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.
I’d love to hear from you! If you have any comments, concerns, or questions, please email me at joey@teslarati.com. You can also reach me on Twitter @KlenderJoey, or if you have news tips, you can email us at tips@teslarati.com.
Tesla Cybercab is using a unique strategy for picking up the correct rider, which is a crucial part of ride-hailing to ensure people end up in the right place and are charged the correct price.
Cybercab will utilize an RGB strip in its front light bar that will illuminate in a variety of different colors to mark itself.
This identifying mark will also appear in the Robotaxi app, giving riders in the same location a notable distinction in an effort to avoid any confusion regarding who should get in each vehicle.
🚨 Tesla is using different light bar colors to help riders understand which vehicle is theirs
Pretty cool strategy pic.twitter.com/eGMpEMeRpc
— TESLARATI (@Teslarati) August 27, 2026
Other ride-hailing services use similar strategies: Lyft and Uber rides are recognizable through driver identity, vehicle type and color, as well as license plate. Waymo will display the rider’s initials on top of the vehicle, letting them know that the specific vehicle for them has arrived.
Tesla’s strategy is unique and interesting, but there are some flaws. Cybercab’s main purpose is aimed toward being an autonomous ride for all, including those who have disabilities like being blind or even color blind.
Tesla will likely have something in the pipeline for those who cannot see colors or have limited vision. There will definitely be multiple ways to identify which vehicle is the one that “you” specifically ordered.
Cybercab is set to start giving public rides next Thursday, September 3, in Austin, as it announced a dedicated event last week and invited many members of the Tesla community.
Additionally, members of the public will be invited as well. Tesla has been offering employee rides in Cybercab for nearly two months.
Tesla has said goodbye to one customization option for its vehicles: the wrap service it launched several years ago.
After launching an in-house wrap service in August 2020 for the first time in China. In the U.S., it launched in October 2023. Tesla continued to expand the program and adjust it with better pricing and fewer options for the Cybertruck.
By December 2023, it was giving owners of the Model 3, Model Y, and the Cybertruck the opportunity to give their vehicle a fresh look with a vinyl wrap.
Tesla revamps in-house vinyl wrap service with better pricing
It was only available in five locations: Costa Mesa, Oceanside, Santa Clara, West Covina, all in California, and Seattle, Washington.
However, Tesla made some big adjustments to its shop, and the wrap service is officially gone:
Tesla has made a LOT of changes to its online shop recently — price increases, price cuts, new options, and several products being removed entirely.
Some of the biggest increases are wheel covers. 👀
📈 PRICE INCREASES
• 2017-2023 | Model 3 Aero Wheel Cover — Style: Refresh…— Phoenix Self-Driving 🐦🔥 (@PhoenixFSD) August 25, 2026
Wraps are very popular across the Tesla lineup, especially since the company offers relatively few colors. Many choose to wrap their Teslas with interesting colors, patterns, or even finishes, turning their cars from glossy to satin or matte.
However, Tesla’s wrap service was so limited geographically that it never really had a chance to get off the ground or compete with local shops. Every area in the United States is now overflowing with detailing shops, mobile detailers, and other automotive specialists, many of whom perform wrap services.
Tesla’s service was confined to the Pacific time zone and only spanned across two states. It was never going to be something Tesla was a major competitor in, nor was it going to disrupt the wrapping industry. Now that the program has ended, it seems pretty ideal to believe it was always going to be a short-term thing.
Along with the wrap service, Tesla removed several other products, but nothing too crazy. The Model 3 Door Pocket and Cupholder Liners, the Model S 19″ Magnetite Wheel and Winter Tire Package, Model X/Y Ski/Snowboard Carrier for Hitch Rack, Tesla’s Electric Summer Party Tee, and the Electric Summer Tee were the other items the company totally eliminated from its online shop.
News
Tesla Robotaxi fleet gets a brain upgrade ahead of Cybercab launch event
Tesla’s Robotaxi service now runs longer hours nationwide as its unsupervised fleet quietly grows larger.
Tesla’s Robotaxi service just got easier to catch, with the company’s official Robotaxi account noting that rides are now available from 6 a.m. to 10 p.m., seven days a week, across its operating footprint. The account also said its unsupervised fleet is “a lot bigger” than before, though without specifics. The bigger change is what Tesla says upgraded intelligence in vehicle distribution and routing is what’s actually cutting wait times, not a new Full Self-Driving version.
While Tesla did not name the team behind the upgrade, the language points to its AI and fleet software group rather than the driving stack itself. Vehicle distribution and routing in Robotaxi has functioned mostly as a dispatch problem with the software deciding which idle car goes to which rider, and how far it has to travel to get there. “Upgraded intelligence” suggests a smarter version of that dispatch logic, likely using demand forecasting to position idle cars near where riders are about to request them rather than reacting once a request comes in. Tesla’s AI division has built similar prediction systems for other parts of the business, including the neural networks that power FSD itself, so applying that same approach to fleet logistics would be a natural extension rather than a new discipline for the team.
Robotaxi now runs 6am to 10pm, 7 days/week
Unsupervised fleet is a lot bigger
Also, upgraded intelligence in vehicle distribution & routing means you wait less pic.twitter.com/UFZ4bqg2dZ
— Tesla Robotaxi (@robotaxi) August 26, 2026
Tesla is also about a week away from a separate robotaxi milestone. The company plans to launch Cybercab, its purpose built two seat robotaxi with no steering wheel or pedals, in Austin on September 3. Cybercab has been giving employees rides on public and private roads for weeks, and the September event is expected to fold those vehicles into the existing Robotaxi fleet within days of the launch.
Thank you so much @Tesla for inviting us to the Cybercab launch in Austin! 🤠 pic.twitter.com/F1rAR8zd5O
— TESLARATI (@Teslarati) August 22, 2026
Austin previously ran Robotaxi from 6 a.m. to 2 a.m. as of last September, a schedule set before the service expanded into Dallas, Houston, Miami, Tampa, Orlando and the Bay Area. Wednesday’s post did not specify whether that extended overnight window still applies in Austin specifically or whether 6 a.m. to 10 p.m. is now the standard across every market. Tesla’s post, visible on its official Robotaxi account, framed the change simply as fewer riders waiting around for a car.
Whether the wider hours hold once Cybercab enters the fleet next week is the next thing worth watching. Tesla has tended to expand Robotaxi in increments, first geofence, then hours, then fleet size, and each step so far has arrived without much advance notice.
Tesla Cybercab uses a unique strategy for picking up the right rider
Tesla ends in-house wrap service that always seemed like a short-term program
