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University of Michigan uses recycled Kevlar fiber to solve lithium-sulfur battery life cycle issues

(Credit: University of Michigan)

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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.

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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.

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Joey has been a journalist covering electric mobility at TESLARATI since August 2019. In his spare time, Joey is playing golf, watching MMA, or cheering on any of his favorite sports teams, including the Baltimore Ravens and Orioles, Miami Heat, Washington Capitals, and Penn State Nittany Lions. You can get in touch with joey at joey@teslarati.com. He is also on X @KlenderJoey. If you're looking for great Tesla accessories, check out shop.teslarati.com

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Elon Musk

Elon Musk sends stern warning to Tesla vandals, doubters

Elon Musk sent another warning to vandals that have attacked Tesla for political reasons.

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NORAD and USNORTHCOM Public Affairs, Public domain, via Wikimedia Commons

Elon Musk has sent a stern warning to Tesla vandals, doubters, and attackers, who have subjected the company and its owners to political violence through arson and other modes of retaliation.

Over the past few months, Tesla showrooms and vehicles have been hit with numerous attacks from those who have opposed Musk and his political involvement with the Trump Administration. Although Musk has stepped back from his role within government significantly since the start of May, the company is still looked at as a political target.

While the White House has put a clear-cut line on the acts, calling them domestic terrorism and holding those responsible for the damage they have done, there are still numerous and daily instances of keying cars or worse.

Yesterday, Musk continued to send stern warnings to those who oppose Tesla and choose to handle their distaste for the company with violence and vandalism. In a Bloomberg interview at the Qatar Economic Forum, Musk was asked if he took what has happened to Tesla “over the past few months personally.”

Musk replied simply but sternly: “Yes.”

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He went on to say that not only will those who vandalized the company and its products owned by consumers be held to the fullest extent of the law, but also those who fund it.

Musk also said during a CNBC interview yesterday that very few people buy a company’s products because of the CEO’s political beliefs, and many people do not even know where those CEOs stand on various social issues.

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Although Musk has gone out of his way to be transparent about his beliefs, he has a valid point. He obviously felt that, because of his influence, he held a duty to uphold American values and protect what he felt was an attack on free speech and human rights.

Disagreeing with Musk and his political stances is totally reasonable, but damaging products that consumers bought from his companies is not impacting him directly. Instead, it is making consumers’ lives more difficult.

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Tesla Model 3 gets perfect 5-star Euro NCAP safety rating

Tesla prides itself on producing some of the safest vehicles on the road today.

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Credit: Tesla Singapore/X

Tesla prides itself on producing some of the safest vehicles on the road today. Based on recent findings from the Euro NCAP, the 2025 Model 3 sedan continues this tradition, with the vehicle earning a 5-star overall safety rating from the agency.

Standout Safety Features

As could be seen on the Euro NCAP’s official website, the 2025 Model 3 achieved an overall score of 90% for Adult Occupants, 93% for Child Occupants, 89% for Vulnerable Road Users, and 87% for Safety Assist. This rating, as per the Euro NCAP, applies to the Model 3 Rear Wheel Drive, Long Range Rear Wheel Drive, Long Range All Wheel Drive, and Performance All Wheel Drive.

The Euro NCAP highlighted a number of the Model 3’s safety features, such as its Active Hood, which automatically lifts during collisions to mitigate injury risks to vulnerable road users, and Automatic Emergency Braking System, which now detects motorcycles through an upgraded algorithm. The Euro NCAP also mentioned the Model 3’s feature that prevents initial door opening if someone is approaching the vehicle’s blind spot.

Standout Safety Features

In a post on its official Tesla Europe & Middle East account, Tesla noted that the company is also introducing new features that make the Model 3 even safer than it is today. These include functions like head-on collision avoidance and crossing traffic AEB, as well as Child Left Alone Detection, among other safety features.

“We also introduced new features to improve Safety Assist functionality even further – like head-on collision avoidance & crossing traffic AEB – to detect & respond to potential hazards faster, helping avoid accidents in the first place. 

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“Lastly, we released Child Left Alone Detection – if an unattended child is detected, the vehicle will turn on HVAC & alert caregivers via phone app & the vehicle itself (flashing lights/audible alert). Because we’re using novel in-cabin radar sensing, your Tesla is able to distinguish between adult vs child – reduced annoyance to adults, yet critical safety feature for kids,” Tesla wrote in its post on X.

Below is the Euro NCAP’s safety report on the 2025 Tesla Model 3 sedan.

Euroncap 2025 Tesla Model 3 Datasheet by Simon Alvarez on Scribd

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Elon Musk

USDOT Secretary visits Tesla Giga Texas, hints at national autonomous vehicle standards

The Transportation Secretary also toured the factory’s production lines and spoke with CEO Elon Musk.

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Credit: Elon Musk/X

United States Department of Transportation (USDOT) Secretary Sean Duffy recently visited Tesla’s Gigafactory Texas complex, where he toured the factory’s production lines and spoke with CEO Elon Musk. In a video posted following his Giga Texas visit, Duffy noted that he believes there should be a national standard for autonomous vehicles in the United States.

Duffy’s Giga Texas Visit

As could be seen in videos of his Giga Texas visit, the Transportation Secretary seemed to appreciate the work Tesla has been doing to put the United States in the forefront of innovation. “Tesla is one of the many companies helping our country reach new heights. USDOT will be right there all the way to make sure Americans stay safe,” Duffy wrote in a post on X. 

He also praised Tesla for its autonomous vehicle program, highlighting that “We need American companies to keep innovating so we can outcompete the rest of the world.”

National Standard

While speaking with Tesla CEO Elon Musk, the Transportation Secretary stated that other autonomous ride-hailing companies have been lobbying for a national standard for self-driving cars. Musk shared the sentiment, stating that “It’d be wonderful for the United States to have a national set of rules for autonomous driving as opposed to 50 independent sets of rules on a state-by-state rules basis.”

Duffy agreed with the CEO’s point, stating that, “You can’t have 50 different rules for 50 different states. You need one standard.” He also noted that the Transportation Department has asked autonomous vehicle companies to submit data. By doing so, the USDOT could develop a standard for the entire United States, allowing self-driving cars to operate in a manner that is natural and safe.

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