GM's World-First LMR Bet: Prismatic Manganese-Rich Cells to Enter Production at Spring Hill by 2028

Introduction

In the rarest category of industrial news — a company committing real money to a battery chemistry that does not yet exist in volume production — General Motors has moved first. Ultium Cells, the joint venture between GM and LG Energy Solution, announced on September 28 that it will upgrade its Spring Hill, Tennessee plant to manufacture prismatic lithium manganese-rich, or LMR, battery cells. Facility modifications begin later this year and are expected to finish in 2028, with first vehicle shipments anticipated around the same time.

If the schedule holds, Spring Hill becomes the first facility anywhere to mass-produce prismatic LMR cells. The claim is not trivial. Ultium says the chemistry delivers roughly 33 percent more energy density than lithium iron phosphate, the dominant low-cost chemistry in electric vehicles today, at a comparable cost. That combination — more energy for the same money — is precisely the claim that has eluded the battery industry for three decades, and it explains why this announcement matters well beyond one plant in Tennessee.

The stakes are larger than a single product cycle. As CleanTechnica reported, manganese is abundant and cheap where nickel and cobalt are neither, and LMR sits as a middle path between today's affordable LFP cells and expensive high-nickel chemistries. This is a story about which chemistry sets the floor on battery cost, and which manufacturer gets to define it. For background on the wider storage build-out, our coverage of battery tech tracks the grid-scale side of the same supply chain.

Main Content

What Ultium Actually Announced

The specifics matter, because the announcement is narrower — and more credible — than the marketing suggests. Per the Ultium Cells newsroom, the company will upgrade its existing Spring Hill facility, a roughly 30-minute drive south of Nashville, rather than build something new. The upgrade adds LMR prismatic production to a site that already runs LFP cells for stationary storage and hosts high-nickel lines.

The investment figure has moved during reporting. Local coverage in WSMV and the Nashville Tennessean put the near-term commitment at $1 billion, with Ultium stating the combined LFP and LMR programs plus site improvements reach $1 billion by 2030. Spring Hill's cumulative investment now stands at roughly $3.5 billion after the 2021 joint-venture announcement and a 2022 expansion. The expansion adds 500 jobs to a current workforce of about 1,200, bringing the site to around 1,700 people.

Two caveats deserve emphasis. First, Ultium publishes no absolute Wh/kg figure for its LMR cells — the 33 percent number is a relative claim against LFP, and electrive.com notes the company declines to give specific energy density values. Second, "world's first" describes a production line, not a discovery. GM and LG Energy Solution announced the LMR program in May 2025 and said at the time that commercial production was targeted for 2028, with pre-production at an LG Energy Solution facility by late 2027.

Why Manganese-Rich Has Stalled for Thirty Years

The chemistry was not discovered recently. Lithium-rich manganese-based cathode materials have been studied since the 1990s, and the theoretical case is straightforward: drop nickel and cobalt, two expensive and difficult-to-process metals, and raise the manganese content. Energy density and cost should both improve.

As InsideEVs reported on Ford's parallel effort, three problems kept the chemistry on laboratory shelves for three decades. Voltage attenuation means substantial loss of operating voltage over time. Severe capacity loss follows, which cuts usable energy and degrades thermal stability. And high initial working voltage, one of the chemistry's genuine advantages, is also what drives oxygen-related degradation inside the cathode. Oxygen reactions help LMR store energy, but if they fail to reverse during discharge, they damage the cell structure and generate gas — an unwelcome development inside a tightly packed automotive cell.

That is a physics problem, not a manufacturing one, which is why it took this long. LG Energy Solution and Seoul National University recently reported experimental cells retaining 92.2 percent of initial capacity after 883 charge-discharge cycles, against an EV design life of 1,000 to 2,000 cycles. The team lowered the charging cutoff from 4.6 to 4.3 volts, improved oxygen recovery from 86 percent to 97 percent, allowed discharge down to 2.0 volts instead of 3.0, and added a lower-temperature formation step. Seoul National University's Professor Jongwoo Lim described the finding as showing that cell stability can be improved through electrochemical protocol design alone. Notably, neither charging speed, cold-weather performance, nor real-world longevity has yet been demonstrated against production LFP.

Ford Is Not Standing Still

The competitive subtext is easy to miss and it favors nobody. Ford is developing LMR at its Ion Park research center in Romulus, Michigan, and is already running a pilot line producing second-generation LMR cells, according to InsideEVs. Ford's director of electrified propulsion engineering, Charles Poon, framed the chemistry as the answer to what comes after NMC in 2023 and LFP since — and tied it to cost parity with combustion vehicles rather than merely to performance.

