News
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 has apparently revised the policy it previously had listed for Full Self-Driving transfers on the newest All-Wheel-Drive Cybertruck that the company had sold for a steal price of just $59,000 earlier this year.
After initially stating that customers who bought the pickup would be able to transfer FSD purchases, Tesla recently changed the language in those terms and conditions to reflect that this would no longer be the case.
Tesla launches new Cybertruck trim with more features than ever for a low price
The adjustment in terminology has caused a handful of orderers to cancel their reservations due to the loss of FSD transfer:
Just cancelled my 59k CT order today. My screenshot from that day of order (feb 20th) clearly shows that it would be eligible.
Terms were retroactively modified. Our 2020 Y and 2023 S are just fine for now. pic.twitter.com/D9PFnId1B4
— Ryan Scanlan 👥 (@Xenius) June 8, 2026
Tesla said orders for the new Cybertruck AWD must be placed by March 31, 2026, to qualify for the FSD transfer. The language in the document from earlier this year explicitly states that they “may qualify” for the transfer program, but the date of March 31 is explicitly mentioned.
Additionally, Tesla Delivery Advisors reached out to some orderers of the AWD Cybertruck, who were told there was “an update to the eligibility of the Full Self-Driving (Supervised) transfer.” Tesla stated they could:
- proceed without the transfer,
- upgrade to a Premium or Cyberbeast trim and request an FSD Transfer
- cancel the order and be refunded the $250 order fee.
Tesla turning around and changing these terms will undoubtedly result in a handful of cancellations on the part of those who have placed an order for this truck. They could pay $99 per month for an FSD subscription, which is now the only option available, but having purchased the suite outright on another vehicle and being told the transfer policy would be upheld, only to have it cancelled, is a tough pill to swallow.
These moves were also made by Tesla just before deliveries were set to begin on the Cybertruck AWD configuration. Reservation holders have started receiving VINs for their trucks, and Tesla is preparing to hand over the first units.
It’s a disappointing move from Tesla that will undoubtedly make some of its fans who have bought the truck frustrated.
In the world of autonomous ride-hailing, there are only a handful of names. Among those few companies lies a strategy play by each to keep the opposition on their toes. Tesla, on the other hand, already tipped its hand at where it is headed next.
Tesla has signaled its next major push in the autonomous ride-hailing market by filing for an Autonomous Vehicle Network Company permit in Nevada (Docket 26-05015). Through Tesla Robotaxi, LLC, the company seeks approval to operate up to 5,000 robotaxis in Clark County, including high-traffic areas like Las Vegas and Henderson airports, within the first 12 months of launch.
This filing builds on Tesla’s earlier testing approvals from the Nevada DMV in September 2025 and preparations such as maintenance hubs in the Las Vegas area. Nevada represents a strategic expansion into a major tourist destination, where high visitor volumes could drive strong utilization and showcase the reliability of unsupervised autonomy to a broad audience.
We’d have to assume this means Tesla is targeting Las Vegas, and it’s a great move from a business perspective.
Vegas is such a melting pot of people from all around the country and the world. It will expose people from all corners of the globe to Tesla’s autonomy capabilities https://t.co/Qz3fQmhULF pic.twitter.com/Du5pj2RyWC
— TESLARATI (@Teslarati) June 6, 2026
Approval would mark a significant step toward commercial operations in a new state, following progress in Texas.
Tesla’s shareholder decks and earnings calls have clearly outlined these ambitions. In the Q4 2025 shareholder deck, the company listed planned Robotaxi coverage for the first half of 2026, explicitly naming Las Vegas alongside Phoenix, Miami, Orlando, and Tampa, with Dallas and Houston already advancing. Austin was noted as “ramping unsupervised,” while the Bay Area remained in safety-driver mode.
By Q1 2026, the deck updated statuses to reflect launches in Dallas and Houston, with “preparations underway” for the remaining cities, including Las Vegas. Paid Robotaxi miles nearly doubled sequentially in Q1, underscoring momentum even as broader timelines adjusted slightly for regulatory and operational readiness.
On earnings calls, CEO Elon Musk and executives have emphasized a phased rollout prioritizing safety. Unsupervised operations in Texas have shown strong results with no reported accidents or injuries in the program. Tesla continues groundwork in additional major U.S. metros through testing and permitting, positioning it to scale quickly once approvals clear.
This Nevada move aligns with Tesla’s vision of transforming from an EV maker into an AI and robotics leader. The forthcoming Cybercab, which started production at Giga Texas in April, is expected to eventually dominate the fleet, replacing many Model Y vehicles and driving down costs to enable affordable rides.
For investors and the industry, this signals Tesla’s intent to dominate key Sun Belt and tourist markets where weather, regulations, and demand favor rapid scaling. Success in Las Vegas could validate the model for denser urban and high-tourism environments, accelerating the shift toward a future where robotaxis generate meaningful revenue.
Las Vegas will also expand knowledge among the general public at Tesla’s capabilities, helping people experience driverless ride-hailing from several companies during their time on The Strip.
Investor's Corner
Tesla just did something in South Korea that no foreign carmaker has ever done
Tesla’s Model Y just became South Korea’s best-selling car, beating every domestic model in May.
Tesla did something last month that no foreign car has ever done in South Korea by outselling every vehicle in the country, domestic or imported, finishing the month with Model Y as the single best-selling car across the entire Korean market. According to data from the Korea Automobile Importers and Distributors Association released on June 4, the Model Y recorded 8,762 units sold in May, pushing the Kia Sorento into second place at 7,836 units and the Hyundai Grandeur into third at 5,183 units. It is the first time an imported vehicle has outsold every domestic model on a single-month basis.
Tesla imported 10,866 cars into South Korea in May, making it the top import brand for the fourth consecutive month. BMW followed at 6,555 units, less than two-thirds of Tesla’s total, while BYD registered just 1,032 units. The combined domestic sales of GM Korea, Renault Korea, and KG Mobility last month totaled just 7,019 units, meaning a single Tesla model outsold three Korean automakers combined.
Tesla FSD earns high praise in South Korea’s real-world autonomous driving test
South Korea has historically been one of the hardest markets for foreign automakers to crack. Hyundai and Kia together control close to 70% of the overall market and carry deep consumer loyalty built over decades. Tesla’s path into this market was an uphill battle due to high import duties, limited service infrastructure, and early skepticism about charging networks. In 2024, the Model Y was the best-selling imported car in South Korea with 18,717 units for the full year. By 2025, after the Juniper refresh, it cleared 50,000 units and took the top spot among all EVs.
Year to date, Tesla has a 250.8% increase in the country over the same period last year, and now holds a 30.8% share of the entire imported car segment for 2026. EVs as a category represented 48.6% of all imported passenger car registrations in May. As Teslarati has reported, the Juniper refresh brought meaningful improvements to range, interior quality, and ride refinement that addressed the most common criticisms of earlier Model Y versions. Those upgrades appear to be resonating in markets like South Korea where buyers compare Tesla directly against high end domestic competitors.
Tesla revises FSD transfer policy on new Cybertruck trim, causing cancellations
Tesla tipped its hand at where Robotaxi is heading next
