Solid electrolytes for solid-state Li-ion batteries are stimulating considerable interest for next-generation energy storage applications. The Li 7 La 3 Zr 2 O 12 garnet-type solid electrolyte has received appreciable attention as a result of its high ionic conductivity.However, several challenges for the successful application of solid-state devices based on Li 7 La 3 Zr 2 O 12 remain, such as dendrite formation and maintaining physical contact at interfaces over many Li intercalation/extraction cycles. Here, we apply first-principles density functional theory to provide insights into the Li 7 La 3 Zr 2 O 12 particle morphology under various physical and chemical conditions. Our findings indicate Li segregation at the surfaces, suggesting Li-rich grain boundaries at typical synthesis and sintering conditions. On the basis of our results, we propose practical strategies to curb Li segregation at the Li 7 La 3 Zr 2 O 12 interfaces. This approach can be extended to other Li-ion conductors for the design of practical energy storage devices.

Solid electrolytes for all-solid-state batteries are generating remarkable research interest as a means to improve, their safety, stability and performance. Solid electrolytes are often polycrystalline and the effect that grain...

An important challenge when attempting to identify the role of microstructure on the properties of doped energy materials is to distinguish the behaviour of each grain boundary. In this paper we describe our recent work using atomistic simulations to investigate the structure, composition and oxygen transport of gadolinium doped cerium dioxide tilt grain boundaries. We find that energy minimisation can be systematically employed to screen grain boundary structures and dopant segregation. When dopants are distributed equally across grains, molecular dynamics simulations reveal oxygen vacancies reside near dopants, resulting in higher oxygen diffusivity. Once the dopants accumulate at the grain boundaries these grain boundaries become saturated with oxygen vacancies. We see fast oxygen diffusion within the grain boundary plane, although the depletion layer, as shown via the electrostatic potential appears to block transport across the grain boundary. However, this is highly dependent on the grain boundary structure as we find striking differences of the electrostatic potential and the segregation behaviour between each of interface studied.

Solid electrolytes for all-solid-state batteries are generating considerable research interest as a means to improving their safety, stability and performance. Manipulation of structural disorder has a significant impact on solid...