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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 has upgraded the Model Y’s two most affordable trims, the Rear-Wheel-Drive and All-Wheel-Drive, with two new interior features that bring them level with their “Premium” siblings.
The Rear-Wheel-Drive (RWD) and All-Wheel-Drive (AWD) trims, formerly known as the “Standard” offerings of Tesla’s most popular vehicle, are now fitted with the all-black headliner and a higher-quality 16-inch center screen, two features that were added to the Premium trims earlier this year.
Here’s what the new Black Headliner looks like compared to the old design in the Model Y RWD and AWD: https://t.co/vaMUZz30UC pic.twitter.com/i1yXjJNu7L
— TESLARATI (@Teslarati) June 5, 2026
The RWD and AWD trims of the Model Y now have a more premium interior feel with these upgrades, and it also appears to be a move by Tesla to streamline manufacturing by eliminating variance across configuration levels.
It makes production less complicated when the interior colors are all identical. Additionally, all Model Y builds now have the larger and higher-resolution screen than previous model years.
Priced at $39,990 and $41,990, respectively, the Model Y RWD and AWD are quite different from the Premium trims. Tesla aimed to make an affordable version of what has been the best-selling car in the world on several occasions, enabling more accessibility.
The differences from an interior standpoint are noticeable, as there is significantly less storage, a lack of A/C seats, and no glass roof. However, the car is still a great option and features a good powertrain, strong range ratings of 321 miles for the RWD and 294 miles for the AWD, and a great ride quality.
Tesla Model Y Standard Full Review: Is it worth the lower price?
Other shortcomings are the lack of acoustic-lined windows, which are featured in the Premium trims to help with excess cabin noise. In our testing of the Model Y Standard back in late 2025, this was perhaps the most noticeable difference between it and the Premium trim. The stereo was also a huge difference:
This now includes the Model Y RWD and AWD, the two trims that were formerly know as “Standard”
You can see what the big differences are between the RWD/AWD and the Premium below:
https://t.co/ptLnm95KjX https://t.co/vaMUZz30UC pic.twitter.com/scuRNErXoC
— TESLARATI (@Teslarati) June 5, 2026
The RWD and AWD trims of the Model Y are still a great vehicle at an affordable price, and you can experience them for yourself at your local Tesla showroom. Test drives are always available, and it’s a great way to experience an EV for yourself, especially if you have no knowledge about them.
Tesla has its answer to grow its automotive sales over the next few years, TD Cowen analyst Itay Michaeli says, but it just has to bring it to the U.S.
On Thursday, Michaeli reiterated his $490 price target and the ‘Buy’ rating he already held on Tesla stock (NASDAQ: TSLA). However, its automotive division has struggled to show sequential growth over the past few years, mostly due to its focus on AI and Full Self-Driving. Tesla already axed two of its lower-volume vehicles with the Model S and Model X earlier this year.
However, Tesla does not need to engineer an entire new vehicle to trigger an upward tick in sales; it just has to bring it from China to the U.S., Michaeli said.
He is talking about the Model Y L, a slightly larger version of the all-electric crossover that is already available in China. U.S. customers have been pleading with CEO Elon Musk to bring it to the country since its launch in Asia last year, but he’s not convinced of it because of the advent of self-driving and its importance in this particular market.
The problem is that Tesla owners have been requesting something larger that could fit a typical American family. The Model Y L is slightly larger than the standard Model Y, but some are concerned that it could still be too small to fit what most people might need.
Instead, they have asked for a full-size SUV from Tesla.
Tesla gives big hint that it will build Cyber SUV, smaller Cybertruck
Nevertheless, the Model Y L still presents a great opportunity for Tesla in the U.S., and Michaeli says that there is an additional sales opportunity of about 100,000 units, with demand potential falling somewhere between 60,000 and 135,000 units.
TD Cowen’s note to investors also analyzed that Tesla’s growth could come from a stock perspective as well, positively impacting the stock price, as it has been widely reliant on vehicle sales, even though Tesla has truly phased itself away from that being an important metric.
