Effect of doping and crystallite size on the electrochemical performance of Li4Ti5O12

Abstract

Defect spinel phase lithium titanate (Li4Ti5O12) has been suggested as a promising negative electrode material for next generation lithium ion batteries. Flame spray pyrolysis has been shown to be a viable fast, one-step process for synthesis of nanoparticulate Li4Ti5O12. However, due to the rapid quenching that is integral to the process the crystallite size remain very small and non-uniform.

To overcome this shortcoming a vertical flow tube furnace was used to increase the high-temperature residence time. This resulted in an increase in the crystallite size and crystallinity of the product. As a result of this increase the electrochemical performance of the Li4Ti5O12 was markedly improved.

Furthermore, silver doping of the Li4Ti5O12 material can be carried out simultaneously with its synthesis in the FSP process. The resulting nanosized silver particles on the surface of the Li4Ti5O12 particles further improve the electrochemical performance during high current operations.

The specific capacities of these high-temperature synthesised pure and silver-doped Li4Ti5O12 nanoparticles were found to increase by up to 6% and 19%, respectively, compared to a commercial reference. Thus the technique provides a simple method for synthesising superior quality Li4Ti5O12 for battery applications.