For over a decade, solid-state batteries have been heralded as the next great leap in electric vehicle (EV) technology—a breakthrough that could render today’s lithium iron phosphate (LFP) and nickel manganese cobalt (NMC) chemistries obsolete. Yet despite years of hype and high expectations, that breakthrough remains just out of reach.

Still, the automotive industry isn’t giving up. Global giants like BMW, Mercedes-Benz, and Stellantis continue to invest heavily in solid-state battery development, drawn by the potential of EVs capable of traveling over 1,000 kilometers (621 miles) on a single charge—along with the promise of improved safety, lighter weight, and more efficient packaging.

BMW Charges Forward

BMW is among the most active in the space, recently beginning tests of a specially-equipped i7 prototype fitted with solid-state cells developed by U.S.-based Solid Power. These sulfide-based electrolytes are seen as key to unlocking greater energy density and thermal stability. According to BMW, these cells will play a major role in its upcoming Neue Klasse lineup—though full-scale production likely won’t begin until well into the 2030s.

Mercedes-Benz Takes It to the Streets

Not to be outdone, Mercedes-Benz has also begun real-world testing of solid-state batteries, retrofitting its flagship EQS sedan earlier this year with a pack developed by Factorial Energy. The result? A battery boasting 25% higher energy density than current models, in a more compact and lighter form factor.

“These benefits not only lead to longer vehicle ranges but also affect the vehicle design, for example the architecture,” explained Uwe Keller, head of battery development at Mercedes. “Solid-state cells are also less prone to overheating,” he added—highlighting the improved safety profile that makes this technology so attractive to automakers.

Stellantis Eyes a 2026 Test Window

Stellantis—parent company of brands like Jeep, Peugeot, and Fiat—is also partnering with Factorial Energy on its own solid-state battery push. Road testing is expected to begin in 2026. According to Anne Laliron, Stellantis’ SVP of tech research, “Solid state is the North Star in battery chemistry,” offering automakers a unique tradeoff: more range or fewer materials—both of which contribute to lower costs and reduced carbon footprints.

Japan’s Race to the Finish

While Europe and the U.S. continue testing, Japanese automakers are racing to be first to market. Toyota says it will begin production of solid-state batteries by 2027, with Nissan aiming for a 2028 launch. However, given Nissan’s recent internal struggles, timelines may shift—once again demonstrating how challenging commercialization of this tech can be.

The Road Ahead

Despite slow progress, the stakes couldn’t be higher. If the promises of solid-state batteries hold true—greater range, enhanced safety, faster charging, and better packaging—they could usher in a new era of electric mobility. But until the technology scales economically and proves reliable under mass-market conditions, the dream of a solid-state future remains just that: a dream.

Still, with some of the world’s largest automakers now testing real-world prototypes, that dream may finally be inching closer to reality.

Source: Automotive News