Densification and Proton Conductivity of La1-xBaxScO3-δ Electrolyte Membranes

Alyona Lesnichyova; Semyon Belyakov; Anna Stroeva; Sofia Petrova; Vasiliy Kaichev; Anton Kuzmin

doi:10.3390/membranes12111084

Densification and Proton Conductivity of La_1-xBa_xScO_3-δ Electrolyte Membranes

Membranes (Basel). 2022 Oct 31;12(11):1084. doi: 10.3390/membranes12111084.

Authors

Alyona Lesnichyova^{1

2}, Semyon Belyakov³, Anna Stroeva⁴, Sofia Petrova⁵, Vasiliy Kaichev⁶, Anton Kuzmin^{1

4}

Affiliations

¹ Laboratory of Solid-State Chemistry, Institute of Solid-State Chemistry and Mechanochemistry SB RAS, Novosibirsk 630128, Russia.
² NANOTECH Centre, Ural Federal University, Yekaterinburg 620075, Russia.
³ Laboratory of Electrochemical Materials Science, Institute of High-Temperature Electrochemistry UB RAS, Yekaterinburg 620137, Russia.
⁴ Department of Technology of Inorganic Materials and Electrochemical Production, Vyatka State University, Kirov 610000, Russia.
⁵ Laboratory of High-Entropy Alloys, Institute of Metallurgy UB RAS, Yekaterinburg 620016, Russia.
⁶ Department of Catalysis Research, Boreskov Institute of Catalysis SB RAS, Novosibirsk 630090, Russia.

Abstract

Bain La_1-xBa_xScO_3-δ impairs sintering and leads to a decrease in its ceramic density. Two approaches have been studied for obtaining dense ceramics: using a high processing temperature and the introduction of a Co₃O₄ sintering additive. An addition of only 0.5 wt% of Co₃O₄ sintering additive, despite the positive sintering effect, causes a noticeable violation of stoichiometry, with partial decomposition of the material. This can lead to the formation of cationic vacancies, which form associates with oxygen vacancies and significantly reduce the oxygen ion and proton conductivity of the materials. There is also a partial substitution of Co for Sc in La_1-xBa_xScO_3-δ, which reduces the stability of protons: it reduces the enthalpy of the hydration reaction, but increases the mobility of protons. Thus, the Co₃O₄ sintering additive causes a complex of negative effects on the conductivity of La_1-xBa_xScO_3-δ materials. Only high-temperature (1800 °C) processing with protection against Ba loss contributes to the production of dense La_1-xBa_xScO_3-δ ceramics. The chemical composition of such ceramics corresponds well to the specified one, which ensures high water uptake and, consequently, high proton conductivity.

Keywords: lanthanum scandate; proton conductivity; sintering additive.

Grants and funding

This research received no external funding.