It wasn’t long ago that solid-state batteries were the hottest new EV technology, promising longer ranges, faster charge times, and other benefits versus lithium-ion. However, despite extensive ongoing investments from automakers, optimism has cooled as the tech’s potential seemingly remains far from reality. As Julia Poliscanova of Transport & Environment told CNBC in October 2024, “…every time I speak with automotive executives at battery conferences, I keep hearing the same answer: ‘We are five to seven years away.’”
That quote got me thinking about where solid-state EV batteries are at in their development and when we might see their potential realized. I did some digging to find the current state of solid-state batteries, including the pros and cons, the reason for slow development, which automakers are most invested in the technology, and whether any alternatives are on the horizon. To start, though, I’ll quickly recap what solid-state vehicle batteries are and why they drew so much buzz in the first place.
What Are Solid-State Batteries?
The solid-state battery, which began serious development in the late 20th century, is considered the next frontier of battery technology. Traditional batteries, including the popular lithium-ion batteries that currently power EVs, use liquid electrolytes to connect the electrodes. Conversely, solid-state batteries have solid electrolytes, which were discovered by legendary English chemist Michael Faraday in the early 1830s.
Unfortunately, existing technologies were too primitive for Faraday to utilize solid electrolytes in his lifetime. The first significant solid-state battery, which could power a watch, wasn’t created until 1986 by Keeichi Kanehori. Multiple other researchers took up the mantle, with the late John Goodenough—the same person who co-invented the lithium-ion battery—among those who introduced larger, workable solid-state battery models in the 2010s.
The Pros of Solid-State Batteries
When you look at the possible benefits of solid-state batteries, it’s easy to see why they became such a hot topic. The main advantages are that solid-state batteries theoretically last longer and go farther. One battery pack developed by Volkswagen and QuantumScape only lost 5% of its capacity after 1,000 charge cycles, which is over four times better than the current lithium-ion standard. The denser energy storage also offers more range than a lithium-ion battery of the same weight—estimates range from a 30% increase to doubling the range.
Solid-state batteries also charge faster. While even the best lithium-ion EV batteries still take 20-40 minutes to reach an 80% charge with a Level 3 charger, an equivalent solid-state battery could theoretically take less than 10 minutes to charge. A solid-state battery can also handle higher operating temperatures and is less flammable. Finally, since you don’t need to mine lithium to make a solid-state battery, they are theoretically cleaner to manufacture. Research by Transport & Environment indicates solid-state batteries could lower an EV’s total carbon footprint by 39%.
Why Has Adoption Been So Slow?
Solid-state batteries are already becoming widespread in smaller items like pacemakers and smartwatches. Yet despite the obvious advantages, we are unlikely to see any vehicles using them for at least a few more years. Despite recent advances, the technology is still relatively new, and there are several challenges to overcome.
One is that the batteries swell during the recharging process. Over time, this can cause the solid electrolytes to degrade, thus eliminating the theoretical longer-life benefit. This can happen sooner in extreme cold, which is a problem for EVs in northern environments. There is also the issue of the formation of dangerous dendrites—crystal-like growths that can puncture the battery from within. As such, the battery designs must be re-engineered for better dendrite resistance while preventing degradation from swelling and cold weather. Further testing also needs to be done to ensure solid-state batteries can handle everyday road stresses without safety issues.
Perhaps most significantly, cost remains a huge barrier. The materials, equipment, and production process cost much more than lithium-ion batteries, and the production of solid-state batteries still needs to be scaled up. Until costs fall, solid-state batteries will most likely be limited to luxury models.
Which Automakers Are Working on Solid-State Batteries?
Despite the hurdles, some big automotive names are plowing forward with solid-state battery development—and a few have already entered pilot production. Here’s a brief overview of where each currently stands and a possible timetable for when their first solid-state battery vehicles may be released.
Toyota
In late 2023, Toyota partnered with Idemitsu Kosan—a Japanese oil company that has been developing solid-state battery technology since 2001—to develop and produce vehicles containing the batteries. Toyota’s stated goal is to release its first commercial solid-state battery EVs by 2028. Purportedly, their aim for the battery is a 900-mile range and 10-minute charging time. The goal is to start small, with an initial run in the tens of thousands before building up to mass production.
Honda
After being late to the EV party, Honda is trying to make up ground on the battery front. It has stated it hopes to release its first EV with a solid-state battery in the second half of the 2020s, although no official target date or vehicle model is set. Honda is trying to combat the dendrite growth problem by surrounding the electrolyte with a roll-pressed polymer fabric buffer to improve resistance and control battery thickness. Also, it is aiming to have mass production set up from the initial release rather than a slow roll-out.
Nissan
Nissan demonstrated its pilot production line for solid-state batteries in April 2024. Its goal is to have its first solid-state EVs on the market by 2028 or 2029. Although the specifics have been scarce, Nissan is doing all research and development in-house and plans to use the batteries across most vehicle segments. It may even integrate the technology into larger city development.
Mercedes-Benz
Several automakers have partnered with Factorial to develop solid-state batteries, including Stellantis, Kia, and Hyundai. Mercedes-Benz is the most recent, announcing a partnership in September, which includes direct investment in the start-up. Their stated goal for the “Solstice” battery is an energy density of 450 Wh/kg, which would produce a range 80% higher than the current average. They currently think Solstice will be ready by 2030.
Volkswagen
After months of delays, Volkswagen formalized its agreement with QuantumScape in July. QuantumScape is licensing its existing solid-state battery formula to VW’s internal PowerCo division, and they will join forces to test and fine-tune the final product so it can be mass-produced for a to-be-determined vehicle. The deal calls for one million EVs, but no target date has been announced.
The Future of Alternative Vehicle Power
As you can see, it’s going to be a little while before EVs with solid-state batteries are available—and likely even longer before they’re affordable for most drivers. The good news is that solid-state isn’t the only battery technology advancing by leaps and bounds. Lithium-ion batteries continue to get more efficient, and several companies are working on batteries that use more sustainable cathode materials than the cobalt that is currently predominant. These include lithium-sulfur batteries and nickel-aluminum blends.
Then there’s the semi-solid-state battery. Factorial is one of the companies developing batteries with a hybrid of solid and liquid electrolytes. They estimate this design increases range by about 40% compared to current lithium-ion batteries—and semi-solid-state batteries can be made on existing lithium-ion production lines, making them far easier to scale up. Factorial predicts the first vehicles with semi-solid-state batteries will be commercially available by 2026, serving as a bridge to eventual all-solid-state EVs. It’s one more thing to watch as EV tech continues to power forward.
