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Tesla battery researchers open path to all-electric range extender concept
Tesla has solidified itself as an industry leader when it comes to electric vehicles and their range. However, an EV’s range could always be improved, and the company has taken great efforts to make this possible. One of these was outlined by Tesla’s battery researchers, who recently published the results of a test that cycles lithium metal on graphite to form hybrid lithium-ion/lithium metal cells. This particular innovation could open the door to an all-electric range extender.
Other automakers have used range extenders in the past, but they’ve been comprised of small petrol-powered engines that are used as a generator to recharge the vehicle’s battery pack when it is low on range. The process of cycling lithium metal on graphite, on the other hand, could lead to a 20% higher energy density than the traditional lithium-ion cells that power the Tesla’s vehicles.
Tesla’s battery research team, led by Jeff Dahn of Dalhousie University, has found a way to create a range extender of sorts without having to keep a small gas engine in the vehicle. Tesla detailed its findings in a research paper that was published to ScienceDirect on April 30. Titled “Cycling Lithium Metal on Graphite to Form Hybrid Lithium-Ion/Lithium Metal Cells,” Dahn and his researchers outlined the testing process.
The findings proved a possible 20% increase in range when using the range extender, which is comprised of “hybrid cells” that use Lithium-Ion and Lithium Metal. The cells also used an optimized electrolyte, and pressure enabled reversible plating on graphite.
The paper states:
“A hybrid anode cell design is proposed involving lithium metal plating on top of graphite that provides a 20% increase in energy density over conventional lithium-ion cells. Pouch cells with hybrid graphite-lithium metal anodes cycled with conventional electrolytes fell below 80% capacity in under 15 cycles. However, with a dual-salt electrolyte and applied mechanical pressure optimized for lithium metal cycling, hybrid cells achieved over 150 full (100% utilization) cycles before falling below 80% capacity with a CE of 99.6% for lithium metal plating on graphite.
“We also found that intermittent high energy (100% utilization) cycles utilizing lithium metal can be dispersed among hundreds of conventional lithium-ion cycles where only the graphite is utilized. Operating the cell with this intermittent protocol shows minimal impact to the underlying graphite capacity. Therefore, these hybrid cells can operate well in “lithium-ion mode” with periodic high energy full cycles accessing the lithium metal capacity.”
Tesla’s new findings show that increased energy density is made possible with the hybrid concept. When combining lithium-ion cells with lithium metal, energy density improves as the graphite anode utilized in traditional lithium-ion cells is not capable of handling the increased energy. The utilization of a dual-salt electrolyte also increases density and decreases battery cell degradation.
Tesla’s battery researchers described the advantages of the hybrid lithium-ion/lithium metal cells in the discussion below.
“If an electric vehicle with a conventional lithium-ion battery can deliver a range of 400 km, then hybrid cells could enable a range of 480 km. By capping the upper cut-off voltage of hybrid cells to operate in lithium-ion mode, the average cell voltage and delivered capacity will decrease. As a result, operating a hybrid cell in lithium-ion mode delivers an energy density of 530Wh/L, about 25% less than a conventional lithium-ion cell.
“This would result in a range of 300 km. In a study of driving behavior for EVs, Smart et al.34 showed that only 1% of daily trips are longer than 325 km on average. Therefore, operating hybrid cells most of the time in lithium-ion mode enabling a range of 300 km, while periodically using the lithium metal portion for long > 400 km trips, as mimicked by this testing protocol, should be viable for most drivers.”
It should be noted that the Tesla battery researchers’ study is only in their initial stages. Thus, it may take some time before the technology gets rolled out to Tesla’s fleet. The wait would likely be worth it though, as the hybrid cells could open the door to all-electric vehicles with range extender features. This would be incredibly useful for electric vehicle owners who take long road trips with family, and it could also be a notable step towards EVs gaining range parity with their petrol-powered counterparts.
The Tesla Semi is entering a new Pilot Program with Paper Transport, LLC (PTI), a Wisconsin-based transportation provider. The company will test the Semi’s Long Range configuration through “dedicated operations within the Chicago market.”
Chicago presents an interesting challenge for the Semi, as it will be a colder-weather climate that will test the Semi’s ability to operate in lower temperatures and in potentially large accumulations of snow. This is something Tesla has been testing with the Semi in Alaska and even in Northern California during the colder months, but Chicago will present a truly tough midwestern winter.
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PTI says it is using the Semi to evaluate its strategy of reducing transportation emissions while maintaining performance, reliability, and cost efficiency. These are major arguments for the Semi being introduced into new fleets.
CEO of PTI Tyler Ellison said:
“PTI has been a leader in sustainable transportation solutions for over 15 years. We take a consultative approach to helping customers identify and implement the right transportation solution for their network. Our partnership with Tesla expands our portfolio alongside renewable natural gas and intermodal, giving customers more ways to reduce Scope 3 emissions without compromising service or economics.”
PTI is far from the first company to adopt the Semi within a fleet, as Tesla entered strategic agreements with PepsiCo. and its subsidiary Frito-Lay for a Pilot Program that extended throughout the California region.
