Development of layered anode structures supported over Apatite-type Solid Electrolytes

P Pandis,T Kharlamova,V.N Stathopoulos,V Sadykov,M.G Skarpetis

doi:10.1051/matecconf/20164104001

Abstract

Apatite-type lanthanum silicates (ATLS) materials have attracted interest in recent literature as solid electrolytes for SOFCs. The fabrication of an ATLS based fuel cell with the state-of-art electrodes (NiO/YSZ as anode and LSCF or LSM as cathode) can show degradation after long operation hours due to Si diffusion mainly towards the anode. In this work, we report a “layer-by-layer anodic electrodes” fabrication by means of spin coating and physical spraying. The overall aim of this work is the successful fabrication of such a layered structure including suitable blocking layers towards the inhibition of Si interdiffusion from the apatite electrolyte to the anode. The results showed that the deposition of 3 layers of LFSO/GDC (3μm), NiO/GDC (4μm) and the final NiO/YSZ anode layer provided a stable half-cell, with no solid state reaction occurring among the electrodes and no Si diffusion observed towards the anode after thermal treatment at 800°C for 120h.

Highlights

Two major problems hinder the overall performance of a solid oxide fuel cells: the improper electrode layer deposition and the solid state phenomena and cation interdiffusion from sealants, pastes and even from electrolyte towards the electrodes leading to cell degradation
The first major problem mentioned is overcomed in this work by deploying techniques such as spin coating and physical spraying
From Archimedes method the dense pellets exhibited a relative density of 96%, enabling LFSO as a suitable substrate of deploying layer deposition techniques

Summary

Introduction

Two major problems hinder the overall performance of a solid oxide fuel cells: the improper electrode layer deposition and the solid state phenomena and cation interdiffusion from sealants, pastes and even from electrolyte towards the electrodes leading to cell degradation. Another issue hindering large-scale practical application of SOFCs based on the state-of-the-art YSZ electrolyte is its high operating temperature (~1000oC). The overall concept is based on the idea of the subsequent deposition of anodic layers onto dense apatite pellet by means of spin coating and physical spraying in order to provide a coherent and solid structure of anodic-based layered structured on dense apatite-type electrolyte in order to overcome the aforementioned issues.

Objectives

Results

Conclusion