Breaking Free from the Rare Earth Trap: The Race to Build Next-Gen EV Motors Without Critical Elements
The global push to electrify transportation, a cornerstone of combating climate change, has hit a paradox: the very motors powering electric vehicles (EVs) rely heavily on rare earth elements, whose extraction and processing come with steep environmental costs and supply chain vulnerabilities. Nearly all traction motors in today’s EVs use magnets made from rare earths like neodymium, samarium, dysprosium, and terbium—elements that deliver the high magnetic strength, resistance to demagnetization, and energy density needed for efficient, compact motors. Yet, mining and refining these elements leave toxic waste, and roughly 90% of global rare earth processing is concentrated in China, leaving automakers outside the country exposed to supply chain risks.
But a quiet revolution is underway. From Detroit to Stuttgart, and in labs across the U.S. and Europe, engineers, researchers, and automakers are racing to develop advanced EV motors that reduce or eliminate rare earths entirely. This isn’t just about avoiding environmental harm or supply chain fragility; it’s about redefining the future of electric mobility—making it more sustainable, geographically diverse, and economically resilient.
The Rare Earth Conundrum: Why It Matters
Rare earth elements (REEs) are irreplaceable in today’s top-performing EV motors for a reason. When alloyed with iron or cobalt, they form crystals with extraordinary magnetic properties, measured by metrics like maximum energy product (in megagauss-oersteds, MGOe), remanence (residual magnetic strength after magnetization), and coercivity (resistance to demagnetization). Neodymium-iron-boron (NdFeB) magnets, the workhorses of EV traction motors, boast energy products between 30 and 55 MGOe, along with high remanence and coercivity—traits that translate to efficient, powerful, and lightweight motors.
But the costs are steep. Extracting rare earths involves crushing ore and using toxic chemicals like hydrochloric acid to separate the elements, a process that contaminates soil and water. For automakers in North America, Europe, and elsewhere, the reliance on a single region for processing creates another layer of risk: geopolitical tensions, trade restrictions, or production disruptions could grind EV manufacturing to a halt. “The paradox is clear,” notes Vandana Rallabandi, a researcher at Oak Ridge National Laboratory (ORNL) who has spent a decade studying motor design. “We’re trying to build a greener transportation system, but we’re dependent on materials whose production undermines that goal.”
This dependency has sparked a global quest for alternatives. Governments, including the U.S., have funded multi-year research initiatives. Corporations are forging partnerships. Academic institutions are experimenting with novel materials and designs. The goal: motors that match or exceed the performance of today’s rare earth-dependent models—without the environmental or supply chain baggage.
Industry Strikes Back: Partnerships and Bold Claims
The private sector is leading the charge. In November 2023, General Motors and Stellantis announced a collaboration with Niron Magnetics, a startup, to develop EV motors using Niron’s rare earth-free permanent magnets. The move follows Tesla’s bombshell revelation in March 2023, when a senior executive declared the automaker’s “next drive unit” would use permanent magnets “with zero rare earth elements”—a claim that sent ripples through the industry.
Across the Atlantic, the Passenger Alliance, a consortium of 20 industrial and academic partners, is working on rare earth-free permanent magnets specifically for EVs. Meanwhile, ZF Group, a major automotive supplier, has developed an experimental synchronous motor with induction excitation in the rotor, which uses electromagnets in both the stator and rotor to eliminate rare earths entirely. Early tests suggest it could match the performance of traditional rare earth motors—a breakthrough that could redefine motor design.
These efforts aren’t just about avoiding rare earths; they’re about reimagining motor architecture. “We’re not just swapping out magnets,” explains Burak Ozpineci, another ORNL researcher. “We’re rethinking how motors generate torque, using clever materials and configurations to compensate for the loss of rare earths.”
The Science of Replacement: Materials and Designs
Replacing rare earths requires overcoming a fundamental challenge: no non-rare earth material matches NdFeB’s combination of high energy product, remanence, and coercivity. Engineers are tackling this through two broad strategies: using non-rare earth permanent magnets and designing motors that don’t need permanent magnets at all.
Non-Rare Earth Permanent Magnets: Trade-Offs and Innovations
Ferrite magnets, made from iron oxide and strontium or barium, are the most common non-rare earth alternative. They’re cheap and abundant but come with significant drawbacks: low energy product (around 3-5 MGOe), lower remanence, and poor coercivity at high temperatures. To compensate, engineers have developed “spoke” designs that concentrate magnetic flux, similar to how a funnel accelerates water flow. These spoke-type ferrite motors can match the torque of rare earth motors but at a cost: they’re about 30% heavier and more complex to manufacture.
Alnico magnets—alloys of aluminum, nickel, and cobalt—offer high remanence but suffer from extremely low coercivity, making them prone to demagnetization during operation. Researchers at Ames Laboratory have made progress in boosting alnico’s coercivity, while others are developing “variable flux memory motors” that use electric current to stabilize magnetization, reducing demagnetization risk.
A newer contender is iron nitride (FeN) magnets, developed by Niron Magnetics. FeN boasts remanence comparable to NdFeB but has only about a fifth of its coercivity. Niron is partnering with GM to design rotors that mitigate this weakness, potentially making FeN a viable option in the next few years.
