GÜMÜŞ AKIM TOPLAYICI MÜREKKEPLERİNDE FRİT BULUNMASININ KATI OKSİT YAKIT HÜCRESİ KATOTLARININ ELEKTROKİMYASAL PERFORMANSINA ETKİSİ

Year 2019, Volume: 7 Issue: 4, 796 - 802, 19.12.2019

Emrah Demirkal Aligül Büyükaksoy

https://doi.org/10.21923/jesd.474834

Cited By: 1

Abstract

Gümüş (Ag) içeren asıltılar (mürekkepler) orta sıcaklıklarda
çalışan katı oksit yakıt hücresi (KOYH) katotları üzerine sıklıkla akım
toplayıcı olarak uygulanırlar. Bu mürekkeplere camsı faz (frit) parçacıklarının
ısıl işlem sonrasında altlığa iyi yapışma sağlanması amacıyla eklenmesi
geleneksel olarak uygulanagelmiştir. Fakat bu parçacıkların Ag mürekkeplerine
eklenmelerinin akım toplayıcı mikroyapısı ve performansı üzerindeki etkileri net
olarak tespit edilmemiştir. Bu çalışmada gümüş mürekkeplerine frit eklenmesinin
La_0.6Sr_0.4FeO₃ (LSF) ince film katotlarının
elektrokimyasal performansına etkisi sunulmaktadır. Mikroyapısal analizler frit
etkisinin Ag akım toplayıcı katmanını yoğunlaştırdığını göstermektedir. Ag
yerine eklenen camsı faz Ag /LSF ince film katot arayüzey alanını azaltmakta ve
yüksek ohmik dirence sebep olmaktadır. Camsı faz ayrıca LSF yüzeyini
mühürlemekte, böylece yüksek polarizasyon dirençlerine yol açmaktadır. Simetrik
yarı-hücreler üzerinde gerçekleştirilen elektrokimyasal empedans spektroskopisi
ölçümleri frit içermeyen Ag mürekkepleri kullanıldığında itriya katkılı
zirkonya elektrolitin özdirenci ile örtüşen ohmik dirençler ve kabul edilebilir
katot polarizasyon dirençlerinin (örn., 700 ℃ ve
durağan hava ortamında 0.5 Ωcm²) elde
edilebildiğini göstermektedir. 

Keywords

Katı Oksit Yakıt Hücreleri, Akım Toplayıcı, Gümüş, Empedans Spektroskopisi, Katot

EFFECT OF FRIT CONTENT IN THE SILVER CURRENT COLLECTOR INKS ON THE ELECTROCHEMICAL PERFORMANCE OF SOLID OXIDE FUEL CELL CATHODES

Abstract

Silver (Ag) inks are
often used as precursors to form current collector layers on the
intermediate-temperature solid oxide fuel cell (SOFC) cathodes. It has been
common practice to add glassy phase (frit) particles into the Ag inks to
achieve good adhesion between the current collector and the cathode layers upon
firing. However, insufficient attention has been given to the effects of frit
content on the microstructure and the current collecting properties of Ag
layers. This study presents the effect of frit addition on the measured
electrochemical performance of La_0.6Sr_0.4FeO₃
(LSF) thin film cathodes. Microstructural analyses reveal that frit addition
significantly densifies the Ag current collector layer. The glassy phase
replacing Ag reduces the contact area between the Ag particles and the LSF thin
film cathode, resulting in increased ohmic resistances. The glassy phase also
seals the electrocatalytic surface of the LSF thin film, thus enhancing the
cathode polarization resistances. Electrochemical impedance spectroscopy
measurements on symmetrical half-cells reveal that ohmic resistances matching
the resistivity of the yttria stabilized zirconia electrolyte (YSZ) and
acceptable cathode polarization resistances (e.g., 0.5 Ωcm² at 700℃ in air) can be obtained when frit-free Ag current collector inks are
used. 

Keywords

Solid Oxide Fuel Cells, Current Collectors, Silver, Impedance Spectroscopy, Cathode

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