Lithium iron phosphate comes to America - C&EN

 

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In brief

Electric car companies in North America plan to cut costs by adopting batteries made with the raw material lithium iron phosphate (LFP), which is less expensive than alternatives made with nickel and cobalt. Many carmakers are also trying to reduce their dependence on components from China, but nearly all LFP batteries and the raw materials used to make them currently come from China. A number of companies are now planning the first large-scale LFP factories in North America. Some are partnering with established companies, and others hope to introduce new technologies that will leapfrog Chinese competitors.

On a bookshelf in his home near Montreal, Denis Geoffroy keeps a small vial of lithium iron phosphate, a slate gray powder known as LFP. He made the material nearly 20 years ago while helping the Canadian firm Phostech Lithium scale up production for use in cathodes, which is the positive end of a battery and represents the bulk of its cost.

At the time, Phostech was making only about 1 metric ton (t) of LFP per year. Geoffroy mixed the precursors at a facility in Quebec and cooked the mixture in a kiln in Ontario, more than 700 km away. “Then I would put it in my car and drive home,” he says. “I would go to FedEx to ship it to customers.”

Eventually, Phostech graduated to bigger LFP factories, culminating in a 2,400 t per year plant near Montreal in 2012. Despite the progress, LFP never caught on as a chemistry for electric vehicle batteries in North America. Carmakers in the region opted instead for cathodes made with nickel and cobalt, which offer higher energy density and more range. In 2021, Johnson Matthey, which acquired the Montreal facility in 2015, put the plant up for sale.

Nickel and cobalt prices have increased substantially in the past few years, however, and nonprofit watchdogs say mining for the metals is connected to environmental problems and child labor. Nickel-based batteries are also more likely to catch fire and can’t be recharged as many times as LFP batteries.

After initially snubbing the chemistry, several big carmakers are now turning to LFP as a way to cut lithium-​ion battery costs. Ford, Rivian, and Volkswagen have all unveiled plans to use LFP in North American cars, and General Motors is interested as well. A turning point came in October 2021, when Tesla, which accounted for two-thirds of US electric car registrations last year, revealed that it would switch to LFP batteries for all its standard-range vehicles globally.

Western carmakers also want to reduce their dependence on materials from China. At the moment, China is the source of nearly all LFP batteries and the cathode powders required to make them, but several companies are trying to change that.

In October, the Israeli chemical maker ICL Group announced plans to build an LFP cathode powder factory in Missouri. The Norwegian start-up Freyr Battery and Utah-based American Battery Factory plan to make LFP cathode material in the US for their battery factories in Georgia and Arizona, respectively. Meanwhile, China’s Gotion High-Tech hopes to establish LFP cathode material production in Michigan. Other Chinese manufacturers are also weighing how to leverage their expertise in North America.

In November, the start-up Nano One Materials finalized the purchase of the old Phostech LFP plant in Montreal, promising to introduce a manufacturing process that will require less energy and produce less waste than existing methods. Geoffroy, now Nano One’s chief commercialization officer, has returned to the factory to pilot the new process and scale it up.

“I designed it, built it, managed it, left it . . . and now we’re rebuilding,” Geoffroy says. “For me, it’s a chance to do what I planned on doing with a process that I believe in.”

Born in the USA

The energy powering an electric car is released when electrons from a lithium-​ion battery’s negatively charged electrode, called the anode, flow through the motor into the battery’s positively charged cathode. To balance the electrons leaving the anode, the cathode must simultaneously accept positively charged lithium ions from an electrolyte solution.

Batteries with anodes that produce lots of electrons, and cathodes that are eager to suck them up, have a high voltage, which allows them to store more energy in a given volume. Energy density can be increased by using cathode and anode materials that can store more lithium ions.

Because nickel and cobalt cathode materials can store lots of lithium and generate a high voltage, they were used in some of the first commercial lithium-ion batteries. But even in the early days of battery development, researchers saw room for improvement.

Credit: David Giral Photography

“We wanted to reduce the cost, so we pursued cathodes based on iron, which is abundant and a cheaper metal,” says Arumugam Manthiram, a University of Texas at Austin researcher who worked with the battery trailblazer John Goodenough for decades and laid the groundwork for the class of cathodes that includes LFP.

