Lithium titanate batteries are used in some Japanese-only versions of Mitsubishi’s i-MiEV electric vehicle, as well as Honda’s EV-Neo electric bike and Fit EV. Let us understand the lithium titanate battery in brief and how it can be the Brahmastra of lithium-ion batteries.
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What is Lithium Titanium (LTO) Battery?
LTO stands for Lithium Titanium Oxide or Lithium Titanate. It is an anode used in Lithium-ion batteries. Traditional Lithium-ion batteries use graphite (natural or artificial) anode along with cathodes such as LCO (Lithium Cobalt Oxide), NMC (Lithium Nickel Manganese Cobalt Oxide), NCA (Lithium Nickel Cobalt Aluminium Oxide), LFP (Lithium Iron Phosphate), etc.
Its operating voltage is on the lower side, with a window from 1.5V to 2.8V (2.3V nominal) when it uses NMC as a cathode.
On the other hand, graphite anode with NMC cathode has an operating voltage from 2.75V to 4.2V. Using an LTO anode with an LFP cathode can bring down the nominal voltage further to less than 2.0V (about 1.9V). Some companies even consider using LMO (Lithium Manganese Oxide) cathode with LTO anode.
LTO batteries have lower operating voltage because LTO anode has a high operating voltage of close to 1.5 V vs Li/Li+, which is much higher than that of graphite anodes.
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LTO Battery Advantage and Its Disadvantage?
LTO anode provides a surface area of around 100 sq.m/g, which is much higher than the 3 sq.m/g provided by graphite anode. This property of LTO allows the electrons to enter and leave quickly.
What are its advantages?
Below are the some of top advantages of lithium-titanate-oxide (LTO) batteries
- Fast charging: It can charge as fast as 10C (theoretically up to 100C), practically meaning 6 minutes to charge the battery from 0% to 80%. After 80% charge, CV mode kicks in, which reduces the speed of charging. Most of the other chemistry Lithium-ion batteries tend to max out at around a 1C rate of charging.
- Fast Discharging (High Power Discharge): LTO can discharge as much as 10C rate. It can power applications that need high power for a short period of time. For example, it would be an ideal fit for UPS for data centers, where the backup requirement time is very low every cycle.
- Wide Operating Temperatures: LTO batteries have proven to operate at temperatures ranging between -40°C to 60°C. It can even operate at a further wider range of temperatures. Unlike other chemistries of Lithium-ion batteries, which face serious irreversible capacity fade after 45°C, LTO batteries have a much slower irreversible capacity fade even when operating above 45°C.
- Safety: LTO batteries do not catch fire (like in LCO, NMC, and NCA batteries) and do not release smoke (like in LFP batteries) when damaged.
- Cycle Life: LTO batteries are advertised with the capability to have over 40,000 cycles at a 1C rate of charge and 1C rate of discharge. The cycle life tends to come down when charging and discharging at higher than 1 C rates. Its calendar aging life is expected to be 30 years, which paves the way for the second life usage of LTO batteries.
What are its disadvantages?
Gravimetric Energy Density (Specific Energy): The discharge capacity of LTO is 175mAh/g at a 0.1C rate compared to graphite which has a discharge capacity of more than 350mAh/g at a 0.1C rate. The amount of anode active material loading tends to be more and this increases the overall weight of the cell. The gravimetric energy density is more than Lead Acid batteries but lower than LFP batteries that use graphite anode.
What are the challenges for LTO batteries?
The cost of LTO batteries is a limiting factor when it comes to acceptance by the market. It is so expensive that it is not possible to compare it with traditional NMC and LFP batteries sold in the market.
The price and weight of the battery being higher are some of the reasons why LTO battery manufacturers have not expanded their production capacity as much as other chemistries of Lithium-ion batteries.
Where about its adoption?
One of the ways it has taken off in some countries for EV (electric vehicles) applications is to reuse the LTO battery multiple times a day. Since its charging time is low and its cycle life is very high, charging multiple times a day makes a good use case scenario for LTO batteries.
This use case scenario can take care of the heavy weight of LTO batteries when a smaller capacity (in kWh) of LTO battery is used for a shorter period of time.
In the case of ESS, if the demand for power backup is multiple times in a day, then its use becomes logical. If it’s being used once a day, its potential for high cycle life will go unused due to calendar aging limitations.
Lithium Titanium (LTO) Battery Manufacturer globally?
Companies such as Yinlong, Microvast, Altairnano, and Toshiba have deployed a lot of LTO batteries across the globe and their performance has been up to expectations so far.
list of manufacturers of LTO Batteries Globally:
|Samsung (uses in S pen)
|Seiko (uses in Watch)
LTO battery manufacturers in India
Log9 Materials is an Indian nanotechnology company, headquartered in Bangalore, India’s first and only company engaged in the manufacturing of Indigence Cells in India. And the company is soon launching its own tropicalized-ion battery (TiB) backed by lithium Ferro-phosphate (LFP) and lithium-titanium-oxide (LTO) battery chemistry.
Log9 Materials works in the areas of sustainable energy and filtration. With 16 patents around graphene,
The company has developed aluminum fuel cells for both mobility and stationary energy applications.
What is the future of lithium-titanium-oxide (LTO)?
Using cathodes that have higher discharge capacity (mAh/g) or have higher overvoltage limits can further improve the gravimetric and volumetric energy density of LTO batteries.
A suggestion can be to try an NCA cathode, which has one of the highest discharge capacities (mAh/g) or try an LNMO cathode that has the potential to charge above 4.7V. But LNMO cathode utilization has a challenge in terms of finding a stable electrolyte that can support charging to such high voltages.
There is a lot of research going on around this and a viable solution for this is expected soon for mass production.