.
Tesla’s move to a subscription-only model could then streamline how the company sells FSD. It also lowers the entry price for the system, as even price-conscious drivers would likely be able to justify FSD’s $99 monthly subscription cost during periods when long-distance travel is prevalent, like the holidays.
Musk’s compensation plan and FSD subscription targets
Tesla’s shift to a subscription-only FSD model comes amidst Musk’s 2025 CEO Performance Award, which was approved by Tesla shareholders at the 2025 Annual Shareholders Meeting with roughly 75% support. Under the long-term compensation plan, Musk must achieve a series of ambitious operational milestones, including 10 million active FSD subscriptions, over the next decade for his stock awards to vest.
The 2025 CEO Performance Award’s structure ties Musk’s potential compensation to Tesla’s aggressive targets that span market capitalization, vehicle deliveries, robotics, and software adoption. Apart from his 10-million active FSD subscription target, Musk’s compensation is also tied to Tesla producing 20 million vehicles cumulatively, delivering 1 million Tesla bots, and having 1 million Robotaxis in operation. He must also lead Tesla to a market cap of $8.5 trillion.
If successful, Elon Musk’s 2025 CEO Performance Award could make him the world’s first trillionaire. It could also help Tesla become the world’s most valuable company by market cap by a notable margin.
Tesla is planning for a new 300+ stall Supercharger station that will be an expansion of an existing facility, and the company is planning to add a surprise for the Semi.
The Firebaugh, California Supercharger is currently 72 Superchargers, but Tesla filed for an expansion that will add 232 additional plugs for passenger vehicles, and it also plans to add 16 Semichargers.
This will be the biggest Supercharger station Tesla will have to date, just months after it finished the Supercharger Oasis in Lost Hills, California, which has 168 stalls. This will have 304 total Supercharger stalls, and then the additional 16 Megachargers.
🚨 This Supercharger station will have 304 total stalls and 16 Semichargers following this expansion
Absolutely INSANE size 🔥
This is located on I-5, so many semis will be traveling along this route https://t.co/hM9hdLcWwg
— TESLARATI (@Teslarati) January 13, 2026
The Firebaugh Supercharger is located on I-5, which is a major reason for why Tesla has chosen the location for additional Megacharger plug-ins, as Tesla Semi Program Manager Dan Priestley said on X earlier today.
Lots of trucks to electrify on I-5
— Dan Priestley (@danWpriestley) January 13, 2026
The project was revealed by MarcoRP, a Supercharger tracker.
The expansion is a massive signal for charging demand, especially as Tesla’s Superchargers are opened to numerous automakers and are no longer exclusive to the company’s EVs. Additionally, the installation of Megachargers is a good sign to come for the Tesla Semi program, which aims to truly ramp up this year.
Tesla plans to launch production of the Semi later this year.
It could also mean Tesla is going to expand its footprint of large-scale Supercharger projects in the coming years, which would be a big boost as EV adoption continues to soar in the United States.
Tesla Model 3 and Model Y earn Euro NCAP Best in Class safety awards
Tesla is shifting FSD to a subscription-only model, confirms Elon Musk