In the mid-1990s, other researchers from Goodenough’s lab proposed using LFP, arguing that it was cheap and nontoxic. But the material wasn’t very conductive, which limited its utility. A few years later, building on the Goodenough lab’s initial discovery, scientists at Hydro-Québec and the University of Montreal solved the conductivity problem by coating LFP with carbon. Though LFP batteries still couldn’t match the energy density of nickel-based batteries, their lower cost made them appealing.

In 2003, Hydro-Québec and the University of Montreal gave Phostech the first license to manufacture LFP commercially. But investors backing North American projects were cautious, and progress was slow. “We had half a million dollars to survive for 3 years,” Geoffroy recalls. “I was paying myself by selling samples.”

Things accelerated for Phostech in 2005, when the German chemical company Süd-Chemie, which was developing a different LFP manufacturing process, bought a majority stake in Phostech. Süd-Chemie financed pilot facilities and the 2,400 t plant near Montreal, but the German firm’s hydrothermal process turned out to be more expensive than Phostech’s solid-state method. Clariant acquired Süd-Chemie in 2012 and promptly sold the LFP business to Johnson Matthey.

Geoffroy left Johnson Matthey in 2019 without seeing the plant become big enough to meaningfully supply the auto industry. “When we bought the land in 2007 there was expansion planned,” he recalls. “We never expanded.”

Other North American companies also sought to capitalize on the discovery of LFP, with limited success. In 2009, the Massachusetts Institute of Technology spinout A123 Systems raised $350 million in an initial public offering, aiming to manufacture a modified version of LFP in Michigan. But not enough carmakers were interested, and A123 went bankrupt in 2012. Most of the firm’s assets were acquired by China’s Wanxiang Group.

Made in China

LFP was invented and developed in North America, but Chinese companies were the first to place a big bet on the technology, according to Karim Zaghib, a battery scientist at Concordia University who worked for Hydro-Québec in the 1990s.

After successfully installing LFP batteries on buses ahead of the 2008 Beijing Olympics, China, impressed by the chemistry’s improved fire safety compared with nickel-based batteries, made LFP production a national project, Zaghib says. “The Chinese government and Chinese companies invested a lot in LFP.”

And the material has been a hit. In 2021, more than 40% of electric vehicles sold in China had LFP in their batteries, according to the market research firm Adamas Intelligence. “In China, small electric vehicles . . . with a range of 120 km are very popular,” says Alla Kolesnikova, head of data analytics at Adamas. “The majority of them are powered by LFP.”

Most factories in China produce LFP using a solid-state process that starts with the reaction of iron sulfate and phosphoric acid to produce iron phosphate. Usually the iron phosphate is then mixed with lithium carbonate and a source of carbon that forms the conductive coating.

Credit: Aleees

That mixture is then sent in a ceramic crucible into a kiln, where it reaches temperatures of 700–800 °C. The heat sinters the material, changing it from an amorphous mixture into the olivine structure that allows it to function as a cathode.

Between 2010 and 2016, China’s capacity to make LFP cells, or individual battery units, increased 100-fold, according to Cormac O’Laoire, managing director of the Hong Kong–based battery consulting firm Electrios Energy. By 2021, he says, Chinese companies were producing over 90% of the world’s LFP powder.

In a little over 10 years, one Chinese company, Shenzhen Dynanonic, increased its annual LFP capacity from 500 t to 265,000 t. Unlike other firms in China, Dynanonic uses a solution-based production method that resembles the hydrothermal process Süd-Chemie used in Montreal.

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Suki Zhang, Dynanonic’s account manager for overseas markets, says most of its growth has come in the past 2 years, a period when Chinese battery manufacturers, such as Contemporary Amperex Technology Co. Limited (CATL), were investing heavily in LFP. “We have so many batteries here,” she says. “The demand is a big reason why we built LFP in China.”

Chinese factories are able to make LFP cheaply, in part because the consortium of organizations that owned the relevant patents—including France’s National Center for Scientific Research, Hydro-Québec, Johnson Matthey, and the University of Montreal—agreed not to charge Chinese companies licensing fees if they sold only in China, according to an International Energy Agency report. In contrast, the Taiwan-​based LFP maker Aleees says it paid about 10% of its sales in licensing fees until recently.

The intellectual property was held more closely in other parts of the world. “That may have limited some of the development of LFP in the US and Europe,” says Anantha Desikan, ICL’s chief technology officer.

James Frith, a principal at the venture capital firm Volta Energy Technologies, points out that China has other advantages. Iron sulfate is cheap there because it’s available as a by-product of titanium dioxide production, which isn’t the case outside China, where most makers of the pigment use a different process. Frith says less-stringent environmental regulations in China can also reduce costs.

