Abstract: Li-free solid-state batteries, which contain no excess Li metal initially, are considered promising next-generation energy storage systems due to their high energy density and enhanced safety. However, heterogeneous Li plating onto the current collector leads to early failure and low energy efficiency. Porous interlayers positioned between the current collector and solid electrolyte have the potential to guide uniform Li plating and improve electrochemical performance. In this configuration, both the electrochemical reduction of Li ions and mechanical deformation, which allow Li metal to flow into the porous interlayer, occur simultaneously. These complexities make understanding Li plating kinetics challenging. Factors such as stack pressure, interlayer composition, current density, and the mechanical response of the interlayer can influence Li deposition kinetics. In this talk we discuss how heterogenous plating can cause fracture in the cathode and impacts the reversible operation of li-free solid state batters. We examine a model porous Ag-C interlayer with two different Ag particle sizes and observed Li plating behavior under various stack pressures and current densities. While Ag nanoparticles in the interlayer can facilitate Li movement, they can also induce internal stress, leading to void formation that impedes Li flow. Nanostructure analysis using cryo-FIB are combined with chemomechanical modeling to uncover the mechanical interaction of interlayer during the alloying reaction between Ag and Li. When comparing the morphology of Li electrodeposits at different conditions, morphological changes correlate with the creep strain rate over Li ion flux. The electrochemical performance is determined by the morphology of Li electrodeposits rather than the Li plating current density. 

Bio: Dr. Hatzell is an associate professor at Princeton university in the Andlinger Center for Energy and Environment and department of Mechanical and aerospace engineering. Hatzell’s group primarily work on energy storage and is particularly interested at using non-equilibrium x-ray techniques to probe materials for energy and separation applications. Dr. Hatzell earned her Ph.D. in Material Science and Engineering at Drexel University, her M.S. in Mechanical Engineering from Pennsylvania State University, and her B.S./B.A. in Engineering/Economics from Swarthmore College. Hatzell’s research group works on understanding phenomena at solid|liquid, solid|gas, and solid|solid interfaces broadly work in energy storage and conversion. Hatzell is the recipient of several awards including the ORAU Powe Junior Faculty Award (2017), NSF CAREER Award (2019), ECS Toyota Young Investigator Award (2019), finalist for the BASF/Volkswagen Science in Electrochemistry Award (2019), the Nelson “Buck” Robinson award from MRS (2019), Sloan Fellowship in Chemistry (2020), and POLiS Award of Excellence for Female Researchers (2021), NASA Early Career Award (2022), ONR Young investigator award (2023) and Camille-Dreyfus Teacher-Scholar Award (2024).