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 launched the all-electric, steering wheel-less, and pedal-less Cybercab last night at a quiet and small event in downtown Austin, Texas.
The launch, which marked the beginning of unsupervised ride-hailing for Tesla’s Robotaxi platform with Cybercab, has already caught the attention of the National Highway Traffic Safety Administration (NHTSA) who has more questions.
NHTSA opened an Audit Query (AQ) into the Cybercab’s Federal Motor Vehicle Safety Standards (FMVSS) certification that Tesla gave the vehicle. Manufacturers self-certify vehicles much of the time to avoid excessive regulatory delays.
Tesla Cybercab interior, note the lack of steering wheel and pedals. (Credit: @niccruzpatane/X< /a>)
However, the agency needs more information; it said in a summary:
“On September 3, 2026, Tesla began commercial deployment with a small number of its Cybercab vehicles in Austin, Texas. Tesla notified the Agency that it certified those Cybercab vehicles as compliant with all applicable Federal Motor Vehicle Safety Standards (FMVSS). Tesla also notified the Agency that it plans to gradually expand commercial deployment of the Cybercab to include additional vehicles and locations.”
It also went on to state that the Cybercab lacks traditional automotive controls, which is a groundbreaking move. The process is entirely new to the NHTSA, which gives the agency some leverage to put Tesla’s launch under a microscope:
“The vehicles lack permanently attached, conventional manual controls, such as a brake pedal, gas pedal, steering wheel, and mirrors. NHTSA is opening this AQ to examine the process and technical data on which Tesla relied when certifying the Cybercab and related issues. Among other things, NHTSA will consider the extent to which Tesla’s certification depended on determinations that certain FMVSS are inapplicable to the Cybercab.”
Tesla has added 45 Cybercab units to its fleet of Robotaxi-enabled cars in Austin, according to public documents the company submitted to the State of Texas over the past week. Enabling this level of self-driving is something Tesla has worked toward for many years, and now that it is finally here, it seems more than reasonable that regulatory agencies will have some questions.
Many outlets might try to frame this as a negative, but it is truly an agency looking to gain more information about groundbreaking tech that Tesla has been developing for years.
In an effort to keep riders, pedestrians, and property safe, any and all data accumulated from these first days, weeks, and months of rides will likely be shared with the NHTSA to enable broader rollout strategies across the United States and more in the future.
Featured
Tesla Cybercab is coming to Asia this month as US service officially begins
Tesla Asia says Cybercab will be on display in Hong Kong, Tokyo, Beijing and Shanghai this month.
Tesla’s Cybercab is heading to Asia. The official Tesla Asia account posted on X Thursday, inviting Cybercab fans to “Come experience the future of autonomy in Hong Kong, Tokyo, Beijing & Shanghai.” The post went up within hours of Tesla’s own Cybercab milestone in Texas, where the company said Thursday it had begun offering rides in across Austin.
Exact dates and venues for the Asia tour haven’t been released yet, though Tesla Hong Kong replied to the announcement with “Cybercab will be on display in Hong Kong soon,” while Tesla Japan’s response pointed fans to a sign up page for updates. Neither post mentions test rides or a service area, and nothing so far suggests Tesla is launching Robotaxi operations in any of the four cities. Based on how Tesla has run past Cybercab tours, in Europe in late 2024 and at US shopping centers that same December, the Asia stops are almost certainly static displays at Tesla stores or public venues as a means to stimulate buzz for its future driverless ride-hailing service in the big cities.
Cybercab will be on display in Asia this month!
Come experience the future of autonomy in Hong Kong, Tokyo, Beijing & Shanghai. pic.twitter.com/wGmmEastfX— Tesla Asia (@Tesla_Asia) September 4, 2026
The timing lines up with Tesla’s only prior Cybercab appearance in the region, a booth at the China International Import Expo in Shanghai last November, which Teslarati covered at the time. At that event, Tesla’s regional general manager for Shanghai framed the car as evidence of the company’s broader mission, a message Tesla has since formalized in its Master Plan Part IV, which states that “autonomous vehicles have the capacity to dramatically improve the affordability, availability and safety of transportation while reducing pollution, particularly in our increasingly dense global cities.” The same document is where Tesla lays out its “sustainable abundance” framing for Cybercab and Optimus alike, describing the two as the hardware behind an AI driven push to cut the cost of transportation and labor at scale.
Whether Cybercab actually operates as a robotaxi anywhere in Asia remains an open question, considering China has already pushed an autonomous ride-hailing market that’s run on homegrown players like Baidu’s Apollo Go and Pony AI. For now, the four city tour reads as a marketing push timed to Austin’s momentum.
Lifestyle
Tesla Cybertruck targets job site crews with new Tailgate Utility Track and Bed Gear Box accessory
Tesla launched a $350 tailgate track and a $985 lockable Bed Gear Box for Cybertruck.
Tesla’s Cybertruck team added two more items to the Tesla Shop, targeting job site crews and owners who use the truck bed for actual work rather than just showing it off. The official Cybertruck X account posted the Tailgate Utility Track and the Bed Gear Box within minutes of each other, part of a five item batch that also included a reflective jacket, a spray paint hat and an updated reflective tee.
The Tailgate Utility Track runs $350 and turns the folded down tailgate into another mounting surface. It’s a single aluminum track with a T-slot for sliding accessories and two L-track attachment points, plus two load stops included in the box. The pitch is straightforward: strap down oversized cargo, like lumber or a cooler, that hangs off the back of the bed without it sliding out mid-drive. It bolts onto the existing tailgate and works on every Cybertruck trim.
Tailgate Utility Trackhttps://t.co/PCAYXlFBvS pic.twitter.com/sCV2NVxf1W
— Cybertruck (@cybertruck) September 3, 2026
The Bed Gear Box costs $985 and is a different kind of accessory. It’s a lockable aluminum storage box, 55.78 inches long, 19.8 inches wide and 7.79 inches tall, that mounts to the bed’s L-track rails and comes with two internal bins for smaller items. According to Tesla, at just over 57 pounds empty, it’s meant to stay in place rather than come in and out with each trip, giving owners a factory-fit alternative to loose totes for tools, recovery gear or emergency supplies. Tesla’s listing notes that Long Range and Dual Motor AWD Cybertrucks need the L-Tracks accessory installed separately before the Gear Box will mount, since L-tracks come standard only on certain configurations.
Tesla Cybertruck bed gear box accessory
Both accessories lean on the idea Tesla has been building toward since Elon Musk first described the Cybertruck’s third-party attachment strategy at the 2023 shareholder meeting, when he said the truck would ship with mounting points so outside companies, and Tesla itself, could keep adding gear without redesigning the bed. That’s the same L-track backbone underneath the tailgate shield and jumpseats Tesla launched last year, and the off-road armor package that arrived through the same X account in 2025.
Owners looking to round out the rest of the L-track ecosystem, cargo dividers, MOLLE panels, bed racks and similar gear, can find a wider range of options through our Cybertruck accessories collection.
Tesla Cybercab launch catches NHTSA’s attention who wants to know more
Tesla Cybercab is coming to Asia this month as US service officially begins