Over the past few years, the core patents behind LFP manufacturing have expired, removing a barrier for non-Chinese companies interested in producing LFP. O’Laoire says the expirations also make it easier for Chinese companies to serve markets where the patents were previously enforced.

Zhang says Dynanonic is now considering an overseas expansion, though the company hasn’t yet disclosed a specific location. Any such project would depend on the strength of battery manufacturing in other countries as well as on the rules for implementing clean energy policies like the Inflation Reduction Act, the landmark US legislation that is projected to inject $142 billion into companies making batteries or battery components in the US.

Other Chinese battery companies have already started expanding overseas. Gotion High-Tech, which has been producing LFP batteries and cathode materials in China since 2007, plans to build 100 GW h of battery cell capacity outside China over the next 3 years. In June 2022, Gotion, whose biggest shareholder is Volkswagen, announced plans for its first LFP battery factory in Europe.

Credit: Aleees

A few months later, an economic development agency in Michigan awarded Gotion’s US subsidiary grants and tax incentives to help construct a $2.4 billion plant in Big Rapids, Michigan. If built as planned, the factory will produce 150,000 t of LFP cathode material per year.

“The companies that understand how to make the product are looking to expand in other regions,” Chuck Thelen, a Gotion vice president, said at a December informational meeting hosted by Big Rapids officials.

Homecoming

Some Western firms setting up LFP cathode production in North America plan to work with partners and use established processes. Others hope to outcompete Chinese firms with new technologies.

ICL, which produces industrial phosphates and other chemicals, has been on the periphery of the LFP industry for years. It analyzed cathode materials from A123 before the company went bankrupt and began providing phosphate raw materials to LFP firms in China in 2021. In early 2022, ICL decided LFP had gained enough momentum outside China to warrant venturing into battery materials on its own.

Rising demand

In October 2022, the company received a $200 million US Department of Energy grant to build a 30,000 t per year LFP cathode material factory at its Saint Louis site, which has been producing phosphorus chemicals for more than a century. “We’ve been making phosphate salts since 1876,” says Tom Murray, ICL’s director of R&D. “Lithium iron phosphate is not very different.”

One potential difference from Chinese factories could be ICL’s starting materials. The company is evaluating using iron oxide rather than iron sulfate, which can be difficult to procure outside China. Iron oxide is more expensive, but Murray says the process produces higher-quality LFP.

At the Missouri plant, ICL will use technology from Aleees, which has been manufacturing LFP materials for nearly 2 decades. Murray says the partnership combines Aleees’s deep experience in high-quality LFP production with ICL’s expertise in large-scale chemical manufacturing. “Without them, it would be a struggle for us to jump into this and make any headway,” he says.

We’ve been making phosphate salts since 1876. Lithium iron phosphate is not very different.

Thomas Murray, director of R&D, ICL Group

Eric Chang, president of Aleees’s licensing business, says the company is eager to partner with companies like ICL because its ability to expand in Taiwan is limited by the price of land. Over the last 6 months, the company has also agreed to provide its cathode manufacturing technology to Norway’s Freyr and Australia’s Avenira.

In November, Freyr announced that it would build a $1.7 billion, 34 GW h battery factory in Georgia, and Chang says Aleees plans to help Freyr make LFP cathode materials to supply that plant.

American Battery Factory, a Utah-based company that hopes to serve the stationary energy storage market, is also partnering with an established cathode manufacturer, as yet unnamed, to set up production of LFP cathode materials in the US. The powder it makes would supply the company’s proposed cell factory in Arizona and could also be sold to other companies.

Credit: David Giral Photography

Frith says China’s cheap labor, energy, and raw materials will make it difficult for Western firms to match the country’s low cost of production, but provisions in the Inflation Reduction Act may give companies in the US enough of a boost. “Without that, I think you’re unlikely to find LFP production moving outside of China,” he says. “The economics just aren’t really there to promote it.”

While Aleees’s product costs more than LFP made in China, Chang argues that the firm is better than Chinese competitors at customizing its output for specific customers. “They lack the flexibility to fine-tune the parameters or the characteristics or properties of LFP,” he says. “They make it more like a commodity rather than a specialty chemical.”

Next generation

Some Western companies are hoping to beat Chinese competitors with new technologies that can produce high-quality LFP with a lower environmental footprint.

