CAREER: Explore Defect-Engineering-Facilitated Phonon Localization/Delocalization and Its Impact on Ion Diffusion in Ionic-Conducting Superlattices

About This Grant

A superlattice is a material that is formed in alternating layers to specific thicknesses. Ionic-conducting superlattices offer a novel and efficient approach to enhance the conduction of ions in devices that span a variety of technological applications, including renewable energy, sensors, and microelectronics. However, the complex interactions between structural defects, ions and heat within the superlattice present significant challenges to optimizing these materials. This project seeks to unlock the potential of ionic-conducting superlattices by decoding these intricate dynamics, thereby pushing the functional limits of various technologies. The new insights gained from this research not only will advance fundamental scientific understanding but also will significantly benefit society by improving energy storage and device efficiency. The research outcomes will be incorporated into educational programs ranging from university courses to K-12 initiatives, fostering a diverse STEM pipeline and inspiring the next generation of the science and engineering workforce. The goal of this project is to develop a comprehensive understanding of defect-facilitated phonon engineering in ionic-conducting superlattices, including localization/delocalization, and its impact on ion transport. Such understanding requires combining multiscale structural simulation with transport simulation, with spatial and temporal resolution, which has posed a long-standing challenge. In addition, the research outcome of this project seeks to bridge the gap between thermal transport and solid-state ionics—two scientific disciplines that are traditionally operated separately. This project will 1) Develop and validate a multiscale method for coupling phonon transport with ion conduction, capturing both long-range mesoscale structures and sublattice anharmonic vibrations; 2) Utilize a pre-selected list of geometric configurations to test the hypothesis of defect-induced phonon localization/delocalization; 3) Measure the relationship between mode-specific phonon excitation and ion diffusivity, testing the hypothesis of phonon localization-induced ion hop; 4) Integrate research into education through a variety of project-based activities to promote learning among peers and the general public. 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.