Slate's cheap EV truck got better the moment Washington stopped caring where its battery came from

In April 2025, Slate Auto's CEO told a reporter exactly why her stripped-down electric truck would not use the cheapest, most durable battery chemistry available. "We've gone with more of what's in the mainstream right now," Chris Barman said, explaining the choice of nickel-manganese-cobalt cells over lithium-iron-phosphate. The real reason sat one sentence later: "For LFP, most of those materials would come out of China or elsewhere." A federal tax credit worth $7,500 was on the line, and LFP's supply chain didn't qualify.

Fourteen months later, that $7,500 credit no longer exists. And Slate's truck now runs on LFP batteries from a Chinese supplier, built at a factory in Illinois.

The bigger argument here isn't really about battery chemistry. It's about how much of what gets called "American manufacturing strategy" in the EV industry was actually built around a single piece of legislation, and how fast that strategy reversed the moment the legislation vanished.

Start with what changed on paper. Slate originally signed a deal with South Korea's SK On for NMC cells, partly because the battery tax credit rules under the Inflation Reduction Act required increasingly strict North American sourcing, with anything tied to a "foreign entity of concern" disqualified outright. China controls roughly 98% of the world's supply of active materials for LFP batteries, so going with LFP and keeping the credit were close to mutually exclusive. Slate chose the credit. Then, in 2025, the One Big Beautiful Bill Act eliminated the $7,500 incentive entirely. The constraint that had ruled out LFP simply stopped existing, and Slate's president of vehicles told InsideEVs the policy shift "gave Slate the flexibility to explore other battery options", a notably understated way of describing a complete reversal of the company's founding battery strategy.

The technical case for LFP turns out to be stronger than the political case ever was. LFP cells cost about 40% less than NMC, largely because iron replaces the pricier nickel and cobalt, and a cell-to-pack design, stacking cells directly into the pack without the usual module step, boosted volumetric energy density enough to offset LFP's lower energy-per-kilogram disadvantage. The result: Slate's range actually went up, from 150 miles to 205, even as it switched to a supposedly weaker chemistry. Slate's head engineer, Eric Keipper, said landing on 205 miles felt like the right tradeoff: "Being in that sweet spot, it felt like a good place to just have a single battery and read the room from there." The larger 240-mile NMC option Slate once promised is gone, LFP's lower density meant there wasn't room in the truck's small underbody to scale up to that range, so Slate cut the option rather than the chemistry.

Here's the part worth sitting with: the switch makes the truck objectively better for almost everyone who'll actually drive it. LFP cells tolerate being charged to 100% repeatedly without the degradation NMC suffers under the same treatment, meaning owners can use their full range daily instead of capping at 80% out of habit. The packs are also expected to last 500,000-plus miles if thermal management holds up, for a vehicle built to be a daily commuter, not a road-trip machine, that's a better fit than the chemistry it replaced.

The complication is the one nobody at Slate is eager to discuss out loud: durability and cost only improved because a domestic-sourcing rule disappeared, not because Slate found a clever workaround to it. If the tax credit were reinstated tomorrow with the same sourcing requirements, the calculus would likely flip back. None of the engineering logic changed between April 2025 and June 2026, only the law did. That's a useful reminder for anyone reading a company's stated "strategy" as if it reflects engineering conviction rather than the regulatory environment of the moment it was announced in.

Slate's reservation holders mostly don't care about any of this. On Slate's own owner forums, the most common reaction to losing the 240-mile option wasn't anger, it was a shrug: most people drive under 15 miles a day, and 205 miles was never the constraint anyone was actually living with. The truck's first ride reviews, including a writer who called the prototype "insanely fun" at $24,950, suggest the chemistry swap landed exactly where it needed to: invisible to the buyer, decisive for the spreadsheet. Slate didn't set out to make a statement about battery geopolitics. It just built the cheapest truck it could once the rules that were holding it back from doing so stopped applying. Read more on how Slate priced the truck itself, the battery decision is the part of that story that didn't make the press release.