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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 is coming to Estonia and Latvia in latest European expansion: report
Tesla seems to be accelerating its regional expansion following its recent launch in Lithuania.
Recent reports have indicated that Tesla has taken a step toward entering the Baltic states by registering new subsidiaries in Latvia and Estonia.
Filings suggest that Tesla is accelerating its regional expansion following its recent launch in Lithuania, with service centers likely coming before full sales operations.
Official entities in Latvia and Estonia
Tesla has established two new legal entities, Tesla Latvia SIA and Tesla Estonia OÜ, both owned by Tesla International B.V., as noted in an EV Wire report. Corporate records show the Estonian entity was formed on December 16, 2025, while the Latvian subsidiary was registered earlier, on November 7.
Both entities list senior Tesla executives on their boards, including regional and finance leadership responsible for new market expansion across Europe. Importantly, the entities are registered under “repair and maintenance of motor vehicles,” rather than strictly vehicle sales. This suggests that Tesla service centers will likely be launched in both countries.
The move mirrors Tesla’s recent Baltic rollout strategy. When Tesla entered Lithuania, it first established a local entity, followed by a pop-up store within weeks and a permanent service center a few months later. It would then not be surprising if Tesla follows a similar strategy in Estonia and Latvia, and service and retail operations arrive in the first half of 2026.
Tesla’s European push
Tesla saw a drop in sales in Europe in 2025, though the company is currently attempting to push more sales in the region by introducing its most affordable vehicles yet, the Model 3 Standard and the Model Y Standard. Both vehicles effectively lower the price of entry into the Tesla ecosystem, which may make them attractive to consumers.
Tesla is also hard at work in its efforts to get FSD approved for the region. In the fourth quarter of 2025, Tesla rolled out an FSD ride-along program in several European countries, allowing consumers to experience the capabilities of FSD firsthand. In early December, reports emerged indicating that the FSD ride-along program would be extended in several European territories until the end of March 2026.
Elon Musk
Elon Musk’s X will start using a Tesla-like software update strategy
The initiative seems designed to accelerate updates to the social media platform, while maintaining maximum transparency.
Elon Musk’s social media platform X will adopt a Tesla-esque approach to software updates for its algorithm.
The initiative seems designed to accelerate updates to the social media platform, while maintaining maximum transparency.
X’s updates to its updates
As per Musk in a post on X, the social media company will be making a new algorithm to determine what organic and advertising posts are recommended to users. These updates would then be repeated every four weeks.
“We will make the new 𝕏 algorithm, including all code used to determine what organic and advertising posts are recommended to users, open source in 7 days. This will be repeated every 4 weeks, with comprehensive developer notes, to help you understand what changed,” Musk wrote in his post.
The initiative somewhat mirrors Tesla’s over-the-air update model, where vehicle software is regularly refined and pushed to users with detailed release notes. This should allow users to better understand the details of X’s every update and foster a healthy feedback loop for the social media platform.
xAI and X
X, formerly Twitter, has been acquired by Elon Musk’s artificial intelligence startup, xAI last year. Since then, xAI has seen a rapid rise in valuation. Following the company’s the company’s upsized $20 billion Series E funding round, estimates now suggest that xAI is worth tens about $230 to $235 billion. That’s several times larger than Tesla when Elon Musk received his controversial 2018 CEO Performance Award.
As per xAI, the Series E funding round attracted a diverse group of investors, including Valor Equity Partners, Stepstone Group, Fidelity Management & Research Company, Qatar Investment Authority, MGX, and Baron Capital Group, among others. Strategic partners NVIDIA and Cisco Investments also continued support for building the world’s largest GPU clusters.
News
Tesla FSD Supervised wins MotorTrend’s Best Driver Assistance Award
The decision marks a notable reversal for the publication from prior years, with judges citing major real-world improvements that pushed Tesla’s latest FSD software ahead of every competing ADAS system.
Tesla’s Full Self-Driving (Supervised) system has been named the best driver-assistance technology on the market, earning top honors at the 2026 MotorTrend Best Tech Awards.
The decision marks a notable reversal for the publication from prior years, with judges citing major real-world improvements that pushed Tesla’s latest FSD software ahead of every competing ADAS system. And it wasn’t even close.
MotorTrend reverses course
MotorTrend awarded Tesla FSD (Supervised) its 2026 Best Tech Driver Assistance title after extensive testing of the latest v14 software. The publication acknowledged that it had previously criticized earlier versions of FSD for erratic behavior and near-miss incidents, ultimately favoring rivals such as GM’s Super Cruise in earlier evaluations.
According to MotorTrend, the newest iteration of FSD resolved many of those shortcomings. Testers said v14 showed far smoother behavior in complex urban scenarios, including unprotected left turns, traffic circles, emergency vehicles, and dense city streets. While the system still requires constant driver supervision, judges concluded that no other advanced driver-assistance system currently matches its breadth of capability.
Unlike rival systems that rely on combinations of cameras, radar, lidar, and mapped highways, Tesla’s FSD operates using a camera-only approach and is capable of driving on city streets, rural roads, and freeways. MotorTrend stated that pure utility, the ability to handle nearly all road types, ultimately separated FSD from competitors like Ford BlueCruise, GM Super Cruise, and BMW’s Highway Assistant.
High cost and high capability
MotorTrend also addressed FSD’s pricing, which remains significantly higher than rival systems. Tesla currently charges $8,000 for a one-time purchase or $99 per month for a subscription, compared with far lower upfront and subscription costs from other automakers. The publication noted that the premium is justified given FSD’s unmatched scope and continuous software evolution.
Safety remained a central focus of the evaluation. While testers reported collision-free operation over thousands of miles, they noted ongoing concerns around FSD’s configurable driving modes, including options that allow aggressive driving and speeds beyond posted limits. MotorTrend emphasized that, like all Level 2 systems, FSD still depends on a fully attentive human driver at all times.
Despite those caveats, the publication concluded that Tesla’s rapid software progress fundamentally reshaped the competitive landscape. For drivers seeking the most capable hands-on driver-assistance system available today, MotorTrend concluded Tesla FSD (Supervised) now stands alone at the top.
Tesla is coming to Estonia and Latvia in latest European expansion: report
Elon Musk’s X will start using a Tesla-like software update strategy