Nano One CEO Dan Blondal says imitating China’s solid-state process in North America could be challenging because it creates lots of sulfate waste. “China largely sweeps it under the rug,” he says. “As you try to bring that out of China to everywhere else, it’s a big impediment. It’s gonna be hellish to permit that.”

Instead, Nano One plans to use pure iron metal as an LFP precursor, eliminating the sulfate waste stream. The company also claims that this method makes the cooking step more efficient, saving energy.

Nano One is just starting to set up shop at its recently purchased Montreal factory. Temporary banners with the company’s name hang from the ceiling, but the plant’s handful of employees still wear Johnson Matthey uniforms, and bags of LFP left over from the transition bear the Johnson Matthey logo.

On the factory floor, the 100 L glass reactor Nano One currently uses for its process looks small in front of the 20 m3 stainless steel reactor Johnson Matthey used to make LFP.

Geoffroy’s task is to retrofit that reactor and the rest of the Montreal facility to work with the process. The next step is to build a new factory next door to demonstrate the technology at a larger scale. While the two plants will be substantial, they will largely serve as a blueprint for still-larger plants Nano One wants to build through joint ventures or licensing deals with bigger companies.

The Montreal plant was designed for an entirely different process, so scaling up will be a long road. Pointing to a hatch at the top of a large reactor, Geoffroy says testing the Nano One process may initially require dumping raw materials in by hand.

But Geoffroy points out that he, along with much of his team, went through this twice when they built a solid-state plant for Phostech and the hydrothermal plant for Süd-Chemie. The only difference now is that the size will be much bigger. “All the LFP made in North America commercially was really made here,” he says. “All that knowledge is there. We inherit that.”

Credit: Rio Tinto

The Massachusetts start-up 6K also wants to challenge established Chinese players with a cathode material manufacturing process that uses less energy and produces less waste.

“We have to leapfrog because we can’t compete directly with the same technology,” 6K CEO Aaron Bent says. In the US, “the workforce is more expensive, electricity is more expensive,” he says. “You’ve got to have a massively differentiated approach.”

6K’s approach involves injecting a precursor mixture containing lithium, iron, and phosphorus chemicals into a microwave plasma reactor that reaches 5,700 °C. The company says the heat and reactive ions in the plasma turn the precursors into a cathode material in a matter of seconds, eliminating the need for a kiln baking step, and most of the by-products can be recycled back into the process to reduce waste.

Like ICL, 6K received a DOE grant in October. Its research center can currently produce up to 400 t of cathode material annually, and the firm hopes to build a 10,000 t plant by 2026. 6K is also working with the US battery firm Our Next Energy to install LFP cathode production capacity at a cell factory in Michigan.

We have to leapfrog because we can’t compete directly with the same technology.

Aaron Bent, CEO, 6K

Zaghib, the Concordia University battery scientist, is skeptical that new technology is the key to building an LFP ecosystem in North America. He says the solid-state process works well, and new technologies will struggle to match its price. “If we want to accelerate LFP we need GM, Ford . . . Tesla, or some government to start putting up money,” he says.

Ford hopes to partner with CATL to build LFP battery capacity locally, but in January, Virginia governor Glenn Youngkin said he had nixed a proposal for a CATL factory in his state, according to the Virginia Mercury. For now, Ford and other carmakers will rely on batteries produced in China.

Range anxiety

The companies planning to make LFP materials in North America are betting that the lower cost of LFP-powered cars will help overcome US consumers’ anxieties about their limited range, but that’s far from a guarantee. US drivers love road trips and SUVs, which typically require large-capacity batteries.

“Our driving patterns are so different from what you see in Asia and in Europe,” says Michael Sanders, a battery industry analyst with Avicenne Energy. “I think range anxiety is going to play a much bigger role here in North America.”

There are several ways around the problem. CATL and BYD Auto, another Chinese battery maker, have engineered their LFP battery packs to be hyperefficient, increasing capacity by cramming extra cathode material into the same amount of space. Ford wants to use that technology in its LFP vehicles.

It’s also possible to use a combination of battery chemistries. Our Next Energy hopes to combine a primary LFP battery suitable for everyday use with a small lithium-metal battery that could boost a car’s range when needed. Lithium-metal batteries carry more energy than other battery chemistries, but they have yet to be commercialized, in part because they degrade after a small number of charge-discharge cycles.

