A Dodge Charger Is Running on Next-Gen Battery Cells. The Fine Print Says 'Semi-Solid.'

Stellantis put a Dodge Charger Daytona development vehicle on North American roads this week with a battery pack that most of the EV industry has been promising for a decade: cells that ditch the liquid electrolyte, charge faster, store more energy, and survive extreme temperatures. Factorial Energy's FEST cells delivered 375 watt-hours per kilogram at the cell level, charged from 15% to 90% in 18 minutes, and operated from -22°F to 113°F. This is the first time any solid-state battery technology has been integrated into a real EV in North America.

There is one problem with that sentence: Factorial's cells are not solid-state.

They are semi-solid-state. FEST stands for Factorial Electrolyte System Technology, and the cells retain small amounts of liquid electrolyte between the cathode and the solid separator. The distinction matters because the entire value proposition of solid-state batteries rests on eliminating liquid entirely: liquid is what catches fire, what limits energy density, and what degrades over thousands of charge-discharge cycles until the cell is useless. Keeping some of it around is like building a submarine with a screen door and calling the vessel "mostly watertight."

That said, the car drives, it charges fast, and it works in cold that would hobble a conventional lithium-ion pack. These are not PowerPoint slides or press-release renderings of a vehicle that might exist in 2029. In a field where every company on Earth has missed its production deadline, a test mule on public roads is more progress than most have managed.

The Numbers, Cell vs. Pack

Factorial's headline figure is 375 Wh/kg. That is cell-level energy density, measured before the cells are assembled into a pack with thermal management, a battery management system, structural housing, wiring, and cooling. The pack-level penalty is typically 30-40%, which means the Charger Daytona test mule is likely running at 225-265 Wh/kg at the pack level.

For context: Tesla's 4680 cells in the Model Y deliver roughly 180-190 Wh/kg at pack level, while CATL's Qilin pack, the densest shipping conventional pack in the world, hits about 255 Wh/kg. So Factorial's semi-solid chemistry, in the best case, matches what CATL already ships with regular lithium-ion, and in the worst case, it actually trails CATL by a meaningful margin.

The charging speed is where Factorial genuinely leads. Eighteen minutes from 15% to 90% at 4C discharge is faster than any shipping lithium-ion pack, and if the cycle life holds at scale, that combination of density and speed would be commercially meaningful for fleet operators and road-trip-heavy consumers alike. The company validated 600+ cycles on 77 Ah cells in April 2025, but 600 cycles is roughly two years of daily driving, and an EV battery needs 1,500-2,000 cycles to match a 10-year warranty. Factorial has not published data beyond 600.

The Scorecard Update

We published a solid-state battery broken-promises scorecard tracking every company's original production promise against reality. At the time, the weighted average slippage was 4.3 years. Here is where each company stands now:

A pattern emerges from the table above. The companies making actual physical progress (Factorial driving a car, ProLogium shipping cells, CATL's condensed battery in the Nio ET7) are all semi-solid, while the companies pursuing true all-solid-state chemistry (Toyota, QuantumScape, Samsung SDI) remain stuck in pilot or pre-pilot phases with no vehicle integration to show for billions in cumulative R&D spending. Semi-solid is where the rubber meets the road, literally. True solid-state is where the promises live.

The SPAC Question

Factorial completed its SPAC merger with Cartesian Growth Corporation III this week, and now trades on Nasdaq as FAC at $13.80 with zero revenue and a production timeline that calls for shipping batteries for the Karma supercar in 2027 or 2028.

QuantumScape's SPAC trajectory is instructive. It peaked at a $47 billion market cap in December 2020, when the company had zero revenue, zero production vehicles, and zero independently verified cycle data. Today it trades around $4 billion, still pre-revenue, still with no car on the road. The Eagle Line pilot in San Jose produces cells by the hundreds, not the millions.

Factorial has one advantage over QuantumScape at the same stage: its semi-solid chemistry is compatible with existing lithium-ion manufacturing equipment. True solid-state requires entirely new production lines. Factorial says existing battery producers can make its cells with modifications rather than rebuilds. If true, that collapses the capital expenditure timeline from 3-5 years to 12-18 months. But "if true" is doing a lot of work in that sentence, and Factorial has not named a manufacturing partner or disclosed a factory location.

GM's Quiet Pivot

While Stellantis was driving its semi-solid Charger, GM battery chief Kurt Kelty told Reuters something that got buried beneath the flashier headline: GM may abandon lithium-iron-phosphate (LFP) batteries for EVs entirely. Instead, GM is betting on lithium manganese-rich (LMR), a conventional liquid-electrolyte chemistry that costs about the same as LFP in the U.S. but stores more energy per kilogram.

"There is a possibility where LFP does not earn its way into our portfolio." — Kurt Kelty, GM battery chief

LMR is not solid-state, and it is not even a new chemistry; GM has been working on it for over a decade. But it solves the same problem solid-state promises to solve (more range, same cost) without requiring a revolution in manufacturing. Ford is also developing LMR for future EVs. If LMR works at scale, the economic case for solid-state narrows to niche applications: defense, aerospace, and ultra-fast charging stations where 18-minute fills justify premium pricing that consumer vehicles never will.

The degradation problem looms, however, because LMR cells lose capacity faster with use than NMC or LFP. S&P Global flagged this in 2025 as the primary barrier to mass adoption, and GM has not disclosed its own LMR cycle life data.

The Supply Chain Signal

Buried in the same week's news: NOVONIX delivered the first North American synthetic graphite anode C-sample to Panasonic, a mass-production qualification sample that sits one step from commercial supply. Every battery cell, solid-state or not, needs graphite anodes, and today China controls over 90% of processed graphite supply. A domestic source would remove one of the most acute supply chain vulnerabilities in the entire EV ecosystem, a chokepoint that matters regardless of which cell chemistry ultimately wins.

NOVONIX targets mass production for Panasonic in the second half of 2027. If that holds, it would be the first U.S.-produced synthetic graphite feeding into cells for Tesla (Panasonic's largest customer) and eventually into whatever chemistry wins the next round.

Limitations

This analysis relies on company-reported energy density and cycle life figures that have not been independently verified by a third party. Factorial's 375 Wh/kg and 600-cycle claims are self-reported, and the Donut Lab case earlier this year showed that five independent VTT test reports failed to confirm core performance claims, a cautionary precedent for taking any battery startup's numbers at face value.

Pack-level energy density estimates (225-265 Wh/kg) are inferred from industry-standard cell-to-pack ratios. Stellantis has not disclosed the Charger Daytona test mule's actual pack specifications. The vehicle is a development prototype, not a production configuration.

GM's LMR commentary came from a single Reuters interview and has not been confirmed by formal corporate disclosure.

The Strongest Counterargument

Semi-solid is not a consolation prize. It is the pragmatic path. True solid-state may be physically impossible to manufacture at scale with current materials science. Every sulfide-based approach (Toyota, Samsung) faces the same problem: sulfide electrolytes react with moisture in ambient air, requiring entirely dry-room manufacturing at costs that may never reach parity with liquid lithium-ion. Semi-solid chemistries like Factorial's FEST and CATL's condensed battery sidestep this by keeping just enough liquid to maintain ion conductivity while capturing most of the energy-density benefit. If you need a car on the road in 2027, semi-solid is the only bet that has demonstrated it can get there.