Novel concepts for next generation of Reversible Solid Oxide Cells

Abstract

Reversible Solid Oxide Cells (RSOCs) have emerged as a promising technology for energy conversion and storage. In recent years, various approaches have been employed to enhance the performance of the cells, including optimizing cell architectures, fabrication processes, and the catalytic activity of composite electrodes. A common strategy to improve electrode performance is the use of a ceramic scaffold impregnated with a catalytically active phase, maximizing the number of active sites at the triple phase boundaries (TPB). Additionally, research on the synthesis and exsolution of nanostructured perovskite oxides has gained attention, as surfaces decorated with catalytically active nanoparticles play a crucial role in improving the performance and stability of SOC electrodes. In this context, additive manufacturing is also evaluated as a key technology for creating enhanced Solid Oxide Cells by design, enabling the future incorporation of materials with greater complexity. This work explores the use of additive manufacturing in producing SOCs and introduces advanced nanocomposites for electrodes using infiltration and exsolution techniques. The integration of additive manufacturing with porous ceramic fabrication techniques offers the potential to optimize microstructures and geometries, providing an alternative to conventional electrode materials and minimizing the need of CGO barrier layers. The primary objectives of this work are to demonstrate the scalability of 3D printing technologies for large-scale RSOC manufacturing and to fabricate a porous-dense-porous (PDP) structure using 8YSZ, combined with stereolithography and Direct Ink Writing methods. This structure is then functionalized with Ag-doped La0. 8Sr0. 2MnO3 (LSAM) through in-situ infiltration. This thesis is organized into seven chapters. The first chapter presents the current energy landscape, the fundamentals of reversible solid oxide cells, and the state-of-the-art in materials and methods. Chapter II details the experimental methods, including the fabrication of large-area cells using stereolithography, ink formulation for Direct Ink Writing, electrode synthesis via exsolution and infiltration, and device assembly. Chapter III demonstrates the scalability of 3D printing for producing large-area 3YSZ electrolytes for electrolyte-supported cells, emphasizing the performance improvements enabled by additive manufacturing. Chapter IV focuses on the fabrication of large-area 8YSZ electrolytes using 3D printing techniques and their application in SOCs. Chapter V explores the optimization of SOC devices through a combination of additive manufacturing and porous ceramic fabrication techniques, highlighting the creation of a PDP structure functionalized with LSAM. Chapter VI presents the synthesis and characterization of exsolved active dopants, particularly Silver on LSAM as an oxygen electrode, and evaluates their performance through electrochemical analysis. Chapter VII concludes by summarizing the key achievements and discussing future research directions.

Date of Award	22 Nov 2024
Original language	English
Supervisor	Marc Torrell Faro (Director) & Alberto Tarancon Rubio (Director)