Lithium Titanium Oxide

Lithium Titanium Oxide, shortened to Lithium Titanate and abbreviated as LTO in the battery world.

An LTO battery is a modified lithium-ion battery that uses lithium titanate (Li₄Ti₅O₁₂) nanocrystals, instead of carbon, on the surface of its anode. This gives an effective area ~30x that of carbon.

The options for the cathode material are as varied.

Advantages

• High charge and discharge rates
• High cycle life – 3000 to 8000 cycles
• High stability and safety
• Wide temperature range -30°C to 60°C for charge and discharge
• Low DCIR

Disadvantages

• High half-cell voltage and low specific capacity
  • 1.55 V vs. Li/Li+ compared to 0.2 V vs. Li/Li+ for graphite
  • 180 mAh g⁻¹ compared to 370 mAh g⁻¹ for graphite
• Cell Level
  • Low nominal voltage ~2.4V
  • Low energy density ~80Wh/kg
• Higher cost / kWh

BMS Model

Schröer et al [2] show that equivalent circuit models, consisting of one series resistance representing ohmic losses and two to three RC elements, are able to predict the cells’ terminal voltage under load in a wide range of operations. They also found that with 1% SoC errors they could ignore the small hysteresis effect and temperature impact on open circuit voltage.

References

1. Liqiang Wang, Zichao Wang, Qun Ju, Wei Wang, Zhanguo Wang, Characteristic Analysis of Lithium Titanate Battery, Energy Procedia, Volume 105, 2017
2. Schröer, Philipp & van Faassen, Hedi & Nemeth, Thomas & Kuipers, Matthias & Sauer, Dirk Uwe, Challenges in Modeling High Power Lithium Titanate Oxide Cells in Battery Management Systems, Journal of Energy Storage, Volume 28, 2020
3. Florian Hall, Jonas Touzri, Sabine Wußler, Hilmi Buqa, Wolfgang G. Bessler, Experimental investigation of the thermal and cycling behavior of a lithium titanate-based lithium-ion pouch cell, Journal of Energy Storage, Volume 17, 2018

Battery Chemistry

The fundamental battery chemistry or more correctly the Electrochemistry. This is the cathode, anode and electrolyte. What are they, who makes them, where next on the roadmap, what is the latest research and what are the pros and cons of each.