Credit: Our Next Energy

Another approach is simply to make iron-based batteries better. That’s what the California start-up Mitra Chem is trying to do. The company uses machine learning to create new cathode materials that combine iron with other metals, such as manganese, to increase the energy density. “We ultimately want to get to . . . LFP 2.0, LFP 3.0, higher-energy-density products that can compete . . . with nickel,” says Vivas Kumar, cofounder and CEO of Mitra Chem.

Despite LFP’s lower energy density, many analysts, including Sanders, say technology improvements and low costs mean the battery chemistry will find a place in North America. BloombergNEF says there were no US cars powered by LFP in 2020, but it expects demand for LFP-powered cars to exceed 160 GW h by the end of the decade, representing 40% of the total demand for electric cars.

When those data were published in September 2022, only a handful of companies had announced plans to build LFP factories in the US. Several have since stepped up, and Yayoi Sekine, head of energy storage at BloombergNEF, says she thinks more will come, especially as the Inflation Reduction Act encourages battery makers to build a US supply chain.

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Geoffroy remembers when demand for LFP-powered cars was near zero in North America. About 10 years ago, when he was working at one of Phostech’s early plants, he decided to buy something made with LFP from his facility. Unfortunately, a car wasn’t an option. “I bought some small LFP batteries to power my electric trolling motor when I go fishing,” he says. “So I’m powered by LFP.”

As Nano One and other companies start building LFP factories in North America, Geoffroy is hoping for something more substantial. The moment a car built with LFP from his facility becomes available, he’s going to buy it.

Type of rechargeable battery

The lithium iron phosphate battery (LiFePO
4 battery) or LFP battery (lithium ferrophosphate) is a type of lithium-ion battery using lithium iron phosphate (LiFePO
4) as the cathode material, and a graphitic carbon electrode with a metallic backing as the anode. Because of their low cost, high safety, low toxicity, long cycle life and other factors, LFP batteries are finding a number of roles in vehicle use, utility-scale stationary applications, and backup power.[6] LFP batteries are cobalt-free.[7] As of September 2022, LFP type battery market share for EVs reached 31%, and of that, 68% was from Tesla and Chinese EV maker BYD production alone.[8] Chinese manufacturers currently hold a near monopoly of LFP battery type production.[9] With patents having started to expire in 2022 and the increased demand for cheaper EV batteries,[10] LFP type production is expected to rise further and surpass lithium nickel manganese cobalt oxides (NMC) type batteries in 2028.[11]

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The specific energy of LFP batteries is lower than that of other common lithium ion battery types such as nickel manganese cobalt (NMC) and nickel cobalt aluminum (NCA). The specific energy of CATL's LFP battery is currently 125 Watt-hours per kilogram (Wh/kg) and up to possibly 160 Wh/kg with improved packing technology. BYD's LFP battery specific energy is 150 Wh/kg. The best NMC batteries exhibit specific energy values of over 300 Wh/kg. Notably, the specific energy of Panasonic’s “2170” NCA batteries used in Tesla’s 2020 Model 3 is around 260 Wh/kg, which is 70% of its "pure chemicals" value. LFP batteries also exhibit a lower operating voltage than other lithium-ion battery types.

History

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LiFePO
4 is a natural mineral of the olivine family (triphylite). Arumugam Manthiram and John B. Goodenough first identified the polyanion class of cathode materials for lithium ion batteries.[12][13][14] LiFePO
4 was then identified as a cathode material belonging to the polyanion class for use in batteries in 1996 by Padhi et al.[15][16] Reversible extraction of lithium from LiFePO
4 and insertion of lithium into FePO
4 was demonstrated. Because of its low cost, non-toxicity, the natural abundance of iron, its excellent thermal stability, safety characteristics, electrochemical performance, and specific capacity (170 mA·h/g, or 610 C/g) it has gained considerable market acceptance.[17][18]

The chief barrier to commercialization was its intrinsically low electrical conductivity. This problem was overcome by reducing the particle size, coating the LiFePO
4 particles with conductive materials such as carbon nanotubes,[19][20] or both. This approach was developed by Michel Armand and his coworkers at Hydro-Québec and the Université de Montréal.[21] [22][23] Another approach by Yet Ming Chiang's group at MIT consisted of doping[17] LFP with cations of materials such as aluminium, niobium, and zirconium.

