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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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Tesla adjusts Online Design Studio for easier trade-in process
Tesla has a great trade-in program that allows you to give the company your vehicle in exchange for cash, even if it’s not an EV. Their trades are mostly fair, but the company seems to undervalue its own vehicles, and there have been plenty of complaints over offers in the past.
Tesla has adjusted its Online Design Studio to make for an easier trade-in process, reflecting the details of the exchange for a more accurate reflection of payment terms.
Tesla has a great trade-in program that allows you to give the company your vehicle in exchange for cash, even if it’s not an EV. Their trades are mostly fair, but the company seems to undervalue its own vehicles, and there have been plenty of complaints over offers in the past.
Trade-ins are usually given by submitting vehicle details, then Tesla sends an email with an offer. Offers are non-negotiable, but do adjust over time, although the latest offer is valid for 30 days.
I traded my ICE vehicle for a Tesla Model Y: here’s how it went
Knowing your new Tesla’s cash price, leasing or loan details, and monthly payment information used to be done by the car buyer. From personal experience, I simply subtracted my trade-in from the cash price of the Tesla Model Y, and I plugged those numbers into the payment calculator.
Now, Tesla is implementing the trade-in process directly into the Design Studio. It will adjust the price of the car and the different monthly payment methods automatically:
Trade-in estimates available directly on our configurator in few states including CA, will cover all of US and Canada next week.
For loyalty customers, if their trade-in VIN is eligible for any loyalty credit, the same will be applied to the estimate. pic.twitter.com/7097vPleMf
— Raj Jegannathan (@r_jegaa) November 8, 2025
The change is already noticed in a handful of states, including California, but it has not rolled out across the board quite yet. It will be implemented in all of the U.S., as well as Canada, this coming week.
The trade-in process is very simple, and after you accept your offer, you simply drop your vehicle off during the delivery process. Making this simple change will be greatly appreciated by owners.
News
Tesla confirms Robotaxi is heading to five new cities in the U.S.
After launching in Austin, Texas, in late June and the Bay Area of California just a few weeks later, Tesla has been attempting to expand its Robotaxi suite to new states and cities in the U.S., and even outside of the country.
Tesla Robotaxi will hit five new cities in the United States in the coming months, the company confirmed.
After launching in Austin, Texas, in late June and the Bay Area of California just a few weeks later, Tesla has been attempting to expand its Robotaxi suite to new states and cities in the U.S., and even outside of the country.
The Robotaxi suite is a ride-hailing service Tesla offers, but the details of it change with each jurisdiction, as regulations vary. For example, in Austin, Tesla can operate the Robotaxi suite without anyone in the driver’s seat, as long as the vehicle does not enter a freeway.

Credit: Tesla
In the Bay Area, a Safety Monitor rides in the driver’s seat, essentially acting as the vehicle operator with Full Self-Driving controlling the car.
The local regulations and how Tesla handles them will continue to be a relevant part of the discussion, especially as the company aims to expand the Robotaxi program to different areas. This has been a primary focus of the company for several months, especially within the United States.
CEO Elon Musk said that Tesla was aiming to launch Robotaxi in Nevada, Arizona, and Florida. However, the company detailed five specific cities where it will launch Robotaxi next during the Annual Shareholder Meeting on Thursday.
Tesla will launch Robotaxi in Las Vegas, Phoenix, Dallas, Houston, and Miami next, broadening its Service Area for the suite to more major cities across the U.S.
It has said it plans to offer the service to half of the U.S. population by the end of the year, but it does not seem as if it will expand to more than a handful of cities this year, which is still tremendous progress, all things considered.
As far as autonomy is concerned, Tesla has always had lofty expectations and has made some even loftier statements.
At the Shareholder Meeting, Musk said that the company would likely be able to enable vehicle owners to text while the vehicle drives, alleviating them from potentially having some of the responsibility they have behind the wheel.
Tesla says texting and driving capability is coming ‘in a month or two’
It is not confirmed that Tesla will roll this out in the next few months, but Musk said there is a possibility.
News
Tesla launches another new Model Y trim at a bargain price with massive range
It is the second most-affordable Model Y trim level in China, trailing the base Rear-Wheel-Drive and coming in under the All-Wheel-Drive.
Tesla has launched yet another new Model Y trim level, but this time it is in China, and it is at a bargain price.
It also has an insane range rating.
On Friday, Tesla launched the new Model Y Long Range Rear-Wheel-Drive in China, priced at 288,500 yuan ($40,500), an incredible deal considering it is not a stripped-down version of the vehicle like the Model Y Standard.
🚨🚨 Tesla’s new China-launched Model Y LR RWD offers 821 km (510 miles) CLTC range with 78.4 kWh CATL battery, beating AWD’s 750 km.
At 288,500 yuan ($40,500 USD), it fits between base RWD (593 km, 263,500 yuan) and AWD (313,500 yuan) for affordable long-range EVs.
CLTC… https://t.co/rhKVzvUWlu pic.twitter.com/ZOoelziJ8T
— TESLARATI (@Teslarati) November 8, 2025
It is the second most-affordable Model Y trim level in China, trailing the base Rear-Wheel-Drive and coming in under the All-Wheel-Drive.
The big appeal with this new Model Y trim is obviously its price, but its range rating is also one of the best we’ve seen. Rated at 821 kilometers on the CLTC scale, it converts to 510 miles. It uses a 78.4 kWh CATL battery.
Converted to real-world range, however, that 821-kilometer range rated by the CLTC actually is equivalent to about 357 miles on the EPA scale, which is still a very respectable number and comes in at a higher range than the Long Range All-Wheel-Drive configuration that is available in the U.S.
Tesla has truly brought a wide variety of Model Y trims to the Chinese market, including a new Model Y L configuration that features a slightly longer wheelbase, as well as additional interior features like extended thigh legrests and captain’s chairs with armrests.
It is unclear whether Tesla will bring a Premium Rear-Wheel-Drive option of the Model Y to the U.S., especially as it has already rolled out four configurations of the all-electric crossover in the market. With the new Standard offerings, Tesla will likely keep its lineup as simple as possible.
However, the company has hinted that there is a slim possibility the Model Y L could come to the U.S. sometime late next year, but CEO Elon Musk said that it is not a guarantee.
Tesla is more concerned with self-driving efforts in the U.S., and despite calls from customers for larger vehicles, it does not seem concerned with making them available, at least not for now.
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