Collaborative Research: Fundamental understanding of interface dynamics in solid electrolyte batteries with liquid metal anode

Regents Of The University Of Michigan - Dearborn, Dearborn MI

Investigators

Abstract

Solid-state lithium-ion batteries (LIBs) present a safer alternative to their commercially available counterparts that utilize liquid electrolytes, due to the substantial safety risks associated with solvent leakage and flammability. Such batteries could even support smaller and more powerful battery packs by diminishing the necessity for extra safety features. However, despite the benefits of these highly ionic conductive solid electrolytes, achieving comparable specific capacity, rate capability, and cycle life to that of liquid electrolyte LIBs remains challenging. Research indicates a major obstacle being inadequate interfacing between solid electrolytes and solid electrodes. Contrarily, the liquid-solid interface in liquid electrolytes permits full electrode infiltration, fostering comprehensive lithium-ion transport across the surface of active material particles. To leverage the benefits of the liquid-solid interface in solid-state batteries, the research team proposes a transition from the solid-solid interface to a liquid-solid interface. This could be achieved by replacing the solid electrode with a liquid metal electrode within solid-state LIBs. During the processes of lithium-ion insertion and removal, both the electrode-electrolyte interface and the interior of the liquid metal particle experience continuous alterations due to the shift between liquid and solid states. It is essential to understand these dynamic changes to fully investigate the potential of liquid metal solid electrolyte LIBs. The objective of this project is to gain a fundamental understanding of the interface dynamics between the liquid metal anode and the solid electrolyte during lithium-ion insertion and removal processes. The project will cultivate a diverse and inclusive team, encompassing graduate students, undergraduate students, precollege students, and K-12 teachers, with special emphasis on encouraging the participation of underrepresented populations. The project aims to provide interdisciplinary training to students, bridging the gap between theoretical understanding and experimentation. In this project, the team proposes an innovative approach to study a novel solid electrolyte LIB, the first to utilize a liquid metal electrode and a solid electrolyte, forming a liquid-solid interface at room temperature. Their objective is to understand how the transition between this liquid-solid interface and the solid-solid interface occurs during lithium-ion insertion and removal processes. Insight gained from this investigation will foster the development of new techniques that incorporate liquid metal electrodes in solid electrolyte batteries. The team will utilize in situ and operando focused ion beam-scanning electron microscopy (FIB-SEM) to analyze dynamic changes in morphology and monitor the advancement of the liquid-solid reaction front in liquid metal particles during cycling processes. Furthermore, the researchers aim to investigate the influence of dopants by studying dynamic phase changes obtained through operando X-ray diffraction (XRD). To understand the development of stress and strain, along with its effect on phases and morphologies within a liquid metal particle during lithium-ion insertion and removal, numerical simulations based on a phase field model, incorporating fluid-structure interaction, electrochemical reaction, species diffusion, and interfacial effects, will be conducted. 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.