Quantitative Analysis of Solid-State Energy Devices via 3D Reconstruction using A FIB/SEM Dual Beam System

Abstract

The 3D reconstruction of solid-state energy devices, solid oxide fuel cells (SOFCs) and all-solid-state lithium ion batteries (ASSLIBs) has been widely utilized to analyze their complex and porous electrodes microstructure in three dimensions and quantify microstructural specificity. The microstructural characteristic of their electrodes which support the electrochemical reaction play an important role in determining the performance and durability of these devices. In order to meet the performance and stability demands of various applications, it is essential to understand the evolution of microstructures at the cell and electrodes level, which are considered important aspects that affect device life and performance. Focused ion beam/scanning electron microscope (FIB/SEM) dual beam system has an adequate scale and high spatial resolution to represent the microstructural characteristics of the solid-state energy device electrodes.

In this thesis, first, SOFCs electrode (Ni-YSZ anode and LSCF-GDC cathode) were quantified by the 3D reconstruction technique using FIB/SEM dual beam system. Various microstructure parameters were quantified such as volume fraction, particle size diameter, specific surface area and triple phase boundary. In particular, the electrochemically active TPB was successfully distinguished. It directly affects the electrode performance. Comparative studies were carried out by using quantified microstructural features. Second, interfacial contact area of all-solid-state lithium battery (ASSLB) electrode with solid oxide electrolytes were precisely quantified and discussed to unravel the intrinsic limitations of solid oxide electrolytes. Thus these in-depth analysis data can be used for designing materials and optimizing electrode design parameters for ASSLBs