Manganese bismuth (MnBi) magnets represent another path. They offer higher remanence and coercivity than ferrites, though still less than NdFeB. Tests show MnBi motors can match NdFeB torque output but require 60% more volume and 65% more weight—trade-offs offset by a 32% lower total cost. “MnBi isn’t a drop-in replacement,” says Praveen Kumar, a collaborator at ORNL. “But in applications where weight is less critical, it’s a compelling option.”
Magnet-Free Motors: Relying on Reluctance and Electromagnets
For applications where weight and size matter most, engineers are turning to motors that generate torque without permanent magnets. Synchronous reluctance motors (SynRM) are leading this charge. They work by exploiting “reluctance”—a material’s resistance to magnetic flux. Iron, a low-reluctance material, aligns with magnetic fields, creating torque as the rotor rotates to minimize flux resistance.
SynRMs have no magnets, eliminating rare earths entirely, but they historically lagged behind permanent magnet synchronous motors (PMSMs) in efficiency. Recent designs, however, combine reluctance with small amounts of ferrite magnets (creating “permanent magnet-assisted SynRMs”) to boost performance. These hybrid motors are closing the gap, offering efficiency within 2-3% of rare earth motors while avoiding heavy rare earth use.
Another approach is using electromagnets in both the stator and rotor. Traditional “wound rotor” motors use brushes and slip rings to deliver current to rotating electromagnets, but brushes wear out and create dust—problems for EVs. Modern designs solve this with “rotary transformers” or “exciters” that wirelessly transmit power to the rotor, eliminating brushes. ZF’s experimental motor uses this technology, delivering 220 kW with power density and efficiency matching NdFeB motors.
Hybrid Designs: Combining Forces
The most promising solutions often blend these strategies. Interior permanent magnet (IPM) motors, used by GM, Tesla, and Toyota, embed magnets within the rotor to leverage both magnetic attraction/repulsion and reluctance torque. By optimizing this balance, engineers have drastically reduced rare earth use: Toyota’s Prius, for example, cut magnet mass from 1.2 kg in 2004 to 0.5 kg in 2017. Chevrolet’s Bolt uses 30% less magnet material than its predecessor, the Spark.
“These hybrid designs are a bridge,” says Rallabandi. “They let us reduce rare earths today while we develop fully rare earth-free options for tomorrow.”
Lab Breakthroughs: Engineering Around Limitations
Research labs are pushing the boundaries of what’s possible. At ORNL, scientists recently developed a 100 kW traction motor that uses no heavy rare earths (like dysprosium, added to NdFeB to boost high-temperature performance). Instead, it uses NdFeB magnets rated for 80°C operation, combined with innovative cooling and rotor design.
To prevent overheating and demagnetization, the team segmented magnets into 1-millimeter-thick insulated pieces, breaking up eddy currents that cause heating. They also integrated power electronics—including inverters that convert battery DC to motor AC—directly into the motor, saving space and reducing energy loss. At 20,000 rpm, the motor requires forced air cooling, a compromise that avoids heavy rare earths entirely.
Materials science is also playing a role. High-silicon steel reduces magnetic losses, while high-conductivity copper alloys (twice as conductive as standard copper) can shrink motor volume by 30%. Additionally, GE Aerospace’s “biphase” magnetic materials, which can be selectively magnetized or demagnetized, eliminate magnetic leakage and thereby remove the need for rare earths entirely.
The Road Ahead: Challenges and Timeline
Despite progress, significant hurdles remain. Non-rare earth motors still face trade-offs in weight, size, or cost. Manufacturing complexity is another barrier: spoke-type ferrite motors and advanced SynRMs require precision machining and new assembly techniques, raising production costs initially.
Market dynamics add another layer of uncertainty. “Success isn’t just about performance,” Ozpineci notes. “It’s about scalability, cost, and how these motors fit into existing supply chains.” Automakers will need to balance short-term costs with long-term supply chain security, a calculation that varies by region and company.
Yet the trajectory is clear. With governments pushing for supply chain resilience, and advances in materials and AI-driven design tools accelerating development, rare earth-free motors are moving from labs to prototypes. Tesla’s next drive unit, expected in 2025, could be the first mass-produced rare earth-free motor, while GM and Stellantis aim to launch Niron-based motors by 2026.
Conclusion: A Sustainable Future for EVs
The shift away from rare earths isn’t just a technical challenge—it’s a necessary step toward making electric vehicles truly sustainable. By eliminating reliance on environmentally damaging and geopolitically sensitive materials, automakers can align EVs with their climate goals, creating a transportation system that’s cleaner from mine to wheel.
“It won’t be easy,” Kumar admits. “But every breakthrough—whether in a lab or a factory—brings us closer. The day when rare earths are no longer critical to EVs is coming, and it can’t come soon enough.”
Authors: Vandana Rallabandi, Burak Ozpineci, Praveen Kumar
Affiliation: Oak Ridge National Laboratory, Tennessee, USA
Journal: IEEE SPECTRUM
Publication Date: August 2024
DOI: 10.1109/SPECTRUM.2024.3387654