EFFECT OF SR CONTENT ON THE MICROSTRUCTURE DEVELOPMENT AND ELECTROCHEMICAL PERFORMANCE OF LA1-XSRXMNO3 FILMS

Öz

Strontium doped lanthanum manganite (La1-xSrxMnO3 -LSM) is the conventionally used oxygen reduction electrocatalyst in solid oxide fuel cell cathodes. In recent years, Sr-segregation at the LSM surface has been shown to occur and limit oxygen reduction performance. Therefore, the effect of Sr-doping on the microstructure development and performance of liquid precursor-derived LSM film electrodes with different Sr-contents was investigated in this study. It was found that as Sr content increased, LSM structure became amorphous, which is beneficial for the electrochemical performance. Despite this fact, the undoped LaMnO3 film performed better in comparison to heavily Sr-doped LSM, likely because of Sr-segregation at the Sr-doped electrode surface. These results suggested that trying to avoid Sr doping in LaMnO3 electrodes may be a good strategy if its microstructural instability could be addressed, to achieve high performance solid oxide fuel cell cathodes.

Anahtar Kelimeler

• Thin films
• Polymeric precursors
• Perovskite cathode
• Strontium segregation
• Electrochemical performance

STRONSİYUM KATKISININ LA1-XSRXMNO3 FİLMLERİNİN MİKROYAPI GELİŞİMİ VE ELEKTROKİMYASAL PERFORMANSI ÜZERİNE ETKİSİ

Öz

Stronsiyum katkılı lantanyum manganez oksit, katı oksit yakıt hücresi katotlarında geleneksel olarak kullanılan oksijen indirgenme elektrokatalizörüdür. Fakat, lantanyum ile boyut farkı ve yüzeydeki oksijen boşluklarının elektrostatik çekimi nedeniyle LSM’in yüzeyinde stronsiyum birikmesi yalıtkan SrO fazının fazının oluşumuna ve performans kaybına neden olur. Bu nedenle ABO3 tipi elektrokatalizörlerin A bölgesindeki stronsiyum katkısının gerekliliği yeniden değerlendirilmelidir. Bu amaçla, LSM elektrokatalizörlerinde stronsiyum katkısının gerekliliği, itriyum katkılı zirkonyum oksit elektrolitleri üzerinde biriktirilen polimerik LSM öncüsünden türetilmiş ince filmler üzerinde yeniden değerlendirildi. Sr içeriği arttıkça kristallik ve dolayısıyla elektrokimyasal performans düştü. Bu sonuç, stronsiyum içermeyen LSM’e sahip nanokompozit elektrotlar üretilebilirse, yüksek performans için stronsiyum katkısının gerekli olmayabileceğini gösterdi.

Anahtar Kelimeler

• İnce filmler
• Polimerik öncüller
• Perovskit katot
• Stronsiyum segregasyonu
• Elektrokimyasal performans.

Kaynakça

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