Negative electrodes (anode, on discharge) made of petroleum coke were used in early lithium-ion batteries; later types used natural or synthetic graphite.[24]

Specifications

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Multiple lithium iron phosphate modules are wired in series and parallel to create a 2800 Ah 52 V battery module. Total battery capacity is 145.6 kWh. Note the large, solid tinned copper busbar connecting the modules together. This busbar is rated for 700 amps DC to accommodate the high currents generated in this 48 volt DC system. Lithium iron phosphate modules, each 700 Ah, 3.25 V. Two modules are wired in parallel to create a single 3.25 V 1400 Ah battery pack with a capacity of 4.55 kWh.

• Cell voltage
  • Minimum discharge voltage = 2.0-2.8 V[25][26][27]
  • Working voltage =

    3.0 ~ 3.3 V

  • Maximum charge voltage = 3.60-3.65 V[28][26]
• Volumetric energy density = 220 Wh/L (790 kJ/L)
• Gravimetric energy density > 90 Wh/kg[29] (> 320 J/g). Up to 160 Wh/kg[1] (580 J/g).
• Cycle life from 2,700 to more than 10,000 cycles depending on conditions.[5]

Comparison with other battery types

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The LFP battery uses a lithium-ion-derived chemistry and shares many advantages and disadvantages with other lithium-ion battery chemistries. However, there are significant differences.

Resource availability

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Iron and phosphates are very common in the Earth's crust. LFP contains neither nickel[30] nor cobalt, both of which are supply-constrained and expensive. As with lithium, human rights[31] and environmental[32] concerns have been raised concerning the use of cobalt. Environmental concerns have also been raised regarding the extraction of nickel.[33]

Cost

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A 2020 report published by the Department of Energy compared the costs of large scale energy storage systems built with LFP vs NMC. It found that the cost per kWh of LFP batteries was about 6% less than NMC, and it projected that the LFP cells would last about 67% longer (more cycles). Because of differences between the cell's characteristics, the cost of some other components of the storage system would be somewhat higher for LFP, but in balance it still remains less costly per kWh than NMC.[34]

In 2020, the lowest reported LFP cell prices were $80/kWh (12.5Wh/$) with an average price of $137/kWh,[35] while in 2023 the average price had dropped to $100/kWh.[36] By early 2024, VDA-sized LFP cells were available for less than RMB 0.5/Wh ($70/kWh), while Chinese automaker Leapmotor stated it buys LFP cells at RMB 0.4/Wh ($56/kWh) and believe they could drop to RMB 0.32/Wh ($44/kWh).[37]

Better aging and cycle-life characteristics

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LFP chemistry offers a considerably longer cycle life than other lithium-ion chemistries. Under most conditions it supports more than 3,000 cycles, and under optimal conditions it supports more than 10,000 cycles. NMC batteries support about 1,000 to 2,300 cycles, depending on conditions.[5]

LFP cells experience a slower rate of capacity loss (a.k.a. greater calendar-life) than lithium-ion battery chemistries such as cobalt (LiCoO
2) or manganese spinel (LiMn
2O
4) lithium-ion polymer batteries (LiPo battery) or lithium-ion batteries.[38]

Viable alternative to lead-acid batteries

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Because of the nominal 3.2 V output, four cells can be placed in series for a nominal voltage of 12.8 V. This comes close to the nominal voltage of six-cell lead-acid batteries. Along with the good safety characteristics of LFP batteries, this makes LFP a good potential replacement for lead-acid batteries in applications such as automotive and solar applications, provided the charging systems are adapted not to damage the LFP cells through excessive charging voltages (beyond 3.6 volts DC per cell while under charge), temperature-based voltage compensation, equalisation attempts or continuous trickle charging. The LFP cells must be at least balanced initially before the pack is assembled and a protection system also needs to be implemented to ensure no cell can be discharged below a voltage of 2.5 V or severe damage will occur in most instances, due to irreversible deintercalation of LiFePO4 into FePO4.[39]

Safety

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One important advantage over other lithium-ion chemistries is thermal and chemical stability, which improves battery safety.[32][better source needed] LiFePO
4 is an intrinsically safer cathode material than LiCoO
2 and manganese dioxide spinels through omission of the cobalt, whose negative temperature coefficient of resistance can encourage thermal runaway. The P–O bond in the (PO
4)3−
ion is stronger than the Co–O bond in the (CoO
2)−
ion, so that when abused (short-circuited, overheated, etc.), the oxygen atoms are released more slowly. This stabilization of the redox energies also promotes faster ion migration.[40][better source needed]

