LEAPS-MPS: Machine Learning-guided Identification of Mechanically Stabilizing Solid-state Electrolytes

NON-TECHNICAL SUMMARY Lithium-ion batteries are playing an increasingly important role in our daily lives, powering devices like smartphones, tablets, and electric vehicles. Current batteries, however, have major limitations such as safety issues and the need for frequent recharging. To meet the growing demand for energy storage, longer-lasting batteries that can store more energy are needed. A promising solution is to replace the graphite used in the negative electrode of batteries with lithium metal, which has the potential to store about 10 times more energy. However, a major challenge with lithium metal is the formation of dendrites—small, branch-like structures that grow over time and can cause short circuits, leading to battery failure. This project aims to understand how to prevent dendrite formation by studying the mechanical properties of materials and identifying electrolytes with superior mechanical characteristics. The research is conducted at the University of Houston, a major Hispanic-Serving Institution, which provides a fertile ground for broadening participation from underrepresented groups. Graduate and undergraduate students will be recruited for this project and professionally trained in the new cross-disciplinary area of big data, artificial intelligence, and computational materials science, which is highly relevant to national economic and scientific advancement. TECHNICAL SUMMARY This project aims to discover solid materials with tailored mechanical properties to be used as electrolytes in all-solid-state batteries with lithium metal anode. Replacing the liquid electrolyte in commercial Li-ion batteries with solid-state electrolytes is considered the most promising approach to suppress dendrites due to the superior mechanical properties of solid materials. However, despite extensive research efforts, no solid material that can completely suppress dendrites has been successfully identified. There are several gaps in the current understanding of dendrite suppression, including (i) limited understanding of the criteria on mechanical properties, (ii) lack of tools to accurately probe the full mechanical behaviors of solid materials, and (iii) lack of a systematic approach to identifying new solid materials as candidate electrolytes. Based on recent theoretical and experimental work, the PI hypothesizes that mechanical anisotropy, characterized by the directional dependence of elastic properties, plays a significant role at the solid-solid interface between Li metal anode and a solid material, and can thus be leveraged to design solid-state electrolytes that suppress the formation of dendrites. The project embraces the principles of the Materials Genome Initiative (MGI) and establishes a unique data-driven approach for the production and analysis of anisotropic elastic properties of materials and the investigation of their effects on Li dendrite nucleation and growth. Specifically, the project will address the gaps by (i) developing uncertainty-quantified machine learning models to predict the full elastic tensors and thus anisotropic behaviors of materials and (ii) conducting high-throughput screening to identify mechanically stabilizing solid-state electrolytes. This machine learning-guided computational screening of Li-containing materials is an efficient and effective approach to identifying promising candidates for further experimental verification. 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.