Hume-Rothery Symposium on First-Principles Materials Design: Interface First-principle Method with Experiments II
Sponsored by: TMS Functional Materials Division, TMS Structural Materials Division, TMS: Alloy Phases Committee
Program Organizers: Bin Ouyang, Florida State University; Mark Asta, University of California, Berkeley; Geoffroy Hautier, Dartmouth College; Wei Xiong, University of Pittsburgh; Anton Van der Ven, University of California, Santa Barbara
Wednesday 2:00 PM
March 22, 2023
Room: Cobalt 501C
Location: Hilton
Session Chair: Raphaële Clément, University of California, Santa Barbara; Hailong Chen, Georgia Institute of Technology
2:00 PM Invited
Origin of the Invar Effect: Brent Fultz1; Stefan Lohaus1; Pedro Guzman1; 1California Institute of Technology
We found that Fe64Ni36 Invar has zero thermal expansion over modest pressures near 300K. This enabled an assessment of thermal expansion by a thermodynamic Maxwell relation, dS/dP=-dV/dT, using separate entropy contributions. Specifically, the pressure dependence of phonon entropy and magnetic entropy were obtained by nuclear resonant X-ray scattering measurements on isotopic 57Fe64Ni36 in a diamond anvil cell. The contributions to entropy from phonons and spins have opposite signs, and both increase by more than a factor of two over the pressures of Invar behavior. They have opposite signs, however, and cancel precisely during Invar behavior. At pressures above 3GPa this cancellation is lost, but consistently with the positive thermal expansion. The cancellation of the dS/dP from phonons and spins seems to be aided by a magnon-phonon interactions. This precise cancellation causes the Invar effect in Fe64Ni36. This work was supported by the National Science Foundation under Grant No. 1904714.
2:30 PM Invited
Structure Determination – From Materials Design to Characterization: Maria Chan1; 1Argonne National Laboratory
Whether to improve materials functionality or to decipher materials transformations during use, the ability to determine atomistic structure corresponding to a certain property or to a characterization signal is key. In this talk, we will discuss various approaches used to determine structure and corresponding observable properties, and data-based approaches to accelerate structure determination.
3:00 PM Invited
Design of Novel Electrode and Solid Electrolyte Materials Guided by Crystal Structure Characterization and Understanding: Hailong Chen1; 1Georgia Institute of Technology
In recent years, computational techniques, e.g., AI, machining learning, ab initio computation and high-throughput modeling, have been offering a great deal of new opportunities in materials design. On the other hand, the advances in characterization techniques are also providing a deeper and more insightful view of the crystal structure of functional materials. To reveal the structure-property relationship of functional materials and develop rational design strategies, it is important to bridge up advanced characterizations, computation, and materials design. Here we will report a couple of case studies, where the in-depth crystal structure characterization offers new understanding on the ionic diffusion mechanism in solids and leads to the successful development of a group of high-performance solid electrolyte and electrode materials, which can be used in promising next-gen all-solid-state Li-ion batteries.
3:30 PM Break
3:50 PM Invited
Understanding Key Properties of Disordered Rock-salt Li-ion Cathode Materials Based on Ab Initio Calculations and Experiments: Jinhyuk Lee1; 1McGill University
While the Li-ion battery prices have decreased about 90% in the last decade, this year saw a price increase for the first time primarily due to price swings in critical battery metals (Li, Ni, Co) used in current cathode materials with the layered structure. Disordered rock-salt (DRX) cathode materials have recently received much attention for their ability to deliver high capacity and energy density while being made with earth-abundant and inexpensive metals (e.g., Mn, Ti). In this talk, we demonstrate how combined ab initio calculations and experiments can help understand key properties (e.g., Li diffusion mechanism, redox processes, voltage) of the DRX cathodes to improve their cycling performance.