

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.
Elon Musk
Tesla called ‘biggest meme stock we’ve ever seen’ by Yale associate dean

Tesla (NASDAQ: TSLA) is being called “the biggest meme stock we’ve ever seen” by Yale School of Management Senior Associate Dean Jeff Sonnenfeld, who made the comments in a recent interview with CNBC.
Sonnenfeld’s comments echo those of many of the company’s skeptics, who argue that its price-to-earnings ratio is far too high when compared to other companies also in the tech industry. Tesla is often compared to companies like Apple, Nvidia, and Microsoft when these types of discussions come up.
Fundamentally, yes, Tesla does trade at a P/E level that is significantly above that of any comparable company.
However, it is worth mentioning that Tesla is not traded like a typical company, either.
Here’s what Sonnenfeld said regarding Tesla:
“This is the biggest meme stock we’ve ever seen. Even at its peak, Amazon was nowhere near this level. The PE on this, well above 200, is just crazy. When you’ve got stocks like Nvidia, the price-earnings ratio is around 25 or 30, and Apple is maybe 35 or 36, Microsoft around the same. I mean, this is way out of line to be at a 220 PE. It’s crazy, and they’ve, I think, put a little too much emphasis on the magic wand of Musk.”
Many analysts have admitted in the past that they believe Tesla is an untraditional stock in the sense that many analysts trade it based on narrative and not fundamentals. Ryan Brinkman of J.P. Morgan once said:
“Tesla shares continue to strike us as having become completely divorced from the fundamentals.”
Dan Nathan, another notorious skeptic of Tesla shares, recently turned bullish on the stock because of “technicals and sentiment.” He said just last week:
“I think from a trading perspective, it looks very interesting.”
Nathan said Tesla shares show signs of strength moving forward, including holding its 200-day moving average and holding against current resistance levels.
Sonnenfeld’s synopsis of Tesla shares points out that there might be “a little too much emphasis on the magic wand of Musk.”
Elon Musk just bought $1 billion in Tesla stock, his biggest purchase ever
This could refer to different things: perhaps his recent $1 billion stock buy, which sent the stock skyrocketing, or the fact that many Tesla investors are fans and owners who do not buy and sell on numbers, but rather on news that Musk might report himself.
Tesla is trading around $423.76 at the time of publication, as of 3:25 p.m. on the East Coast.
News
Tesla makes big change to Full Self-Driving doghouse that drivers will like
Now, it is changing the timeframe of which strikes will be removed, cutting it in half. The strikes will be removed every 3.5 days, as long as no strikes are received during the time period.

Tesla is making a big change to its Full Self-Driving doghouse that drivers will like.
The doghouse is a hypothetical term used to describe the penalty period that Tesla applies to drivers who receive too many infractions related to distracted driving.
Previously, Tesla implemented a seven-day ban on the use of Full Self-Driving for those who received five strikes in a vehicle equipped with a cabin camera and three strikes for those without a cabin camera.
It also forgave one strike per week of Full Self-Driving use, provided the driver did not receive any additional strikes during the seven-day period.
Now, it is changing the timeframe of which strikes will be removed, cutting it in half. The strikes will be removed every 3.5 days, as long as no strikes are received during the time period.
The change was found by Not a Tesla App, which noticed the adjustment in the Owner’s Manual for the 2025.32 Software Update.
The system undoubtedly helps improve safety as it helps keep drivers honest. However, there are definitely workarounds, which people are using and promoting for monetary gain, and you can find them on basically any online marketplace, including TikTok shop and Amazon:
🚨 Seeing more and more devices like this land on various online marketplaces including TikTok shop and Amazon
These devices are NOT to be used when operating Tesla Full Self-Driving and I’d love to see Tesla take action here.
These “creators” looking to make a quick buck are… pic.twitter.com/VnY25k2mPL
— TESLARATI (@Teslarati) September 17, 2025
People are marketing the product as an FSD cheat device, which the cabin-facing camera will not be able to detect, allowing you to watch something on a phone or look through the windshield at the road.
The safeguards implemented by Tesla are designed to protect drivers from distractions and also protect the company itself from liability. People are still using Full Self-Driving as if it were a fully autonomous product, and it is not.
Tesla even says that the driver must pay attention and be ready to take over in any scenario:
“Yes. Autopilot is a driver assistance system that is intended to be used only with a fully attentive driver. It does not turn a Tesla into a fully autonomous vehicle.
Before enabling Autopilot, you must agree to “keep your hands on the steering wheel at all times” and to always “maintain control and responsibility for your vehicle.” Once engaged, Autopilot will also deliver an escalating series of visual and audio warnings, reminding you to place your hands on the wheel if insufficient torque is applied or your vehicle otherwise detects you may not be attentive enough to the road ahead. If you repeatedly ignore these warnings, you will be locked out from using Autopilot during that trip.
You can override any of Autopilot’s features at any time by steering or applying the accelerator at any time.”
It is good that Tesla is rewarding those who learn from their mistakes with this shorter timeframe to lose the strikes. It won’t be needed forever, though, as eventually, the company will solve autonomy. The question is: when?
Elon Musk
Elon Musk teases the capabilities of the Tesla Roadster once again

