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.
The in-car Tesla Theater is among the most unique features available within the cars. When charging, parked, camping, or just hanging out, vehicle occupants can access a variety of streaming platforms on the large center screen, helping keep them entertained during downtime.
However, the Theater might be getting plenty more streaming platforms, something that owners have requested for some time.
Tesla owners recently discovered that visiting Apple TV in the vehicle browser can launch a fullscreen interface that looks and behaves like a dedicated application rather than an ordinary webpage:
Today I learned that if you go to Apple TV in the Tesla browser, it will open up an actual Apple TV app, fully functional. Not just the site.
Apparently there are more apps than just the few that show on the apps page. pic.twitter.com/os1Ypfm4JR
— Jason W (@jmwilt21) August 20, 2026
The experience drops the usual address bar and browser chrome, presenting catalogs, continue watching rows, and playback controls in the same window Tesla Theater already uses for its listed services. Independent testers soon found similar treatment for HBO Max, Paramount+, Peacock, Disney+, and Prime Video when those sites are opened from the car browser.
This shift is a plausible early signal that Tesla is widening Theater support without a formal software note. Theater has long been a set of web views rather than native applications, so recognizing extra domains and stripping the browser frame is a small server-side change that can expand the catalog quickly.
Owners still lack permanent Theater icons for the newly recognized services, and video remains limited to Park, yet the smoother launch is a meaningful step toward a broader lounge while charging.
Tesla Theater arrived with software version 10 in September 2019. The first video services were Netflix, YouTube, and Hulu, available only while parked and originally tied to WiFi. Spotify arrived in the same era as music rather than Theater video. Disney+ joined officially in July 2021 with the 2021.24 update, giving owners another major catalog on the center screen. Twitch and TikTok later appeared among the default Theater tiles, and Tesla Tutorials remained a persistent educational tile.
Not every addition stayed put. In December 2023, a Holiday software build removed the Disney+ tile for many United States owners after a public dispute involving advertising on X. Hulu stayed visible even though Disney owned it. Visiting disneyplus.com in the browser often restored the tile, which suggested the removal was a recognition list change rather than a complete block. Owners have also reported occasional blank Theater grids after updates, usually fixed by language toggles, resets, or later firmware.
Tesla axes Disney+ from vehicles with Musk-Iger rivalry, but there’s a workaround
Code archives from 2024 listed many unused source names, including Apple TV and Prime Video, that never became official icons, which now looks like groundwork for the current fullscreen browser behavior.
Now that this hint toward an expanded Theater experience has been recognized, Tesla could follow through with these additional shortcuts as a sign that more streaming platforms are available in Teslas than ever before.
Tesla recently received its largest order for the all-electric Semi from Einride, a Swedish transport service, for 500 units, a groundbreaking invoice to receive before the first deliveries begin.
Even more remarkable, Einride CEO Roozbeh Charli said in a recent interview that he expects his company to take delivery of all 500 — the entire order — before the end of 2027. He even expects to have 75 Tesla Semi units in the Einride fleet before the end of this year.
🚨 Einride CEO Roozbeh Charli on the Tesla Semi partnership:
“If we start with the Amazon announcement that we did earlier this year, that was on the back of having gone through a proving period together with them and proving out our technology. Then we took that next step in… pic.twitter.com/oazkXjwoig
— TESLARATI (@Teslarati) August 28, 2026
Charli said the Tesla partnership was part of a broader push, along with its earlier partnership with Amazon. Einride is assisting Amazon with the use of its Saga AI platform, which helps eliminate questions about budgeting and forecasting for logistics companies.
The Semi, as well as Tesla’s production and subsequent delivery of the units to Einride, will help the company “to have a good supply of vehicles that we can deploy on the [Saga AI] platform,” Charli said. “Tesla is also a relationship we’ve had for a while, and as the Tesla Semi deliveries are firming up, we decided to do a larger commitment to that and deploy that on our platform.”
In its initial announcement, Einride said it anticipated taking delivery of the trucks over the next two years, but now it appears the company is expecting all 500 units within the next 16 months.
Built at a dedicated factory in Sparks, Nevada, the Tesla Semi has been perhaps the biggest and most intensive testing process the company has ever had for a single vehicle model. For the past several years, Tesla has been working with many companies, most notably Frito-Lay and PepsiCo, to gain knowledge on the performance on regional routes.
Tesla plans to launch the Semi officially on September 24, five months after production started ramping.
Additionally, drivers have said they are happy about the Semi’s performance and that its numerous safety and productivity features have made their jobs and routes much easier.
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 Theater might be getting plenty more streaming platforms
Tesla Semi’s biggest adoptee gives an update on production timeline
