ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

An investigation and analysis of structural and electrochemical properties of highly ionic conductive La_2−xSr_xSn₂O_7−δ electrolyte for SOFC applications

Fatima Melit, Nedjemeddine Bounar, Shabana P. S. Shaikh, Manish Deshpande, and Marlu Cesar Steil

LIME Laboratory, University of Jijel, Ouled Aissa, Algeria

E-mail: fatima.melit@univ-jijel.dz

Received: 8 June 2022  Accepted: 30 December 2022

Abstract:

This study primarily focused on the investigation, synthesis and analysis of lanthanum and tin pyrochlores electrolytes for solid oxide fuel cell (SOFC) applications. Ceramic samples with diverse compositions of La_2−xSr_xSn₂O_7−δ (x = 0.05, 0.1, 0.15, 0.2, 0.25, and 0.3) were synthesized by using solid-state reaction (SSR) methods. The prepared La_2−xSr_xSn₂O_7−δ samples were characterized by using X-ray diffraction, scanning electron microscopy and electrochemical impedance spectroscopy measurements. The results were further interpreted regarding the formation of high oxygen vacancy and structural disorder in the La_2−xSr_xSn₂O_7−δ matrix. The doping of lanthanum (La³⁺) by strontium (Sr²⁺) had a beneficial and remarkable effect on the structural and electrical properties: the increase in dopant (Sr) concentration decreased the lattice parameters of the crystalline phase and enhanced the creation of oxygen vacancies, which consequently increased the ionic conductivity and decreased the activation energy. Thus, it could be understood that the studied new La_2−xSr_xSn₂O_7−δ electrolyte would be one of the potential candidates for intermediate temperature SOFC applications.

Keywords: Electrolyte; Pyrochlore; Impedance spectroscopy; Ionic conductivity; SOFC

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02659-2

Chemical Papers 77 (5) 2697–2705 (2023)