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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 shocked with its quarterly delivery report yesterday by reporting it delivered 480,126 vehicles in the second quarter of 2026, a 25 percent year-over-year jump that crushed Wall Street estimates of roughly 400,000–408,000 units. Production reached 451,758, with Model 3 and Model Y accounting for the vast majority.
The result ended two years of annual delivery declines and drew down inventory, signaling demand that outpaced earlier production.
Tesla bears had long warned that the expiration of the U.S. federal EV tax credit would hammer demand. Without the $7,500 incentive, they argued, American buyers would balk at higher effective prices, leading to a sharp slowdown.
Will Tesla thrive without the EV tax credit? Five reasons why they might
That narrative has not played out as predicted. While U.S. EV sales faced broader headwinds, Tesla’s global numbers held firm, underscoring the company’s ability to offset domestic pressure through other levers.
There are several plausible factors that explain Tesla’s strength during this quarter. Let’s take a look at them:
Rising Gas Prices
Rising gas prices provided a powerful tailwind, especially in the U.S.
Geopolitical tensions tied to the Iran conflict pushed fuel costs higher earlier in the year, amplifying the lifetime savings of electric vehicles. Even as oil prices later moderated, the psychological and financial impact lingered, encouraging fleet operators and private buyers to accelerate EV purchases. European sales rebounded sharply, helping drive the quarter’s outperformance.
Full Self-Driving Adoption
Advances in Full Self-Driving (FSD) supervised software also appear to have boosted appeal. Tesla expanded FSD availability in select European markets and continued refining the system.
No complaints from me because I finally got to enjoy this drive on FSD; I usually like to manually drive down this mountain https://t.co/RBFniRPSR0 pic.twitter.com/XQ5sOpN1Yg
— TESLARATI (@Teslarati) June 26, 2026
For tech-oriented buyers, the promise of future autonomy and enhanced driver-assistance features adds perceived value beyond the car itself. This differentiation helps Tesla stand out in a crowded market where competitors focus primarily on hardware and basic range.
Pricing Strategy, Affordable Configurations
Tesla’s offerings and its pricing strategy during Q2 further stimulated demand. Tesla introduced lower-cost versions of the Model 3 and Model Y, widening accessibility without sacrificing core margins.
These moves countered affordability concerns and attracted buyers who had been waiting on the sidelines. Combined with attractive financing and leasing options, the pricing strategy converted interest into actual orders more effectively than many analysts expected.
Broad European Recovery
Supported by government incentives, corporate fleet electrification, and easing political headwinds around CEO Elon Musk, Tesla was supplied additional momentum through stronger registration numbers throughout Europe.
Strong exports from the Shanghai Gigafactory and a production ramp at Giga Berlin ensured supply met this resurgent demand. Corporate buyers, in particular, accelerated transitions to EVs to meet sustainability targets, providing a steady volume base.
These elements created a virtuous cycle that delivered the strong deliveries report. While bears correctly flagged the loss of the U.S. tax credit as a risk, Tesla’s diversified playbook demonstrated that it could remain resilient against those headwinds. The Q2 beat suggests the company remains adept at navigating shifting market conditions, even as competition intensifies.
A Tesla Semi was involved in a fatal collision on U.S. Highway 50 in Dayton, Nevada, on Sunday, June 28, 2026, marking the first known fatal crash involving the electric Class 8 truck. The incident occurred around 7:20 a.m. at the intersection with Traditions Parkway, approximately 40 miles east of Reno and close to Tesla’s Gigafactory Nevada.
According to the Lyon County Sheriff’s Office and the Nevada State Police Highway Patrol, a semi-truck struck two passenger vehicles stopped at a traffic signal. The truck hit the vehicles from behind. Two people were pronounced dead at the scene, and a third person suffered life-threatening injuries and was flown to a hospital, Forbes reported.
Preliminary statements gathered at the scene by the Lyon County Sheriff’s Office suggested the truck driver may have fallen asleep at the wheel. However, the Nevada Highway Patrol, which is leading the investigation, stated that the official cause has not yet been determined.
Additional information is expected to be released early the following week. The truck was seized for evidence as part of the ongoing probe.
Responders at the scene included deputies from the Lyon County Sheriff’s Office, personnel from the Nevada Highway Patrol, Central Lyon County Fire Department, and the Nevada Department of Transportation. The crash led to the temporary closure of U.S. 50 in both directions.
The Tesla Semi is Tesla’s battery-electric heavy-duty truck, produced at the nearby Gigafactory in Nevada. Authorities initially described the vehicle as a semi-truck; its make was subsequently confirmed through reporting and scene identification; an interesting bit of information here, as the Semi is not yet available publicly and many do not know that Tesla builds electric trucks.
The investigation remains active, with no further official details on contributing factors or vehicle systems released as of early July 2026.
This incident highlights ongoing scrutiny of commercial vehicle safety on Nevada highways, particularly involving fatigue. Law enforcement continues to gather evidence and witness statements.
Tesla has expanded its Robotaxi program to Miami, Florida, marking the third state the autonomous ride-hailing platform has made its way to since launching last Summer.
Tesla announced today that the Robotaxi suite would now officially launch rides in a geofence in Miami:
🚨 Tesla’s “Long Weekend” continues with a HUGE announcement regarding Robotaxi!
It’s now in Miami!
Miami joins Austin, Dallas, Houston, and the Bay Area! https://t.co/ujjYjJT3Im pic.twitter.com/yPe1ZdSQIE
— TESLARATI (@Teslarati) July 3, 2026
The first geofence in Miami covers approximately 10 to 14 square miles. The area appears to be focused on western and central Miami, including Miami International Airport (MIA). It also includes popular routes like SR 826 (Palmetto Expressway), US 41 (Tamiami Trail), and connectors such as SR 968, 953, 959, and 972.
This is Tesla’s initial Miami launch zone, smaller and more targeted than some competitors’ areas (for example, Waymo’s initial rollout was broader in eastern neighborhoods). It prioritizes high-traffic, airport-linked routes before wider expansion.
The expansion is a huge signal for Tesla that it is now operating in Florida, a heavy-traffic state with many tourist areas, including Fort Lauderdale, Palm Beach, and the Boynton area, all of which are coastal and will attract perhaps millions of tourists in any given year.
¿Qué lo que Miami?
Robotaxi now available in Miami pic.twitter.com/P1m283seZU
— Tesla Robotaxi (@robotaxi) July 3, 2026
The Tesla Robotaxi network launched last year on June 22, in Austin, Texas, beginning limited commercial operations in that city. It expanded shortly thereafter into the San Francisco Bay Area of California in late July 2025, marking entry into a second state with service covering key areas such as San Francisco, San Jose, and Berkeley.
Full commercial service was achieved in Austin by November 18, 2025, strengthening its presence within Texas before further growth.
In 2026, the network continued expanding across Texas with the addition of Dallas and Houston on April 18, significantly broadening its footprint in the state. This new launch into Miami marks Tesla entering a new state and bringing active locations to include Austin, Dallas, Houston, San Antonio in Texas, and the Bay Area in California.
These sequential expansions have steadily increased the network’s reach across major metropolitan areas in Texas, California, and Florida, focusing on scaling operations city by city and state by state since the initial Austin debut.
Tesla’s strong Q2 deliveries: Four key drivers behind the surprise
Tesla Semi involved in first known fatal crash in Nevada
