The renewable energy future, from electric vehicles to rechargeable personal devices, strongly depends on Li-ion energy storage technology. This project focuses on understanding and controlling processes in electrode materials that can allow for greater storage capacities but typically suffer from severe degradation due to changes in their solid-state structures. Most of the research, which involves both experimental and computational approaches, is designed to promote or suppress the solid-state phase change of the electrode by depositing a coating layer to impose chemical and mechanical constraints. The specific findings from this project, especially on suppressing the phase change, will enable low-cost, abundant, cobalt-free, high-capacity conversion electrodes with long cycle life for lithium-based batteries that are used in a variety of applications. The scientific advancement will stimulate the broader materials research community to explore the influence of interfacial controls on phase competition for many materials systems. Knowledge transfer is occurring through both public dissemination and direct interactions with industrial and national lab partners through the PIsâ€™ research network. Furthermore, these research activities serve as an educational platform for students at all levels and from different backgrounds to develop interdisciplinary expertise by directly experiencing both computational and experimental methods through this collaborative research.
TECHNICAL DETAILS: Pursuing both high lithium storage capacity and reversibility is a dilemma but also a crucial need as the renewable energy future, from electric vehicles to renewable power, strongly depends on Li-ion energy storage technology. This project will explore a new design principle to extend reversible intercalation reactions to higher lithium capacity by using surface modification and conformal coatings to suppress the irreversible solid-state phase transformations. Efforts at Michigan State University focus on developing a Density Functional Theory (DFT)-based multiscale modeling method to accurately predict phase evolution in the coated electrode. Efforts at University of Maryland will precisely control the surface layer with atomic layer deposition (ALD) to vary its chemistry, modulus, and thickness and perform electrochemical characterization. The collaborative efforts will determine atomistic origins of the competition between conversion and intercalation reactions during lithiation of conversion cathode materials and determine the coupled chemical-mechanical effect of the nanoscale coating layer on the competition of the two reactions. The scientific impact of this project goes beyond improved life and performance of conversion-type materials to the fundamental opportunity to understand how a materialâ€™s bulk reactions can be modulated through carefully designed interfacial control layers. Faculty from both Universities are working with students at all levels and from different backgrounds to expand educational outcomes to a broader research community.
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.