GM's counter is portfolio breadth. Kurt Kelty, GM's vice president of battery and sustainability, told Electrek that high-nickel cells remain the range leaders while LMR lets GM "leapfrog today's more affordable chemistries." The Spring Hill site will run high-nickel, LFP and LMR in both pouch and prismatic formats under one roof. Notably, the LFP cells produced there since June 2026 go to stationary storage customers, not vehicles — a sign that GM has been willing to reassign its lowest-cost chemistry to wherever demand actually is.

The Chemistry and Its Cost Logic

The structural logic of a prismatic cell explains why this format matters commercially rather than merely technically. Electrive's technical illustration of prismatic cell internals shows the layered electrode stack inside a rigid housing, with terminals on the top plate. Prismatic cells pack into modules with higher volumetric efficiency than cylindrical formats because they eliminate the round-cell interstitial gaps — the wasted space that limits how tightly a pack can fill a vehicle floor or a shipping container.

Manganese is element 25 on the periodic table, an abundant crustal element that occurs in dozens of oxide minerals. That abundance is the entire economic argument. Cathode materials dominate cell cost, and moving volume share from nickel-manganese-cobalt toward manganese-rich formulations shifts the cost curve at the bottom of the stack. When the University of California, Santa Barbara's Institute for Energy Efficiency framed GM's program in July 2025, it cast LMR as a competitive response to Chinese dominance of LFP — the low-cost chemistry that was once an American invention but whose volume market was captured elsewhere. GM's own framing is blunter: bringing this cell to market first, per GM News, is a milestone for keeping America competitive in EV and battery technology leadership.

What Could Go Wrong

The most honest reading of the timeline is that this is a 2028 story that starts in 2026. Retrofit work begins late this year and completes in 2028; pre-production at an LG Energy Solution facility is expected by late 2027; first GM vehicles arrive in 2028. Automotive programs of this type routinely slip. LMR's known weaknesses — durability, capacity fade and limited fast-charging capability — are precisely the properties a truck or full-size SUV application cannot tolerate. GM has said it intends the cells for pickups and large SUVs, targeting more than 400 miles of range, while its high-nickel Silverado EV currently reaches an estimated 478 miles and starts at $55,895. If LMR delivers on cost but falls short on charge speed, the line still runs; the market fit is what carries the risk.

There is also the question of whether the demand case still holds. GM pulled back on its EV lineup after the federal $7,500 credit was eliminated, and its pivot into stationary LFP storage was a defensive one. Committing a billion dollars and 500 jobs to a chemistry aimed at affordable EVs in that environment is a bet that demand recovers — and that GM intends to be the one supplying it cheaply when it does.

Conclusion

Spring Hill will not make lithium manganese-rich the default chemistry. That judgment belongs to CATL, BYD and the broader supply chain, and China's control of LFP manufacturing remains the benchmark Ultium is trying to beat. What the announcement does establish is that the gap between an LFP cell and a high-nickel cell — the trade-off that has defined EV battery strategy for a decade — now has a credible third option, and that an American plant is betting production capacity on it before the chemistry is fully proven at scale.

The reason to watch 2028 closely is not the ribbon-cutting. It is whether 883-cycle laboratory durability translates into a truck that charges fast, holds range in cold weather, and can be sold profitably. Ultium has committed the capital and the headcount. The physics, as LG's researchers have shown, is solvable but not solved. Whether it is solved at automotive volume, on a retrofit line in Tennessee, will be the real test of whether the third option sticks.

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References

• Ultium Cells — Ultium Cells to Upgrade Spring Hill Operations to Produce Lithium Manganese-Rich (LMR) Prismatic Battery Cells
• General Motors — Ultium Cells to bring LMR prismatic battery cell production to Tennessee for future GM EVs
• electrive.com — Ultium Cells retrofits Tennessee plant for LMR cell production
• Electrek — GM's new EV battery tech will cut costs without sacrificing performance or range
• CleanTechnica — GM Really Wasn't Kidding About Those New LMR EV Batteries
• InsideEVs — Ford Develops Breakthrough Battery Chemistry After 'Intense Research'
• WSMV — $1 billion investment to make Middle Tennessee facility 1st in world to mass produce 'breakthrough battery technology'
• InsideEVs / Yahoo Autos — LG's Experimental LMR Battery Retained 92% Capacity After 883 Cycles
• Institute for Energy Efficiency, UC Santa Barbara — GM's Home-Grown LMR Battery Opens New Front in EV Competition
• Wikimedia Commons — Lithium Ion Battery Cell formats, Prismatic cell internals, Manganese oxide rock, EV battery pack illustration