Effect of scandium on the phase composition, microstructure and electrical conductivity of strontium hafnate

• Published in: International journal of hydrogen energy Vol. 48; no. 59; pp. 22649 - 22655
• Main Authors: Filatov, Nikita M., Belyakov, Semyon A., Novikova, Yulia V., Dunyushkina, Liliya A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 12.07.2023
• Subjects: Hydrogen production; Proton conduction; Sc-doped strontium hafnate; Sintering ability; Solid oxide electrolyte; Sc-doped strontium hafnate; Solid oxide electrolyte; Sintering ability; Proton conduction; Hydrogen production
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2023.02.107

Effect of Sc-doping on crystal structure, morphology and conductivity of SrHfO3 was studied for the first time. SrHf1-xScxO3-δ (x = 0–0.15) was synthesized by solid state reaction and examined using Rietveld refinement of X-ray diffraction patterns, scanning electron microscopy and four-probe DC technique. It was shown that scandium incorporates into the crystal lattice of SrHfO3 and SrHf1-xScxO3-δ crystallizes in the orthorhombic Pbnm space group. Sc-doping enhances the grain growth and sinterability, which results in increased density of ceramics. The conductivity of SrHf1-xScxO3-δ increases with increasing Sc-content, which is consistent with the common model of oxygen vacancies formation. Increase in conductivity with increasing water vapor partial pressure indicates a significant contribution of protons to charge transport. High ionic conductivity is combined with high ion transference numbers, which makes SrHf1-xScxO3-δ promising electrolytes for use in electrolysis cells producing clean hydrogen from steam and fuel cells converting chemical energy into electricity. [Display omitted] •Sc-doping enhances grain growth and improves sintering ability of SrHfO3.•Crystal structure of SrHfO3 was modelled using Rietveld refinement parameters.•Sc-doped SrHfO3 demonstrates significant protonic conductivity in wet atmosphere.•The sample with x = 0.15 has the highest conductivity among SrHf1-xScxO3-δ (x = 0–0.15).