The liquid electrolytes in the state-of-the-art lithium ion batteries contain volatile and flammable organic solvents and have raised safety concerns over the wide adoption of these batteries in large-scale applications. In contrast, solid electrolytes with high ionic conductivity and stability could potentially revolutionize the battery design and provide superior safety. This project studies the fundamental structure-property relation of a new family of solid electrolytes, namely lithium garnet oxides. A better understanding of the structure of these complex oxides will provide insight into the ionic conduction path and provide guidance in the search for other high performance materials. This project also enables a unique Materials in Batteries Around You (MBAY) outreach program to inspire the interests of K-12 students in the materials science and engineering principles involved in batteries.
TECHNICAL DETAILS: This project aims to study the crystal structure, ionic conduction, and electrochemistry of a new family of lithium garnet oxides, Li(5+x+2y)La(3)Ta(2-x-y)Zr(x)Sc(y)O(12) covering lithium content per formula from 5 to 9. The scientific goal is to find the effect of the total lithium content and lithium disorder in tetrahedral/octahedral sites on the ionic conduction mechanisms, through a combined experimental and modeling effort. The average structure and local structure is being studied by the Bragg scattering (Rietveld refinement) and diffuse scattering (pair distribution function). This total scattering investigation, along with a novel mean-field energetic modeling approach, is helping to unravel the atomistic features of lithium disorder and conduction mechanisms in these complex oxides. The electrochemical performance of these oxides is being evaluated as solid electrolytes in lithium batteries. This project provides multidisciplinary research activities for students at both the graduate and undergraduate levels and could enable the discovery of solid electrolytes essential to a renewable energy future.
