Lithium-ion batteries have come a long way from their invention in the 70s and powering small gadgets and electronics in the 90s, to electrically mobilizing present-day 60-ton trucks. Government policies and company initiatives around the globe have sped up the development rate as the race to decarbonize intensifies, to the extent that lithium-ion (li-ion in short) batteries now offer more than just fewer emissions compared to combustion engines.
Decades of testing created a variety of chemical configurations, each with their own characteristics and properties, which leads to the question: How you choose the right one for your application? Well, here we will look at the six main types of li-ion batteries and shed some light on which to use, when and why.
The six main types are:
- Lithium Nickel Manganese Cobalt (LiNixMnyCozO2 or NMC)
- Lithium Nickel Cobalt Aluminium Oxide (LiNiCoAlO2 or NCA)
- Lithium Iron Phosphate (LiFePO4 or LFP)
- Lithium Cobalt Oxide (LiCoO2 or LCO)
- Lithium Manganese Oxide (LiMn2O4 or LMO)
- Lithium Titanate (Li2TiO3 or LTO)
Each battery chemistry is judged across six metrics to determine which application it would be best suited for:
- Specific energy, which is the runtime capacity and is expressed in watt-hours per kg.
- Specific power, which is high current deliverability, expressed in watts per kg.
- Safety, in terms of temperature threshold for thermal runaway.
- Performance, which relates to capacity, voltage and resistance. It also indicates how well a battery performs across different temperatures.
- Lifespan, which is how many cycles a battery goes through before resulting in a critically low decrease in capacity.
- Cost, which is the cost of raw materials, rarity and technological complexity of putting it all together.
The different battery chemistries
NMC
Lithium nickel manganese cobalt is one of the world’s leading chemistries, providing high specific energy while offering good safety and performance levels. It is also inexpensive to produce and has a decent lifespan of around 2,000 charge cycles, giving it an excellent cost-life ratio. Its nominal voltage is 3.6V, with an energy density of 150-220Wh/kg, making it ideal for various electric vehicles.
NMC also has the lowest self-heating rate of the six configurations we’ll see in this piece, while its energy storage capacity at low weight and volume makes it an ideal option if space is tight. NMC’s chemical component quantities can be configured to include different amounts. For example, NMC111 comprises one-third each nickel, manganese and cobalt, whereas NMC 532 would be 50% nickel, 30% manganese and 20% cobalt. Other market-successful structures are NMC811 and NMC622, although with cobalt becoming more expensive and difficult to source sustainably, there’s a global push to use less cobalt in operations, or none at all where possible.
NCA
A 200-260Wh/kg energy density and a nominal voltage of 3.6V makes this combination ideal for EV powertrains, although there are safety concerns that need to be managed for this chemistry and high costs to keep in mind.
NCA-configured batteries can be found in high-performance EVs or duty-intensive off-highway electric vehicles (OHEVs) alike since they can sustain high charge rates for fast charging and deliver relatively high current for extended periods. They also have a high cycle life of over 2,000 charge cycles.
The higher nickel quantity provides the high specific energy and makes the cells less stable. Therefore, more safety measures are required to prevent battery damage and keep users safe.
LFP
Low specific energy is the only real drawback of the lithium iron phosphate battery chemistry, as it offers good metrics in everything else. A lifespan of around 10,000 charge cycles depending on state of charge and depth of discharge, high specific power and naturally stable make LFP a favourite for applications that don’t require high speeds. Furthermore, LFP batteries have a flat discharge curve, which means that as the battery depletes, performance does not suffer, unlike other li-ion battery configurations.
The LFP battery is known to be long-lasting, making it ideal for labour-intensive operations. This makes it one of the most cost-effective options on the market, with the absence of cobalt also lowering the production price. It’s widely used in various markets, including airport ground support, marine, robotics, agriculture, mining and construction.
LCO
Lithium cobalt oxide creates a battery chemistry high in specific energy, with a nominal voltage of 3.7V and an energy density of 150 to 180Wh/kg. This high specific energy but low specific power means low power loads can be delivered over an extended period, hence LCO batteries are usually found in smartphones, tablets, and laptops.
However, it’s a chemistry that scores low in safety, especially thermal stability, as high intensity will cause the battery to overheat, increasing thermal runaway risk. Portable devices now have increased computing power, so higher specific power rates must be delivered safely. So, combined with a lifespan of fewer than 1,000 charge cycles, the LCO chemistry’s days appear somewhat numbered as various industries invest in other cheaper, more efficient battery technologies.
LMO
While lithium manganese oxide scores high across most metrics, its low lifespan of around 700 charge cycles is undoubtedly a drawback. Its high nominal voltage of 3.9V, an energy density of 100-150Wh/kg, thermal stability and low self-discharge rate make it a safe option for power-intense applications. It’s cheap to produce, and manganese oxide is a non-toxic, earth-abundant metal, unlike cobalt.
LMO’s internal chemistry can be configured to suit high-load use or long-range driving as required and is also being developed to extend its charge cycle total. LMO has also been paired with the NMC chemistry for high current upon acceleration and long driving range in the mobility sphere.
LTO
Lithium titanate is also renowned for its safety and has a longer lifespan than LFP, clocking in some 15,000 charge cycles. LTO has fast charging capabilities and good specific power and performance across a vast temperature range, making it ideal for the OHEV market.
Its two major drawbacks, however, are the cost it takes to produce LTO batteries and the low specific power. It has found use in aerospace and military equipment, as well as vehicle powertrains and solar-powered applications, and having entered the market in 2008, there’s still scope to develop this battery chemistry further.
Using knowledge to power the change
In the electric mobility market, LFP and NMC chemistries are the most popular, since they offer good-to-excellent specific power and have relatively better cycle lives than the other chemistries. They perform well in low or high temperatures and are not expensive to manufacture. While these two are likely to remain the go-to chemistry for now, research is continuous across all types, so further developments are expected for each of the six li-ion battery types.
The wheels are in motion for the shift to electric drives instead of combustion engines, with plenty of benefits for the commercial sector as well as the private user. As part of our drive to power this change, we want to share our knowledge of the industry to further the electrification of everything else, so stay tuned for our next post, “Lithium-Ion Batteries At The Heart Of Electrifying Everything Else”.
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About Xerotech
Xerotech is an award-winning battery technology company solving one of our generation’s most significant challenges, industrial electrification.
Driven by a shared vision of a fully electric future, our talented team is making an impact on a global scale as Xerotech provides the first truly credible path to zero emissions and enables the electrification of machines that were previously too low-volume to be economically electrified.
Our Hibernium® battery pack platform adapts to the bespoke needs of your vehicle or application. With Hibernium®, you can choose your desired or preferred energy content, operating voltage range, physical dimensions, and even battery cell chemistry.
There are no design or engineering costs, even for one-off prototyping projects making this solution one of the only viable options for low-volume, high-diversity projects.
The electrification of heavy-duty machinery is now available to every OEM and Integrator.
