Asymmetric LSCF Membranes Utilizing Commercial Powders.

Paolo Fedeli,Falk Schulze-Küppers,Stefan Baumann,Francesca Drago

doi:10.3390/ma13030614

Paolo Fedeli, Falk Schulze-Küppers + Show 2 more

Open Access

https://doi.org/10.3390/ma13030614

Copy DOI

Abstract

Powders of constant morphology and quality are indispensable for reproducible ceramic manufacturing. In this study, commercially available powders were characterized regarding their microstructural properties and screened for a reproducible membrane manufacturing process, which was done by sequential tape casting. Basing on this, the slurry composition and ratio of ingredients were systematically varied in order to obtain flat, crack-free green tapes suitable for upscaling of the manufacturing process. Debinding and sintering parameters were adjusted to obtain defect-free membranes with diminished bending. The crucial parameters are the heating ramp, sintering temperature, and dwell time. The microstructure of the asymmetric membranes was investigated, leading to a support porosity of approximately 35% and a membrane layer thickness of around 20 µm. Microstructure and oxygen flux are comparable to asymmetric La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) membranes manufactured from custom-made powder, showing an oxygen flux of > 1 mL⋅cm−2⋅min at 900 °C in air/Ar gradient.

Highlights

With a production of more than 100 million tons per year, oxygen is one of the largest chemical commodities worldwide [1]
Mixed ionic–electronic conduction was initially reported in solid oxide materials by Takahashi et al [3] and mixed ionic electronic conducting (MIEC) solid oxides were first applied for oxygen separation in the early 1980s [4,5]
An extensive investigation activity has been conducted on the composition La0.6 Sr0.4 Co0.2 Fe0.8 O3−δ (LSCF), which has been identified as model material, since it is one of the best investigated mixed ionic electronic conducting materials with a sufficiently high oxygen flux and mechanochemical stability for oxygen [7,8,9,10,11,12,13,14]

Summary

Introduction

With a production of more than 100 million tons per year, oxygen is one of the largest chemical commodities worldwide [1]. Cryogenic distillation and pressure swing adsorption have been mainly applied for the production of commercial oxygen. Such technologies require both high energy consumption and operating costs. An attracting alternative is oxygen separation from air by means of ceramic oxygen transport membranes (OTMs), thanks to the low efficiency losses compared with traditional processes [2]. OTMs are gastight structures made of mixed ionic electronic conducting (MIEC) materials, where oxygen ions transport can take place through oxygen vacancies in the crystal lattice. An extensive investigation activity has been conducted on the composition La0.6 Sr0.4 Co0.2 Fe0.8 O3−δ (LSCF), which has been identified as model material, since it is one of the best investigated mixed ionic electronic conducting materials with a sufficiently high oxygen flux and mechanochemical stability for oxygen [7,8,9,10,11,12,13,14]

Methods

Results

Conclusion