The Department of Chemical and Biological Engineering presents a talk with guest speaker Sanja Tepavcevic, a materials scientist at Argonne National Laboratory, who will present “LLTO Scaffold-Based Composite Polymer Electrolyte for Solid-State Li-ion Batteries.” This talk will take place on Wednesday, October 29, from 3:15–4:30 p.m. in room 131 of Perlstein Hall.

Abstract

We designed a novel composite polymer electrolyte (CPE) by combining interconnected Li0.5La0.5TiO3 (LLTO) nanofiber scaffold1 with in-situ polymerization and crosslinking of poly -ethylene glycol (xPEG). LLTO nanofiber scaffolds were prepared by electrospinning and subsequent thermal annealing. The mixture of PEG monomers and crosslinker was drop-casted on LLTO nanofiber scaffold to prepare self-standing LLTOxPEG electrolyte by thermal annealing. Arrhenius plots of the effective conductivity of the composites with different volume fractions of the LLTO scaffold we prepared. It is evident that with increasing volume fraction of Li+-conducting LLTO fibers, the conductivity of the composite increases. LLTOxPEG-65 achieved highest ionic conductivity of 5 × 10-4 S/cm at RT, electronic conductivity at 6-7 × 10-9 S/cm with critical current density of 0.5 mA/cm2. The low activation energy of ~0.2 eV was observed in LLTOxPEG-65, compared to 0.44eV for the LLTOxPEG-90 and pristine xPEG which was in an excellent agreement with ab-initio calculations for bulk Li -transport in crystalline LLTO. Furthermore, mesoscale level computational analysis supports the possibility of ion transport through the LLTO scaffold as long as the charge transfer resistance between the polymer and the ceramics is less than a certain threshold.

Biography

Sanja Tepavcevic is a materials scientist at Argonne National Laboratory specializing in solid-state batteries and long-duration energy storage. Her solid-state work integrates fundamental interfacial science with manufacturability, focusing on composite and thin-film electrolytes and integrated interface design for lithium-metal systems. She investigates interfacial Li-ion transport, critical current density and coulombic efficiency in LLZO-based composite polymer electrolytes, dopant-dependent stability of lithium/garnet interfaces, and how to mitigate soft-shorts and advance multilayer composite architectures for EV batteries and solid-state Li–air systems for aviation. She also leads scale-up efforts via scalable synthesis, processing, and analysis of solid-state batteries in close collaboration with industry and international partners. Complementing these advances, she contributes to long-duration storage through zinc-based aqueous electrolyte research and to community road mapping with technical reports for Storage Innovations 2030 initiative. Her intellectual property is spanning from solid-state nanofiber polymer multilayer composite electrolytes and cells, thin-film metal/oxide anodes, nanofiber polymer composite cathodes, and interface designs that enable high current-density cycling, as well as to an aqueous manganese-ion battery and high-capacity electrode materials for durable, grid-relevant storage.