We are pleased to announce the publication of our new paper on lithium diffusion within lithium lanthanum titanate:

• E.E. Jay, M.J.D Rushton, A. Chroneos, R.W. Grimes and J.A. Kilner, “Genetics of superionic conductivity in lithium lanthanum titanates”, Physical Chemistry Chemical Physics, (2014). doi:10.1039/C4CP04834B

Lithium lanthanum titanate (LLTO) is a material that shows high lithium diffusivity even at room temperature, this makes it of considerable interest for battery applications. In the present paper we set out to try and understand how the arrangement of lanthanum atoms within this material leads to LLTO’s beneficial properties. This was achieved by using a genetic algorithm to search for configurations with particularly high diffusivities. These were then examined to see what could be gleaned from their structure in order to unlock the key to LLTO’s beneficial properties. The paper can be found here.

Abstract

The self-diffusion of ions is a fundamental mass transport process in solids and has a profound impact on the performance of electrochemical devices such as the solid oxide fuel cell, batteries and electrolysers. The perovskite system lithium lanthanum titanate, La_2/3−xLi_3xTiO₃ (LLTO) has been the subject of much academic interest as it displays very high lattice conductivity for a solid state Li conductor; making it a material of great technological interest for deployment in safe durable mobile power applications. However, so far, a clear picture of the structural features that lead to efficient ion diffusion pathways in LLTO, has not been fully developed. In this work we show that a genetic algorithm in conjunction with molecular dynamics can be employed to elucidate diffusion mechanisms in systems such as LLTO. Based on our simulations we provide evidence that there is a three-dimensional percolated network of Li diffusion pathways. The present approach not only reproduces experimental ionic conductivity results but the method also promises straightforward investigation and optimisation of the properties relating to superionic conductivity in materials such as LLTO. Furthermore, this method could be used to provide insights into related materials with structural disorder.