These batteries generate power through the flow of lithium ions from a negative graphite anode to a positive cathode. Engineers make the cathode out of various metals to achieve longer battery life and improved driving range.
Lithium-ion batteries with nickel-cobalt cathodes are most common today. However, cost and safety concerns are making lithium-iron-phosphate batteries, or iron-phosphate batteries for short, more attractive.
Everything from Russia’s drawn-out invasion of Ukraine to environmental concerns is propelling increased iron-phosphate research. Tesla is already using LFP iron-phosphate batteries in half of its lineup, including the Tesla Model 3 EV sedan.
Here’s what you need to know about the pros and cons of these two main vectors of EV battery development.
|Nickel-Cobalt (NMC, etc.)||Iron-Phosphate (LFP)|
|Risk of Fire||Higher fire risk||Lower fire risk|
|Thermal Runaway||410° F||518° F|
|Maximum Safe Charge||80%||100%|
|Longevity||1,500-2,000 cycles||2,000+ cycles|
Nickel-Cobalt vs. Iron-Phosphate: 5 Must-Know Facts
- Both nickel-cobalt and iron-phosphate lithium-ion batteries work on the same principle but use different cathode materials.
- Nickel-cobalt was preferred for years because it provides a long-range, which is a desirable EV trait.
- Iron-phosphate is currently being used for more affordable vehicles, thanks to its lower costs.
- Nickel-cobalt is more likely to experience thermal runaway and battery fire, though both types can burn.
- Iron-phosphate batteries are being further developed into M3P batteries, which may outperform both current types.
What is a Nickel-Cobalt Battery?
Electric vehicle companies commonly use nickel-cobalt batteries in their EVs, thanks to the range these batteries provide.
Cobalt greatly increases energy density. In simple terms, batteries using cathodes including this metal go farther on a single charge, and recharge faster.
Two common cathode materials include lithium-nickel-manganese-cobalt oxide, or NMC batteries, and lithium-nickel-cobalt-aluminum oxide, or NCA batteries.
NMC batteries’ biggest advantage is high energy density. Nickel-cobalt alloys easily absorb and release lithium ions as they’re shunted back and forth between anode and cathode to release or recharge energy.
A 2020 Castrol survey revealed drivers are much more likely to buy an EV with a range of 320 miles or more. EV Automakers have an incentive to build EVs with longer ranges to attract more buyers.
Cobalt’s high energy density enables building batteries easily capable of long ranges and lightning-fast charging. It also helps reduce weight, since EVs already typically weigh thousands of pounds more than their ICE counterparts. Companies often suggest charging nickel-cobalt batteries to 70% to 80% to avoid degradation, which happens much faster at 100% charge.
What is an Iron-Phosphate Battery?
Iron-phosphate, or LFP, batteries use a lithium iron phosphate cathode to perform the same basic lithium-ion “see-saw” used to release or recharge energy.
Iron-phosphate cathodes don’t absorb the ions as efficiently as nickel-cobalt cathodes. Their energy density is lower, calling for trade-offs in construction.
An EV battery designer using LFP can choose to make less energy-dense cells, leading to slower charging and shorter EV range. Or, they can make larger, heavier cells to achieve faster charging and longer range. Increasing battery pack bulk can reduce cabin space, force design compromises, or simply make the vehicle heavier. LFP battery cells are 20% to 40% heavier than NMC batteries, depending on whether they have an aluminum or steel casing.
However, though less energy-dense, iron-phosphate batteries have multiple advantages. They remain stable when damaged or heated to high temperatures, making them less likely to catch fire in an accident.
Recycling LFP batteries is easier because the metals and minerals used in them are far less toxic than nickel-cobalt cathodes. They also potentially have a much longer useful lifespan.
Nickel-Cobalt vs. Iron-Phosphate Batteries: Key Differences
Analysts note that, while there is a lot of cobalt in the planet’s crust, extracting and processing it is difficult and expensive, CNBC reports. Suppliers offer only a little at a time, creating a bottleneck that drives up prices.
Watchdog organizations also call cobalt a “conflict mineral,” and it’s extracted in the Congo, where many rights violations occur during its extraction. Similarly, government bans on Russian nickel because of the Ukraine war may keep nickel prices rising.
Iron, on the other hand, is the most abundant mineral in the Earth’s crust. IHI Terrasun Solutions reports iron-phosphate or LFP batteries are 20% to 30% cheaper than nickel-cobalt batteries per kilowatt hour. Terrasun adds the price reduction may be only 5% to 15% when the whole EV system supporting the batteries is counted in. Be that as it may, even a minimum 5% cut is major cost saving multiplied by millions of EVs manufactured.
Cost is a major factor in Tesla’s switchover to LFP batteries for its lower-end, short-range vehicles. Elon Musk’s company, which still leads the EV sector, continues using nickel-cobalt batteries for long-range electric vehicles. Iron-phosphate batteries could help usher in a generation of more affordable EVs for everyday drivers.
