Pick up at hotel

• Adrian Del Maestro (University of Tennessee, Knoxville)

Travel to IAMM.

Adrian Del Maestro - Research Meeting

• Adrian Del Maestro (University of Tennessee, Knoxville)

Room: 321

Improving Li Diffusion in Solid State Electrolytes by Neutron Irradiation Induced Vacancies: Combined Theoretical and Experimental Study

• Carlos Wexler (University of Missouri)

Room: 310 Solid state electrolytes (SSE) have the potential to enhance the performance of batteries, fuel cells and supercapacitors due to the fact that they are non-flammable, would not have the potential to leak toxic organic compounds, can perform better at higher temperatures and would suppress the growth of metal dendrites. However, most SSE’s have small ionic conductivities vs. that of their liquid counterparts. A variety of SSE’s are of interest; in this talk we focus in LiBO2 in a path to explore other (more promising) materials. LiBO2 ionic conductivity is very low (~10^-6–10^-5 S/cm), requiring improvement. Here we consider the effect of lattice vacancies in the Li-ion transport. In particular, B vacancies can be produced relatively uniformly through the sample by means of thermal neutron irradiation, e.g., through the boron neutron capture reaction ¹⁰B + ¹n → ⁷Li + ⁴He + 2.79 MeV. By means of density functional theory (DFT) calculations we show that B vacancies significantly reduce the activation energy (Em) of Li-ion transport in both monoclinic (α phase) and tetragonal (γ phase) polymorphs of LBO2 leading to a significant enhancement of the ionic conductivity (in contrast, while O vacancies lower Em in m-LBO2, they increase it in t-LBO2) [1]. Experimentally, monoclinic (α phase) polycrystalline LiBO2 powders were pressed into pellets and irradiated with thermal neutrons at the University of Missouri Research Reactor (MURR). X-ray diffraction (XRD) shows no new crystalline phases, suggesting that neutron irradiation does not significantly degrade the crystal structure. Scanning electron microscopy (SEM) and x-ray photoelectron spectroscopy (XPS) show systematic dose-dependent changes of surface microstructure and chemistry, indicating the presence of neutron-induced defects, such as B vacancies. Electrochemical impedance spectroscopy (EIS) shows a ~30% increase of the ionic conductivity of pellets irradiated 60 minutes, suggesting that thermal neutron irradiation might be a viable strategy to improve the ionic conductivity of LiBO2. [1] C. Ziemke, HM Nguyen, S. Amaya-Roncancio, J. Ghal, Y. Xing, T.W. Heitmann, and C. Wexler, Formation of lattice vacancies and their effects on lithium-ion transport in LiBO2 crystals: comparative ab initio studies, J. Mater. Chem. A 13, 3146 (2025). Funded in part by MU Materials Science and Engineering Institute Grant CD002339 and MURR. We acknowledge the computing infrastructure provided by MU Research Support Services.

Research Meeting

• Claudia Rawn (University of Tennessee)

Room: 223

Research Meeting

• Yang Zhang

Room: 257

Research Meeting

• Amber White (University of Tennessee)

Room: 325

Research Meeting

• Wonhee Ko (University of Tennessee, Knoxville)

Room: 233

Research Meeting

• Jonathan D'Emidio

Room: 271

Research Meeting

• Hanno Weitering

Room: 303

Research Meeting

Research Meeting

Research Meeting

• Hatem Barghathi

Room: 205