Tesla stands to gain greatly from the introduction of the Model Y L in the U.S., but only if Elon Musk sees it as a viable fit for the market. Families may need to see Tesla bring something larger to the U.S., or they might be forced to buy from another automaker that offers something that fits is needs for more interior space to haul around the kids.
Tesla Hardware 3 owners are set to get a new Full Self-Driving version this month as the company plans to release what it is referring to as v14 Lite.
The rollout is not yet confirmed for June, but Tesla executives have stated on several occasions that this more refined FSD iteration will work with their cars and increase its capabilities.
This comes after Tesla admitted during its last Earnings Call that these Hardware 3 vehicles would not be able to achieve Full Self-Driving, something that they did not know when they bought these cars. We regularly receive messages from Hardware 3 owners asking when v14 Lite will come out, what they should expect, and whether it is worth it to upgrade the self-driving computer or buy a new car altogether.
Following future rollout of FSD V14 Lite for HW3 vehicles in the US, we plan on expanding V14 Lite to additional international markets.
This update ensures that HW3 vehicle owners will continue to benefit from ongoing software updates.
Since international rollout is subject to…
— Tesla (@Tesla) April 29, 2026
It is hard not to feel for them; Tesla CEO Elon Musk said at the company’s 2019 Autonomy Day that all vehicles produced at the time, including Hardware 3 cars, had “all the hardware necessary, compute and otherwise, for Full Self-Driving.”
Musk also said in March of that year that, “Anyone who purchased Full Self-Driving will get FSD computer upgrade for free.”
Anyone who purchased full self-driving will get FSD computer upgrade for free. This is the only change between Autopilot HW2.5 & HW3. Going forward “HW3” will just be called FSD Computer, which is accurate. No change to vehicle sensors or wire harness needed. This is v important. https://t.co/lICMpT7xnX
— Elon Musk (@elonmusk) March 29, 2019
However, during the Q1 2026 Earnings Call, Musk admitted that Hardware 3 vehicles would not be capable of FSD, as “It has only 1/8th the memory bandwidth of Hardware 4, and memory bandwidth is one of the key elements needed for unsupervised FSD.”
Tesla has made some effort to remedy these Hardware 3 owners by offering:
- Discounted trade-ins toward AI4 cars
- Hardware retrofits, which would replace the self-driving computer and upgrade all cameras
- Full Self-Driving v14 Lite
The issue is that many of these owners were led to believe their cars would be capable of unsupervised self-driving. Now, they’re left scrambling for options, and while there are several, they will all require more money out of their pockets.
Expectations for Tesla v14 Lite for Hardware 3 Owners
The big differences between the AI4 v14 and v14 Lite for Hardware 3 owners will stem primarily from hardware constraints. Tesla developed v14 Lite with an optimized frame of mind; the v14 neural nets are toned down to run on an HW3 computer.
Tesla v14 will use the same behavior, but its limits will be hardware-related, especially given that the cameras on HW3 vehicles are lower-resolution.
Tesla reveals its plans for Hardware 3 owners who are eager for updates
This will result in potentially more edge cases due to the lower quality perception and less long-range detection, but reaction time and overall confidence should be more refined.
There should also be a handful of additional features that are available on AI4 cars, such as:
- Starting Full Self-Driving from Park
- Auto Shift
- Streaks
- Speed Profiles
- Improved Dynamics, like Pulling Over for Emergency Vehicles
Tesla plans to release v14 Lite this month, but we are all familiar with how the company can be with timelines. Additionally, if v14 Lite has not proven to be ready for a wide release, Tesla will slam the brakes on the rollout.
We would anticipate that Tesla is testing v14 Lite internally, and likely has been for several months.
Tesla upgrades Model Y’s affordable trims with new interior features
Tesla has its answer to auto growth, it just has to bring it to the U.S.: analyst