As lithium migrates out of the cathode in a LiCoO
2 cell, the CoO
2 undergoes non-linear expansion that affects the structural integrity of the cell. The fully lithiated and unlithiated states of LiFePO
4 are structurally similar which means that LiFePO
4 cells are more structurally stable than LiCoO
2 cells.[citation needed]

No lithium remains in the cathode of a fully charged LFP cell. In a LiCoO
2 cell, approximately 50% remains. LiFePO
4 is highly resilient during oxygen loss, which typically results in an exothermic reaction in other lithium cells.[18] As a result, LiFePO
4 cells are harder to ignite in the event of mishandling (especially during charge). The LiFePO
4 battery does not decompose at high temperatures.[32]

Lower energy density

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The energy density (energy/volume) of a new LFP battery is some 14% lower than that of a new LiCoO
2 battery.[41] Since discharge rate is a percentage of battery capacity, a higher rate can be achieved by using a larger battery (more ampere hours) if low-current batteries must be used.

Uses

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Home energy storage

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Enphase pioneered LFP along with SunFusion Energy Systems LifePO4 Ultra-Safe ECHO 2.0 and Guardian E2.0 home or business energy storage batteries for reasons of cost and fire safety, although the market remains split among competing chemistries.[42] Though lower energy density compared to other lithium chemistries adds mass and volume, both may be more tolerable in a static application. In 2021, there were several suppliers to the home end user market, including SonnenBatterie and Enphase. Tesla Motors continues to use NMC batteries in its home energy storage products, but in 2021 switched to LFP for its utility-scale battery product.[43] According to EnergySage the most frequently quoted home energy storage battery brand in the U.S. is Enphase, which in 2021 surpassed Tesla Motors and LG.[44]

Vehicles

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Higher discharge rates needed for acceleration, lower weight and longer life makes this battery type ideal for forklifts, bicycles and electric cars. 12 V LiFePO4 batteries are also gaining popularity as a second (house) battery for a caravan, motor-home or boat.[45]

Tesla Motors uses LFP batteries in all standard-range Models 3 and Y made after October 2021[46] except for standard-range vehicles made with 4680 cells starting in 2022, which use an NMC chemistry.[47]

As of September 2022, LFP batteries had increased its market share of the entire EV battery market to 31%. Of those, 68% were deployed by two companies, Tesla and BYD.[48]

Lithium iron phosphate batteries officially surpassed ternary batteries in 2021 with 52% of installed capacity. Analysts estimate that its market share will exceed 60% in 2024.[49]

In February 2023, Ford announced that it will be investing $3.5 billion to build a factory in Michigan that will produce low-cost batteries for some of its electric vehicles. The project will be fully owned by a Ford subsidiary, but will use technology licensed from Chinese battery company Contemporary Amperex Technology Co., Limited (CATL).[50]

Solar-powered lighting systems

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Single "14500" (AA battery–sized) LFP cells are now used in some solar-powered landscape lighting instead of 1.2 V NiCd/NiMH.[citation needed]

LFP's higher[clarification needed] (3.2 V) working voltage lets a single cell drive an LED without circuitry to step up the voltage. Its increased tolerance to modest overcharging (compared to other Li cell types) means that LiFePO
4 can be connected to photovoltaic cells without circuitry to halt the recharge cycle.

By 2013, better solar-charged passive infrared motion detector security lamps emerged.[51] As AA-sized LFP cells have a capacity of only 600 mAh (while the lamp's bright LED may draw 60 mA), the units shine for at most 10 hours. However, if triggering is only occasional, such units may be satisfactory even charging in low sunlight, as lamp electronics ensure after-dark "idle" currents of under 1 mA.[citation needed]

Other uses

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Some electronic cigarettes use these types of batteries. Other applications include marine electrical systems[52] and propulsion, flashlights, radio-controlled models, portable motor-driven equipment, amateur radio equipment, industrial sensor systems[53] and emergency lighting.[54]

A recent modification discussed here [55] is to replace the potentially unstable separator with a more stable material. Recent discoveries found that LiFePO4 and to an extent Li-ion can degrade due to heat, when test cells were taken apart a brick red compound had formed that when analyzed suggesting that molecular breakdown of the previously believed stable separator was a common failure mode. In this case, the side reactions gradually consume Li ions trapping them in stable compounds so they can't be shuttled. Also three electrode batteries that permit external devices to detect internal shorts forming are a potential near term solution to the dendrite issue.

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