Collaborative Research: DMREF: Design of Superionic Conductors by Tuning Lattice Dynamics

NON-TECHNICAL SUMMARY

Superionic conductors are solid materials in which a subset of the atoms can flow as though they were in a liquid. These materials could be used in energy technologies such as next-generation rechargeable batteries, fuel-cells, and thermoelectric devices. However, a fundamental understanding of the atomistic mechanisms underlying the outstanding liquid-like behavior of superionic conductors remains elusive.

In the spirit of the Materials Genome Initiative (MGI), this project will develop an integrated computational and experimental framework to provide insights into the atomic-scale mechanisms controlling superionic behavior. The project will provide new quantitative understanding of the role of atomic-level disorder and crystal flexibility in the liquid-like behavior of atoms in superionic materials.

Advanced computational techniques, validated by state-of-the-art experiments, will further enable predictive modeling, accelerating the current search for new superionic materials. This research project will open new avenues for the design and discovery of efficient materials for novel energy storage and conversion technologies, and in turn, has the potential to help drive the growth of the US economy.

TECHNICAL SUMMARY

Superionic conductors are rare materials with part crystalline-part liquid character in which ions can diffuse with high mobilities. This project will rationalize atomistic processes of thermal and mass transport in superionic conductors. This will provide the critical understanding needed to accelerate the discovery and design of superionic materials for improved energy conversion technologies.

The research will investigate three design hypotheses. These are that: (1) superionic conductivity is controlled by the thermodynamic state of the mobile sublattice; (2) there is an optimal lattice softness for fast ion conductivity; and (3) superionic conductivity and low thermal conductivity are related by strong anharmonic effects and dynamic sublattice disorder.

In the spirit of the Materials Genome Initiative, these hypotheses will be tested by combining state-of-the-art computational modeling and experimental techniques to shed light on how the unusual atomic dynamics of superionic conductors enable fast ionic diffusion and control their thermal transport and thermodynamic properties. A targeted set of superionic compounds will be studied in an investigative loop between theory and experiment, combining neutron and x-ray scattering experiments, thermodynamic and transport measurements, and computer simulations of atomic dynamics using first-principles and machine-learning methods.

Additionally, this project will advance the interdisciplinary training of the early-career researchers associated with the project to afford for MGI-based workforce development. Moreover, the project will develop summer workshops, a summer exchange program between the research groups at different universities, and educational online short courses.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.