Event

1. While sulfur has been reported as a promising cathode material given its high capacity and energy density, practical usage of lithium-sulfur batteries is impeded by challenges such as the low electric conductivity of sulfur. As such, I fabricated micrometer length-scale solid-state batteries in the focused ion beam (FIB), and then biased and studied them using 4D-STEM entirely in-situ. Given the sensitivity of the system to air, I developed a full air-free setup to transfer samples to and from the glove box during sample preparation and characterization. Variations in the microstructure were studied by tracking the initial phases and reaction products. This work determines the structure-composition relationship in a model lithium-sulfur battery design upon biasing, allowing focus on a “single” controllable interface, which is crucial for identifying the mechanisms that alter lithium-ion transport and affect performance.

2. Conductive polymer binders moderate volume changes during electrochemical cycling and provide electronic conductivity and mechanical support for silicon-based composite anodes in lithium-ion batteries. Yet, the characterization of soft materials, using conventional S/TEM techniques, normally results in beam damage, providing essentially no structural information. As such, I characterized TEM samples of conductive polymers using in-situ and ex-situ 4D-STEM to address the structure of the polymer chains at the nanometer length-scale at different annealing conditions, overcoming the challenges associated with their characterization using conventional S/TEM techniques. Using 4D-STEM, I could discern between rotationally homogeneous and oriented lobes of low-q scattering, indicating semi-crystallinity associated with π-π stacking between the polymer chains. The orientation of the polymer chain alignment was mapped and variations in the characteristics of the polymer, undergoing a gradual microstructural transition upon annealing, were determined, and associated with enhancement in the electrochemical properties of the polymer.

Bio: Dr. Hadas Sternlicht has been working on developing bottom-up approaches to tailor material properties, by  elucidating correlations between fundamental nanometer length-scale mechanisms, microstructural evolution and  associated properties. Her research has been focusing on development and application of quantitative advanced  operando, in-situ and ex-situ scanning/ transmission electron microscopy (S/TEM), for fundamental and applied  studies on interface phenomena, solid-state batteries, conductive polymers, halide perovskites for solar-cells,  disconnections and grain boundaries, ceramic coatings and high-entropy ceramics. Her honors include the Hibbitt  Postdoctoral Research Fellowship in Engineering at Brown University (2018-2020), the Diamond GEMS Award of  the ACerS Basic Science Division (2017), the FEI Company Award for Outstanding and Original Research in  Microscopy (2016), the Inaugural UK- Israel Science Fellowship Grant (2015), and the DAAD research scholarship  (2014). Outside of lab, she acted as the elected Internal Vice Chair of the Molecular Foundry User Executive  Committee at the Lawrence Berkeley National Laboratory, a member of various ACerS committees, the 2022 chair  of the Solid-State Studies in Ceramics GRS and a lead organizer and co-organizer of various conference symposia.