(166w) Flame Spray Pyrolyzed Lithium Titanate (Li4Ti5O12) As Promising Anode Material for Lithium-Ion Batteries

Spinel-structured lithium titanate (Li₄Ti₅O₁₂, LTO) is a one of the most attractive anode materials for next generation of lithium-ion batteries, due to its excellent stability, zero volume change during charge/discharge cycling and safe performance [1]. However, its size is crucial for optimized electrochemical performance.

In this regard, here, we synthesize LTO nanoparticles of different sizes (8-21 nm) by tuning flame spray pyrolysis (FSP) operating conditions. FSP is an attractive process for the controlled one-step synthesis of functional multicomponent oxides from low cost precursors and permits fine tuning of the nanoparticle properties by varying processing conditions [2]. Larger primary particles are synthesized by increasing precursor concentration in the flame which is attributed to longer particle residence time at high temperatures. As-synthesized LTO nanoparticles are used as active materials for the fabrication of working electrodes for lithium-ion battery half-cells. For comparison, LTO is also made by Pechini method and both FSP- and Pechini- made samples are compared with a commercial LTO powder in terms of their electrochemical properties. To evaluate their electrochemical performance, galvanostatic charge-discharge, rate performance and cycling voltammetry experiments are performed.

FSP made LTO of 18 nm shows the best electrochemical performance with almost 100% capacity retention after 500 charge/discharge cycles, whereas the smallest particle (8 nm) has a capacity loss more than 60%. Particle size < 16 nm leads to less efficient use of the intercalation sites due to higher ratio of surface to bulk atoms and to stress caused by the higher curvature at the crystallite surface. Tuning the particle size by optimization of flame spray conditions leads to formation of particles with specific capacity close to the theoretical value for LTO (175 mAh/g) which indicates maximum utilization of the active material per charging/discharging cycle.

References

1. Sun X., Radovanovic P., Cui B., Advances in spinel Li₄Ti₅O₁₂ anode materials for lithium-ion batteries. New Journal of Chemistry 2015;29:38-63.
2. Tsikourkitoudi V., Karlsson J., Merkl P., Loh E., Henriques-Normark B., Sotiriou G.A., Flame-made calcium phosphate nanoparticles with high drug loading for delivery of biologics. Molecules 2020;25:1747.