Session: 16-01-01: Government Agency Student Poster Competition

Paper Number: 150390

150390 - Structure-Mechanical Property Relationships of Ceramic-in-Polymer Composite Solid Electrolyte Fabricated via Zirconium/sulfur Interaction-Assisted Layer-by-Layer Approach 

Ceramic-in-Polymer composite solid electrolytes (SEs), characterized by impregnating ceramic ion-conductors within interconnected polymer networks, show great potential for meeting the high-performance requirements of All-solid-state batteries (ASSBs) due to the combined benefits of easy processibility, fast Li-ion conductivity, wide electrochemical window, and facile interfacial contact with Li metal anode, etc.  Grafting the surface of ceramics with functional ligands can further enhance Li-ion transport across the bulk material and at the extrinsic interface with electrodes. In this paper, we developed a layer-by-layer method that exploits the coordination interaction and electron transfer interaction between Zirconium (Zr) and Sulfur to fabricate rationally designed Aluminum Doped Lithium Lanthanum Zirconate Garnet-in-Poly(ethylene glycol diacrylate) (i.e., LLZO-in-PEGDA) composites. A detailed photopolymerization mechanism was proposed to elucidate the photopolymerization process initiated by Zr/Sulfur interactions in the absence of exogenous photoinitiators. The Zr/Sulfur interactions endowed precise control over the composition, homogeneity, and structure of the composites, thereby offering a platform for investigating the various intrinsic interphases within the composites. Additionally, the structure-mechanical property relationships of the ceramic-in-polymer composites were explored. In particular, the crosslinking density and mesh size of the interconnected polymer network were tuned through the molecular weight of monomers, the type of crosslinkable polymers, and the addition of other functional groups besides thiol groups, such as hydroxyl groups, during the formation of interconnected polymers. Such control of the interconnected polymer network affects both the mechanical properties and ionic conductivities of the composite SEs.  Notably, the LLZO-in-PEGDA composites facilitated by the Zr/Sulfur interactions demonstrated higher ionic conductivity and lower activation energy compared to their sulfur-free counterparts. This improvement can be attributed to changes in the polymer network, characterized by a larger mesh size, as well as the introduction of a lithophilic environment that promotes rapid Li-ion association and dissociation at various intrinsic interphases between sulfur-functionalized LLZO and other phases within the composites. As a result, the LLZO-in-PEGDA composites exhibited a high conductivity value of  5.1x10^-4 S cm^-1, exceeding the vendor-reported bulk ionic conductivity of polycrystalline LLZO. This suggests that the sulfur-containing ligands facilitate faster Li-ion transport across the intrinsic interphases between LLZO and other phases within the multi-phase composites, compared to the LLZO|LLZO interphases (i.e., grain boundaries) within polycrystalline LLZO.  In addition, the sulfur-containing composites can stabilize the interfacial resistance with Li anodes, suggesting the formation of a stable to metastable solid-electrolyte interlayer (SEI) layer with Li-anode. The mechanistic understanding of ion-transport in the LLZO-in-PEGDA composites and the elucidation of Zr/Sulfur interactions were used to identify approaches that can improve the mechanical property and the ionic conductivity simultaneously.

Presenting Author: Zhiming Qiang Kennesaw State University

Presenting Author Biography: Zhiming is a first-year graduate student at Kennesaw State University, pursuing a PhD degree in interdisciplinary engineering. He received his MS degree in Mechanical Engineering at University of Missouri-Kansas City. He is passionate about advancing technology in the fields of renewable energy and sustainable power systems and is dedicated to making a positive impact through innovative engineering solutions.

Authors:

Zhiming Qiang Kennesaw State University
Tara Joshi Kennesaw State University
Junjun Hu Kennesaw State University
Anish Sankuratri Kennesaw State University
Beibei Jiang Kennesaw State University