Elon Musk has once again teased the capabilities of the Tesla Roadster, fueling the anticipation that many have for the vehicle, despite it still having no public production or delivery date.
The Roadster is among the most anticipated vehicles in the automotive sector currently, and as Tesla has teased its capabilities, from a lightning-fast 1.1-second 0-60 MPH acceleration to potential hovering with cold-gas thrusters, people are eager to see it.
Although the design seemed to be finalized, there was still more work to be done. Earlier this year, as Tesla was showcasing some of the Roadster’s capabilities to Musk, he stated that it was capable of even more.
This pushed back its production date even further, much to the chagrin of those who have been waiting years for it.
Musk continues to tease us all, and as we sit here waiting hopelessly for it to be revealed, he said today that it is “something special beyond a car.”
The new Roadster is something special beyond a car
— Elon Musk (@elonmusk) September 17, 2025
Musk’s words were in response to a video posted by Tesla China, showing the Roadster in a new promotional video created by a fan.
The Roadster was planned to be released in 2020, but here we are in 2025, and there is still no sign of the vehicle entering production. However, Tesla did say earlier this year that it would host a demo event for the Roadster, where the company would showcase its capabilities.
Lars Moravy said earlier this year:
“Roadster is definitely in development. We did talk about it last Sunday night. We are gearing up for a super cool demo. It’s going to be mind-blowing; We showed Elon some cool demos last week of the tech we’ve been working on, and he got a little excited.”
Tesla exec gives big update on Roadster, confirming recent rumor
The delays have been attributed to “radically increased design goals” for the vehicle, which have, without a doubt, improved its capabilities, but at the same time, we just want to know if it’s ever going to come.
Tesla can always make it “better,” but at what point do you say, “Okay, it’s time to show this thing off.” They could always build another, even more capable supercar in the next ten years.
-
Elon Musk2 weeks ago
Tesla’s next-gen Optimus prototype with Grok revealed
-
News2 weeks ago
Tesla launches new Supercharger program that business owners will love
-
Elon Musk2 weeks ago
Tesla Board takes firm stance on Elon Musk’s political involvement in pay package proxy
-
News2 weeks ago
Tesla deploys Unsupervised FSD in Europe for the first time—with a twist
-
News2 weeks ago
Tesla explains why Robotaxis now have safety monitors in the driver’s seat
-
News2 weeks ago
Tesla is already giving Robotaxi privileges hours after opening public app
-
Elon Musk2 weeks ago
Elon Musk says Tesla will take Safety Drivers out of Robotaxi: here’s when
-
Elon Musk2 weeks ago
Elon Musk is setting high expectations for Tesla AI5 and AI6 chips