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Supercapacitor breakthrough suggests EVs could charge in seconds but with a trade-off
Supercapacitors may be providing an alternative to electric-car batteries sooner than expected, according to a new research study. Currently, supercapacitors can charge and discharge rapidly over very large numbers of cycles, but their poor energy density per kilogram —- at just one twentieth of existing battery technology — means that they can’t compete with batteries in most applications.
That’s about to change, say researchers from the University of Surrey and University of Bristol in conjunction with Augmented Optics. They have announced a breakthrough in supercapacitors, which are said to be between 1000 and 10,000 times more powerful than equivalent lithium-ion batteries and considerably quicker to recharge. However, they lack the storage capacity found in traditional automotive-grade lithium-ion batteries used in today’s electric cars. But Jim Heathcote, chief executive of Augmented Optics Ltd and Supercapacitor Materials Ltd, says consumers would likely still be happy with the trade off by having faster charging times. “A lot of people would be more happy with a half the range of a 300-mile, lithium ion-batteried EV, but a fast charging time”. If their research can be translated into the consumer market, EVs could re-charge in a time quicker than filling a vehicle with a tank of gasoline.
Tesla CEO Elon Musk has remarked in the past about the use of supercapcitors in electric vehicles, “If I were to make a prediction, I’d think there’s a good chance that it is not batteries, but super-capacitors.” The recent research could be a first sign that Musk’s prediction from five years ago could one day come to fruition.
Why a combination of batteries and supercapacitors is essential to a sustainable future
In the next few decades, fossil-fueled cars and home-heating systems will need to switch to electric power to avert catastrophic climate change. Electricity has tremendous benefits but also one significant drawback: it’s relatively difficult to store in a hurry. Batteries can hold large amounts of energy, but they take hours to charge. Capacitors are a solution to this dilemma, as they charge nearly instantaneously.
.@plugshare, assuming vast charging network WOULD YOU RATHER have a $35k #EV with …. https://t.co/awp6Nz9oQC
— TESLARATI (@Teslarati) December 6, 2016
A supercapacitor solves the problem of storing a reasonable amount of energy for a relatively short period of time. Supercapacitors have been typically used as energy reservoirs to stabilize power supplies to electrical and electronic equipment. But supercapacitors can also be connected to batteries to regulate the power they supply. However, up until this point, they have only been able to store minuscule amounts of energy.
To truly have a feasible electric-powered lifestyle in which we can store and release large amounts of energy very quickly, we need efficiency in both batteries and supercapacitors. Supercapacitors help to solve the “energy versus power” conundrum. “Energy” is the capacity to do work. In physics, work is the act of exerting a force over a distance. While energy measures the total quantity of work done, it doesn’t say how fast you can get the work done. “Power” is the rate of producing or consuming energy. Supercapacitors can bridge that divide and solve the inherent trade-off between EV energy and power.
Dr. Brendan Howlin of the University of Surrey said: “There is a global search for new energy storage technology and this new ultra-capacity supercapacitor has the potential to open the door to unimaginably exciting developments.”
They hope to have a working prototype by spring 2017. “We are now actively seeking commercial partners in order to supply our polymers and offer assistance to build these ultra-high-energy density storage devices,” said Heathcote. In current form, the high energy density supercapacitors could make it possible to recharge mobile phones, laptops, or other mobile devices in just a few seconds.
A fleet of supercapacitor-equipped buses is already in use in China, although they do not achieve the range proposed by the Surrey research team.
Shout out to Chris Woodford for background info.
Tesla has updated its Robotaxi app so riders can pick which vehicle they want before they book. The latest in-app screens now show two options side by side: the two-seat Cybercab and the four-seat Model Y.
A screenshot circulating Thursday shows the change in practice. In Austin, a rider could choose a gold Cybercab for two people or a Model Y for four. Tesla’s updated description calls Cybercab “our first purpose-built autonomous vehicle,” designed for safety, accessibility, and comfort, and says the lineup is available only through the Robotaxi app.
Tesla has updated their Robotaxi page in the App Store. You’ll be able to select if you want a Cybercab or Model Y Robotaxi.
“Our Robotaxi vehicle lineup now includes Cybercab, our first purpose-built autonomous vehicle. Designed for safety, accessibility and comfort, Cybercab… pic.twitter.com/Jff4klilDr
— Sawyer Merritt (@SawyerMerritt) September 3, 2026
The distinction is more than cosmetic, and it’s important to note that Robotaxi refers to the platform, while Cybercab refers to a vehicle.
Model Y Robotaxis have carried the service since it opened in Austin in mid-2025 and later expanded to Dallas, Houston, and parts of Florida. Those vehicles are converted production SUVs that still have steering wheels and pedals.
