Computational Studies of Solid Electrolytes

Wake Forest University, Winston Salem NC

Investigators

Abstract

NONTECHNICAL SUMMARY This award supports computational research, software development, and education aimed to investigate the properties of materials for use in lithium and sodium batteries. The inspiration and motivation for this research is the societal need to preserve the resources of the planet and to find new and refine existing sustainable and efficient technologies to develop productive and healthy lifestyles. In small measure toward this goal, it is likely that this basic research effort will have a positive impact on the development of energy storage devices. In particular, recent developments in all-solid-state battery technology shows increasing promise in terms of improving the stability and efficiency of rechargeable batteries. These technological advances depend on performing basic research focused on understanding fundamental materials processes and on developing computational tools to reliably model and analyze them. Specifically, this research provides a detailed study of several materials, electrolytes, that enable lithium or sodium ions to flow between the battery electrodes. The PI aims to optimize the stability of these electrolytes, both their bulk forms and their interfaces with pure lithium or sodium electrodes, more specially, anodes. This work relies on using several public domain software packages that can be used for computation to predict the properties of materials. These software tools implement formal theories known as density functional theory and density functional perturbation theory. A component of the work is devoted to further develop and extend software tools that are widely used by the materials research community. Educating students in the field of materials research and in computational techniques is an essential component of the project. This project also includes student and faculty activities aimed to address societal needs with respect to energy efficiency and sustainability, for example assessing the recyclability of single-use batteries. TECHNICAL SUMMARY This project supports computational research and education focusing on the development of materials for energy storage, particularly all-solid-state rechargeable batteries. The work involves using and developing computational modeling tools to reliably predict and explain the detailed properties of the materials, particularly their stability and ionic conductivity during battery operations. The work focuses on solid state electrolyte materials designed to work with Li or Na anodes. Specifically, several solid-state electrolyte systems and their interfaces will be examined in order to determine their stability as a function of temperature in the harmonic phonon approximation, using density functional theory and density functional perturbation theory using the ABINIT and QUANTUM ESPRESSO codes. The study will continue work from previous grants on lithium and sodium thiophosphates and will examine new families of candidate electrolyte materials, possibly borates and boracites. The research will be carried out in collaboration with an experimentalist. The promising electrolytes will be further analyzed in terms of their ionic conductivities using first principles molecular dynamics techniques. Included in this work is the further development of the ATOMPAW code used to generate atomic datasets for use in several electronic structure codes such as ABINIT and QUANTUM ESPRESSO. For example, within the “generalized density functional” methodology, a self-consistent treatment of the so-called meta-GGA exchange-correlation functionals will be implemented in the atomic solver in order to generate atomic datasets consistent with the meta-GGA treatment. A component of the work is devoted to further develop and extend these community software tools. Educating students in the field of materials research and in computational techniques is an essential component of the project. This project also includes student and faculty activities aimed to address societal needs with respect to energy efficiency and sustainability, for example assessing the recyclability of single-use batteries. 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.