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.
Tesla’s long-promised Cybercab is finally available for personal purchase, at least for a select few in the Austin area. But it’s far from a straightforward ownership experience.
The $29,990 price tag comes with a stack of restrictions that redefine what “owning” the vehicle actually means. The two-seat, steering-wheel-free Robotaxi, previously limited to Tesla’s own fleet, now carries contractual terms that limit where it can go, how it can be used, and whether it can even move without an active paid subscription.
Opening Night of Orders
Late on November 13, Tesla announced that select customers were being invited to order a Cybercab for personal use.
Tesla Cybercab goes on sale for $29,990, slated for December deliveries
The estimated purchase price is $29,990 before taxes, paired with a non-refundable $1,000 deposit and an estimated December 2026 delivery in Austin, Texas. The first month of the required :Autonomy Subscription,” priced at $299 per month is included.
After that, the vehicle needs an active subscription to operate at all. The announcement confirmed that customer sales had begun, albeit on an invite-only basis rather than a public order page.
The Fine Print for Buyers
BREAKING: Tesla’s Cybercab Autonomy Subscription terms are now live. A paid monthly subscription is required.
1/12 Tesla: “Your Cybercab will not operate without an active Autonomy Subscription. 🧵 https://t.co/umVk6DJE2x— Spencer (@scotsrule08) November 13, 2026
For those invited to order, the agreements (Cybercab Order Agreement, Terms of Use, and Autonomy Subscription Agreement) impose significant constraints. Major points include:
- A mandatory Autonomy Subscription (currently listed at $299 per month on the order screen, first month included) is required; without it, the Cybercab will not operate.
- Personal, non-commercial use only; ride-hailing, Robotaxi network participation, delivery, or rental requires separate written authorization or product enablement from Tesla.
- Operation restricted to Tesla-enabled Robotaxi geofences and supported service areas, which the company can expand, shrink, or alter; the vehicle may be technologically prevented from operating outside them.
- No unauthorized modifications (including wraps, window tint, or wheel changes) without Tesla or an authorized provider.
- Restricted resale and transfer: written permission required, with contractual damages of at least $50,000 (or full transaction value if higher) for unauthorized sales; Tesla also reserves repurchase rights at a company-determined fair market value, with the owner covering return costs.
- Safety or improper-use “strikeouts” (three or more) can trigger a one-week suspension of autonomous features without prorated refund.
- Owners remain responsible for insurance, registration, charging, parking, and general cleaning; the subscription covers certain maintenance items such as tires, windshields, filters, and camera cleaning, plus limited towing.
- Manual controls on the touchscreen allow only short-distance movement up to about 2 mph and require a valid driver’s license; they are not for public-road driving.
Why These Terms Might Exist
Tesla’s approach prioritizes control over a vehicle designed without traditional human controls and intended primarily as transport-as-a-service, something that Musk has hinted toward for some time now. Restricting commercial use and modifications could be as much of a software integrity, safety, and data collection effort as it is a safety effort.
Fleet consistency could also be in regulatory scrutiny early on in the Cybercab’s days of public operation.
The subscription model generates ongoing revenue beyond the low vehicle price and ensures the car remains connected and updatable, something that will keep the Cybercab as safe as possible as new updates roll out.
Buyback and resale limits reduce the risk of vehicles circulating outside Tesla’s operational and service ecosystem.
It apperas that personal ownership is secondary to the broader Robotaxi network strategy, as Musk has previously stated that the vast majority of Cybercabs would remain Tesla-owned.
Pickup Locations and Musk’s Pricing View
Initial deliveries are estimated for Austin, but personal vehicles are able to operate in any of Tesla’s Robotaxi geofences:
It’ll work unsupervised inside all the same geo locations as @robotaxi, just serving the owners’ needs.
— Ashok Elluswamy (@aelluswamy) November 14, 2026
Those who have been invited to order can also have their personal Cybercab delivered to numerous locations in Texas, including:
- Austin
- Dallas
- Houston
- San Antonio
- Fort Worth
Interesting that you can choose a delivery city https://t.co/SknDz9rFzo
— Whole Mars Catalog (@wholemars) November 14, 2026
As far as the monthly “Autonomy Subscription,” it appears Musk already wants it to be low. He acknowledged last night on X that the subscription price is too high. Along with detailing that the Cybercab will be available nationwide as regulatory approval is received, Musk said the monthly fee should match the cost of FSD and Premium Connectivity, which is about $115 per month.
The launch marks a milestone for unsupervised personal autonomous vehicles, but the fine print makes clear that buyers are purchasing a highly constrained asset whose usefulness is tightly bound to Tesla’s software, service network, and geographic approvals.