Tesla has let companies like those utilize the Semi to determine whether it would be suitable for their operations. Additionally, Tesla gets valuable information regarding the Semi’s performance, knowing what to improve and what is ideal for companies that will utilize the all-electric truck for regional and nationwide logistics.
PTI plans to utilize the Long Range configuration, which is priced at $290,000 and features a range of approximately 500 miles, a three-motor powertrain, up to 800 kW of drive power, and consumption of just 1.7 kWh per mile.
Tesla Semi pricing revealed after company uncovers trim levels
VP of Maintenance at PTI, Bryan Ellen, added:
“We are excited to partner with Tesla, leveraging their ever-evolving technology. We are bullish in our estimation of the parallels available between our dedicated model and the efficiency of their fully electric Class 8 tractor. We anticipate a growing synergy between our businesses as we work to facilitate this sustainable solution for our customers.”
PTI has logged more than 87 million miles using sources like compressed and renewable gas, but now is looking to take it a step further with fully electric operations.
Tesla revealed on Monday that it is building a new autonomous vehicle at Gigafactory Texas, its plant just outside of the City of Austin. This particular vehicle will be geared toward those who are in need of a wheelchair-accessible car that would require no human driver for operation.
According to a new report from Wired, Tesla’s Senior Policy Advisor, India Herdman, told members of the Washington D.C. City Council on Monday:
“We are in development for a purpose-built, wheelchair-accessible autonomous vehicle. We know that paratransit can be very difficult, and people who are confined to wheelchairs permanently should still be able to move around freely, so that is an active product being built by Tesla in Texas.”
This builds upon what CEO Elon Musk said last year on X, which confirmed the company was working on accessible rides within its Robotaxi platform, which currently is confined to the Model Y.
Absolutely
— Elon Musk (@elonmusk) September 19, 2025
Tesla is also developing the Cybercab, which started employee rides last week. However, this vehicle is not necessarily geared toward wheelchair accessibility.
That leaves a major gap in the autonomous ride-sharing program that Tesla is attempting to build; the company has been pretty clear that it does not want to complicate its manufacturing lines by bringing in a wide array of body styles.
However, it seems necessary to have something larger that could help transport people to appointments when they cannot drive. For wheelchair accessibility, the Robovan, which was unveiled at the “We, Robot” event in October 2024, seems to be the most ideal solution:
Herdman did not indicate whether she was referring to the Robovan or if Tesla is building yet another body style that is geared toward full autonomy but also caters to the handicapped.
Tesla might need to develop something specifically for the handicapped in order to align with the Americans with Disabilities Act, which prevents discrimination against people with disabilities in transportation services. Uber was hit with a lawsuit late last year for “refusing to reasonably modify its policies, practices, or procedures where necessary to avoid discriminating against riders with disabilities.”
Tesla would obviously like to avoid this.
It will be interesting to see what Tesla will do with this project, and whether it will introduce something new to the market or just continue with the Robovan.
Tesla weirdly confirmed that its steering wheel-less and pedal-less Cybercab vehicle is now in the process of giving employees rides, a huge milestone for the vehicle program.
But the entire thing was super strange. On Friday, Tesla released a video stating that there was “Cool news from Giga Texas” and that employees were now taking rides in Cybercabs that have no manual controls. The units seen on public roads are engineering vehicles that have manual controls inside, a necessity as Tesla moved through the testing phase.
However, Tesla removed the video and reposted it shortly after with a more vague title. It seems like the employee rides are still going, but the video was adjusted slightly. The initial upload showed employees doing things like watching movies and adjusting the climate, but these snippets were removed in the second upload.
Cool news from Giga Texas pic.twitter.com/gvbG456Tzw
— Tesla Robotaxi (@robotaxi) July 11, 2026
Both images below were uploaded with the first video, but were removed after Tesla re-uploaded the announcement. These are not available in the second upload
Credit: Tesla
Credit: Tesla
Nevertheless, the announcement from Tesla is that the Cybercab is operating with employees inside who can control the vehicle’s audio, video, climate, and destination settings through their smartphone app.
Tesla has already been testing Cybercab engineering units, but last month, it was able to self-certify for SAE Level 4, which would enable unsupervised self-driving in Texas. The company is moving toward that, and the plans have always been to launch Cybercab rides this year.
The Cybercab is potentially looked at as the next generation of Tesla’s mobility leg. For the past 15 years, the company has been known as somewhat of an automaker, among many other things. However, these passenger vehicles that Tesla has manufactured are now moving into a new realm, as they will eventually drive themselves with no supervision thanks to the Full Self-Driving suite.
The Cybercab is just the next step of that: a true vehicle developed for the sole purpose of ride-hailing. It has no human controls, it has only two seats, and it will get passengers from Point A to Point B with no awkward driver, no need for manual inputs, and with no stress.
Tesla is moving forward with other developments related to the Cybercab project as well. However, the big announcement will come when Tesla finally announces that it is launching Cybercab rides to the general public, something that it plans to launch either late this year or early 2027.
Tesla Semi enters new Pilot Program with interesting challenge
Tesla is building a wheelchair-accessible Robotaxi