Nickel-cobalt batteries still offer better energy density than iron-phosphate batteries pound for pound. The more a battery weighs and the more volume it occupies, the less room for anything else there is in an EV. A larger, heavier battery means less space and legroom in the interior, in some cases. Nickel-cobalt batteries offer long range and faster recharging compared to their LFP battery rivals.
However, Tesla is currently spearheading the use of LMFP batteries, a more advanced iron-phosphate battery using manganese. InsideEVs reports these batteries are nearly as cheap as LFP batteries but boost range 15% to 20%. These cathode advances could reduce the energy density gap, making iron-phosphate more viable for long-range electric vehicles.
Researchers are developing M3P batteries using LFP battery technology as a springboard. The new battery type substitutes zinc, magnesium, and aluminum in place of the iron. Scientists believe this may create an EV battery with a 435 mile range while remaining cheaper than nickel-cobalt. Tesla might roll out M3P-powered EVs in some markets by 2023.
All lithium-ion batteries can burn with great intensity when damaged in an accident or simply overloaded during recharge. Fires are statistically extremely rare but make the headlines as a result of how hard they are to extinguish.
However, thermal runaway temperature differs between the different battery architectures. Thermal runaway leading to battery ignition happens when battery temperature rises above a certain threshold. According to Battery University data, a typical nickel-cobalt NMC battery’s thermal runaway occurs at 410° F. On the other hand, LFP iron-phosphate batteries experience thermal runaway at 518° F.
Furthermore, iron-phosphate batteries remain stable at 100% charge, but nickel-cobalt batteries can potentially heat up to the point of thermal runaway. Many designers and scientists think charging a nickel-cobalt battery to 80% and stopping there is the safer option. This factor somewhat offsets the higher energy density of nickel-cobalt. Overall, iron-phosphate LFP batteries, and their M3P battery offshoots, are safer.
Research suggests LFP batteries potentially last much longer than their NMC counterparts.
Sandia National Laboratories researchers experimented in 2020 and found iron-phosphate batteries often lasted 3,000 to 4,000 cycles. After this, the batteries lost their ability to hold more than 80% of their original charge. Nickel-cobalt batteries only took 1,000 to 2,000 cycles to reach similar degradation.
The data isn’t quite as cut and dry as it might look at first glance. LFP iron-phosphate lifespan in terms of years won’t be double that of nickel-cobalt because the batteries hold less charge. This means more frequent “cycles” (discharge and recharge) in a given length of time. Nevertheless, scientists believe LFP batteries have greater overall longevity.
Nickel-cobalt batteries outshine iron-phosphate when it comes to cold weather charging and operation.
While LFP iron-phosphate batteries work fine in hot temperatures, where NMC batteries may falter, NMC is much more cold resistant.
Back in 2020, Chinese Tesla owners with new LFP battery Model 3s reported their iron-phosphate powered EVs took much longer to charge in the cold. Charging to 100% became impossible in many cases, Torque News reports. Drivers also said actual range was far below the claimed range.
Some internet articles say dropping to freezing (32° F) cuts iron-phosphate LFP battery range by 10% to 20%. At bitter temperatures of -4° F, the range seemingly falls by 40%. While these temperatures are West Coast, South, or Southwest rarities, they’re not uncommon in the Plains states in winter.
History of Nickel-Cobalt Batteries
All lithium-ion batteries, including both nickel-cobalt and iron-phosphate, have a common origin. British researcher, Michael Stanley Whittingham, developed the first rechargeable battery of this kind in the 1970s. Many later scientists made further improvements through the 1970s, 1980s, and 1990s.
Five scientists announced the invention of an NMC cathode in 1998 at Boston’s 194th Meeting of the Electrochemical Society. Multinational German chemical company, BASF SE, started large-scale commercial manufacture in 2011.
History of Iron-Phosphate Batteries
The same scientific research led to the development of LFP iron-phosphate batteries. While scientists knew about iron-phosphate cathodes for decades, they initially couldn’t figure out how to overcome its low conductivity.
French researcher, Michel Armand, working with long-time American lithium-ion battery developer, John Goodenough, found a solution in 2003. Armand and Goodenough discovered using smaller iron and phosphate particles helped. Coating the particles in carbon nanotubes to boost the flow of electric current through them made LFP battery cathodes practical. Researchers continue to work on the batteries to this day.
Nickel-Cobalt vs. Iron-Phosphate Batteries: Which is Better?
Nickel-cobalt NMC and NCA batteries offer long-range and fast charging, both attractive features for EV buyers. Iron-phosphate batteries are generally shorter range with less energy density. However, they’re also safer and longer lasting.
With Tesla at the helm, they are also serving as the research basis for new M3P batteries. Researchers make the M3P batteries nearly as safely and cheaply as LFP, but with a 400+ mile range.
Which battery is better depends on the owner’s location and intended use.
Nickel-cobalt batteries work better in cold climates, charging faster and maintaining most of their range. They are also good for people who need a long-range EV capable of very fast charging. Iron-phosphate batteries may be better for drivers in warm climates who don’t need extended range. For these EV owners, better safety, greater battery lifespan, and a possibly more affordable vehicle could be the superior option.