Do LFP Batteries Have a Future in EV Construction?

Electric vehicles (EVs) depend upon lithium-ion batteries to provide the necessary energy and power to produce acceptable range and performance. The most powerful lithium-ion batteries use a combination of the oxides of nickel, cobalt, and either manganese (NMC) or aluminum (NCA) as their cathodes. These nickel-based battery formulations can allow EVs to travel more than 300 miles on a charge, thanks to their high energy density—defined as the number of watt-hours (Wh) of energy that can be stored in a kilogram (kg) of battery. The cobalt included in the formulation helps to stabilize the cathode structure and allows the storage and retrieval of large numbers of lithium ions without damage to the cathode.

 

Lithium-ferro-phosphate battery. Image used courtesy of Ford Motor Company 

 

Nickel and cobalt are not inexpensive metals, and cobalt, in particular, has its own issues. More than 70 percent of the world’s cobalt is produced in the Democratic Republic of the Congo (DRC) in Africa, a country that is politically unstable and has severe human rights issues. Automakers are careful in how they source the cobalt that they use in their EVs, avoiding the artisanal and small-scale mining in the DRC that may exploit child labor. Nevertheless, finding ways to reduce or eliminate cobalt from the battery cathode is a major concern for battery suppliers and automakers. 

 

Using LFP for Cathodes

One cobalt-free battery cathode uses lithium, iron, and phosphorous to produce the lithium ferro-phosphate (LFP) battery. LFP as a cathode material was first identified in 1996 and has found applications in electric power tools, solar energy storage, and large-scale grid energy storage. Iron and phosphate are relatively inexpensive materials, and LFP cells are estimated to be between 30 and 40 percent cheaper than those made with NMC cathodes. LFP cells have a long cycle life and are stable at high temperatures They are also capable of deeper discharging than NMC cells and are considered safer due to the reduced likelihood of thermal runaway if over or undercharged or damaged.

LFP batteries in EV applications were initially resisted, primarily because an NMC battery has an energy density of 150 to 300 Wh/kg while LFP battery cells have an energy density of 90 to 160 Wh/kg. The lower energy density means that LFP batteries that weigh the same as an NMC battery will carry less energy and therefore result in a lower EV range on a charge, or to attain the same range as an NMC battery-equipped vehicle, a greater mass of LFP batteries must be carried. 

 

Lower Costs and Longer Range for EVs

Although many consumers may feel like a 300-mile range is the minimum acceptable for an EV, the average daily commute is less than 50 miles, and for many vehicles that are used primarily in cities and suburbs and rarely travel on long trips, a range of 200 miles is more than adequate. This, and the significant cost advantage of LFP batteries, has led Tesla, Ford, and carmakers in China to move some of their EVs into LFP battery systems. In fact, the Chinese company BYD holds most of the technical know-how for large-scale LFP production, and both Tesla and Ford use that company’s technology. 

 

LFP Weight and Carbon Emissions

The extra weight of LFP batteries to achieve the same range as NMC batteries has an unexpected consequence. According to Benchmark Minerals, the production of a nickel-based NCM cathode has 4 percent lower carbon dioxide emissions than does the production of an LFP cathode. Much of the carbon footprint involved in battery production depends upon the source of energy employed in the production process. However, the lower energy density of LFP also implies that more active and inactive battery materials are required for an LFP cell to reach the same energy capacity as an NMC cell, and this extra material also results in higher carbon emissions. The longer expected lifetime of an LFP cell will also play into the total emissions considerations. 

 

A comparison of emission for LFP and NCM batteries. Image used courtesy of Benchmark Minerals 

 

Ford: Yes or No to LFP?

In February of this year, Ford Motor Company announced that it would build a $3.5 billion LFP battery plant in Marshall, Michigan. The plan was for Ford to build and own the plant but to license the LFP technology from Chinese battery giant Contemporary Amperex Technology Co., Limited (CATL). Ford had indicated that it would be adding LFP batteries to its EV lineup, beginning with the Mustang Mach-E this year. LFP batteries would allow Ford to build a larger number of EVs while offering them at a lower price and, in addition, support the goal of an 8 percent margin on the sale of new electrified vehicles by 2026. 

However, Ford is pausing construction of its Marshall LFP plant. Although Ford has not indicated specific reasons for the delay, it is known that local residents have objected to the plant in their backyards, and some members of Congress have questioned the use of Chinese technology in such a critical part of the automobile industry. In addition, the United Auto Workers strike may have affected Ford’s decision.  

How the pause in construction of the Marshall plant will affect Ford’s LFP plans for the Mustang, Ford F-150 Lightning, and future EVs is as yet unclear.