Cybercab is different. It has no driver controls, butterfly doors, a low seat height meant to work with wheelchairs, extra trunk space for assistive devices, and braille on the handles. Tesla has registered dozens of the two-seaters with Texas regulators in the days leading up to its September 3 Austin event.
Giving riders a choice lets Tesla match the vehicle to the trip. Most rides involve one or two people, which is where Cybercab is meant to be cheaper and more efficient to operate. Groups of three or four, or anyone who needs more space, can still request a Model Y.
The same app handles booking, payment, cabin settings, and, on Cybercab, features such as phone-based door opening and in-cabin voice controls.
The update does not mean every city suddenly has both cars available. Cybercab support is listed for Austin first, and the purpose-built fleet is still small compared with the existing Model Y roster. Even so, the app change marks a shift from a single-vehicle pilot to a mixed fleet.
Riders can now choose between the compact, purpose-built robotaxi and the familiar SUV that launched the service.
Tesla Cybercab sightings are broadening far and wide, well outside of downtown Austin, Texas, with autonomy in focus as the company plans to launch the all-electric, two-seater this evening in the Lone Star State.
Tesla is set to launch Cybercab to a small group of people this evening in a dedicated event in Austin, Texas. Public details on the event are relatively slim.
However, Tesla’s focus on Cybercab falls well outside of the downtown Austin area and is expanding well across the United States as things continue to move quickly with the company’s autonomous efforts in 2026. Today, various images of Cybercab fleets in interesting locations have started to circulate.
The most notable is a fleet of at least 20 Cybercabs at Miami International Airport in Florida. Spotted last night, the fleet is expansive and is indicative of a looming release of Cybercabs once regulatory boxes are checked off.
Tesla has already been operating the Robotaxi platform in Miami for several months, but this Cybercab fleet at the airport could be joining the ride-hailing platform as approvals arrive:
20+ Cybercabs spotted near Miami international airport. pic.twitter.com/ORLsw8yFhf
— Sawyer Merritt (@SawyerMerritt) September 3, 2026
Another fleet of Cybercabs was spotted at the Devon, PA showroom just outside of Philadelphia. We have seen several Cybercab units testing around the Philadelphia Metro Area, which is interesting considering Tesla does not have any active Robotaxi geofence in Pennsylvania.
Cybercab at the Devon location in PA has multiplied over the weekend. Seeing a few more test vehicles in the lot 👀 pic.twitter.com/DhJT4P1EkU
— Billy (@billykyle) August 22, 2026
Philadelphia would be an ideal location to test ride-hailing due to its dense tourist population, large, sprawling city layout, and to compete with other ride-hailing companies that operate in the city.
Expansive fleets of Cybercabs will be popping up in and around major cities throughout the rest of the year, if we were betting on it. Tesla has made it obvious that the Cybercab rollout will be aggressive and fast-paced, but within reason. Tesla is still prioritizing safety, so these testing phases will likely go on for some period of time before more members of the public are able to snag a Cybercab for a personal chariot.
The Tesla Model Y L is arguably the most hyped trim of the all-electric crossover, other than the Performance configuration that comes with white-knuckle speed and sports car-level handling.
However, it is not all perfect. Tesla owners in China who took delivery of the Model Y L, denoted with an L to highlight its longer wheelbase, are experiencing what they are referring to as “collapsing” of the rear wheels, as suspension issues appear to be an issue with some of the builds.
🚨 Model Y L owners in China report rear suspension sag
• Six-seat long-wheelbase Y. Shanghai. On sale since August 2025
• Owners say the rear tire-to-arch gap shrinks after mileage or a full load. Some cases after about 9,000 km loaded. Others near 30,000 km
• Tesla service… pic.twitter.com/Lr6i5Tbi07— Joe Hansen (@joehansen) September 1, 2026
The gap between the wheel arch and tire has narrowed to the point that “not even a single finger” could fit, according to a report from Car News China. The failures are not tied to a specific mileage, as one owner said that after just 9,000 kilometers (5,600 miles), they noticed the suspension issue when their car was fully loaded.
Another one had the issue at 30,000 kilometers (18,640 miles) and noticed that the wheel gap shrank to two fingers, so not as drastic as the person who reported a similar issue at 9,000 km.
Tesla Model Y L is gaining momentum in China’s premium segment
Along with the visual recognition of the issue, others are saying the sagging is causing abnormal wear on the inside of the tires. Extra weight and instant torque already provide additional stress on the tires in electric vehicles during normal operation, so it is no surprise that this is another complaint.
There has been no recall issued by Tesla, and the company has not yet publicly acknowledged the issue.
Some are suggesting that owners use a “finger test” to self-diagnose whether there is an issue with the suspension. There should be four fingers between the tire and the wheel well; anything less than that starts to get dicey.
Tesla Robotaxi riders will face the best dilemma when booking a ride
Tesla Cybercab sightings broaden well outside of Austin with autonomy in focus