Tesla has officially put the Cybercab up for sale, revealing a bargain price and a $299 per month “Autonomy Subscription” that could hit customer hands as soon as December.
The offer requires a $299 monthly Autonomy Subscription, with the first month included in the purchase price, along with a $1,000 non-refundable order deposit. Tesla’s ordering interface shows deliveries targeted for Austin, Texas.
Tesla says that the Cybercab is making transportation more efficient, affordable and accessible than ever before, and that buyers can order their own Cybercab for personal use.
🚨🚨🚨 BREAKING: Tesla Cybercab is officially on sale for $29,990 with a $299/mo “Autonomy Subscription”
Delivery slotted for December! HUGE!
— TESLARATI (@Teslarati) November 13, 2026
The Cybercab is Tesla’s dedicated robotaxi, a gold-finished, two-passenger vehicle without a steering wheel or pedals, designed from the outset for unsupervised autonomous operation. It has been in limited Robotaxi service in Austin since September 2026, operating alongside Tesla’s larger fleet of Model Y vehicles.
Production takes place at Gigafactory Texas, which launched earlier this year. Tesla has stated for some time that it planned to put Cybercabs on sale by the end of the year, and it looks like they will come through on that promise if everything goes according to plan.
The Autonomy Subscription is mandatory for the vehicle to operate because it is void of a steering wheel and pedals. Tesla notes that the subscription and regular vehicle maintenance are required, indicating that personal owners will depend on the company’s software and service infrastructure rather than traditional ownership models.
One month of the subscription is included with purchase and subsequent months are billed separately until canceled.
This limited personal-sales opening marks a shift from Tesla’s earlier emphasis on fleet and transport-as-a-service operations. During the Q3 2026 Earnings Call, executives indicated that the vast majority of Cybercabs would remain Tesla-owned and used for rideshare service, while still aiming to place some vehicles with customers by year-end.
Elon Musk has previously targeted a price below $30,000, which was a huge point of emphasis for the Cybercab being the central point of Tesla’s “transportation-as-a-service” model.
Availability remains restricted to invited customers rather than a public order page, and the initial deliveries are expected only in the Austin area where unsupervised Robotaxi operations are already active. Buyers will need to accept the geographic and operational constraints of current autonomous deployment, as the vehicle cannot be driven manually outside supported zones.
The move gives a small number of early buyers the chance to own Tesla’s dedicated autonomous vehicle at the long-discussed sub-$30,000 price point, while the bulk of production continues to support the company’s expanding Robotaxi network.
UPDATE: The FAA has granted the license for Starship Flight 15.
Starship Flight 15 License has been granted by the FAA!
Let’s go! https://t.co/DugsgjvYAe
— TESLARATI (@Teslarati) November 13, 2026
SpaceX is set to attempt its 15th test flight of Starship this evening from Starbase, Texas.
SpaceX is targeting Starship Flight 15 for a launch as soon as today, Friday, November 13, pending an FAA Flight License, during a 75-minute window that opens at 4:45 p.m. CT (5:45 p.m. ET) from Orbital Launch Pad 2 at Starbase, Texas. The flight remains pending final regulatory approval.
WATCH Starship Flight 15 here:
https://t.co/C6GnCHyF8p
— TESLARATI (@Teslarati) November 13, 2026
The mission, using Booster 22 and Ship 42, aims to achieve the first full recovery of an orbital launch system. Primary objectives include a tower catch of the Super Heavy booster roughly six and a half minutes after liftoff and the first-ever tower catch of a Starship upper stage after more than 22 hours in space.
SpaceX will perform Starship double catch attempt with Flight 15
Between those catches, Ship 42 is planned to enter a low Earth orbit of about 275 km, complete roughly 14 orbits, and deploy 26 next-generation Starlink V3 satellites (Starlink Group 31-2). Three of those satellites carry cameras to inspect the ship’s heat shield in orbit and help controllers decide whether the vehicle is healthy enough for a return to the tower.
Contingency ocean splashdown options exist if either stage is not cleared for catch.
To watch the attempt, check the link to the broadcast in both X posts in this article. The live webcast is scheduled to begin about 30 minutes before liftoff and is planned to continue through the ship catch the next day, with the possibility of extended onboard views during the orbital coast via Starlink.
Because the schedule is dynamic, check back here or on our social media channels for the latest updates on window timing and regulatory status. A successful dual catch would mark a major milestone toward making Starship a rapidly reusable rocket capable of frequent flights.
WATCH Starship Flight 15 here:
https://t.co/C6GnCHyF8p
— TESLARATI (@Teslarati) November 13, 2026
Tesla Cybercab arrives with steep ownership fine print
Tesla Cybercab goes on sale for $29,990, slated for December deliveries
