Influence of Lanthanum Doping on Structural and Electrical/Electrochemical Properties of Double Perovskite Sr2CoMoO6 as Anode Materials for Intermediate-Temperature Solid Oxide Fuel Cells

Pravin Kumar; Paramananda Jena; P K Patro; R K Lenka; A S K Sinha; Prabhakar Singh; Rajendra Kumar Singh

doi:10.1021/acsami.9b03481

Influence of Lanthanum Doping on Structural and Electrical/Electrochemical Properties of Double Perovskite Sr₂CoMoO₆ as Anode Materials for Intermediate-Temperature Solid Oxide Fuel Cells

ACS Appl Mater Interfaces. 2019 Jul 10;11(27):24659-24667. doi: 10.1021/acsami.9b03481. Epub 2019 Jun 27.

Authors

Pravin Kumar¹, Paramananda Jena², P K Patro³, R K Lenka³, A S K Sinha⁴, Prabhakar Singh⁵, Rajendra Kumar Singh¹

Affiliations

¹ Department of Physics, Institute of Science , Banaras Hindu University , Varanasi 221005 , India.
² School of Material Science of Engineering and Technology, Indian Institute of Technology , Banaras Hindu University , Varanasi 221005 , India.
³ Powder Metallurgy Division, Materials Group , Bhabha Atomic Research Centre , Vashi Complex , Navi Mumbai 400703 , India.
⁴ Department of Chemical Engineering and Technology, Indian Institute of Technology , Banaras Hindu University , Varanasi 221 005 , India.
⁵ Department of Physics , Indian Institute of Technology (Banaras Hindu University) , Varanasi 221005 , India.

PMID: 31246405
DOI: 10.1021/acsami.9b03481

Abstract

Lanthanum (La³⁺)-doped double perovskites Sr₂CoMoO₆ (Sr_2-xLa_xCoMoO₆, 0.00 ≤ x ≤ 0.03) were synthesized via the citrate-nitrate autocombustion route. The Reitveld refinement analysis of X-ray diffraction reveals the tetragonal symmetry as the main phase with space group I4/m and also confirms the presence of some peaks corresponding to extra phase SrMoO₄. The SEM micrograph images reflect that grains are in irregular shape and sizes for all samples. Average grain size gradually decreases with the increase of the SrMoO₄ phase. The X-ray photoelectron spectroscopy (XPS) analysis confirms the presence of mixed valence states of Mo⁵⁺/Mo⁶⁺, Co²⁺/Co³⁺, and O-lattice/O-chemisorbed/O-physisorbed species. Coefficient of thermal expansion (CTE) analysis shows that the particular composition Sr_1.97La_0.03CoMoO₆ has the lowest CTE value among the compositions studied. The electrical conductivity of Sr₂CoMoO₆ is enhanced effectively by doping La at Sr sites. The measured area-specific resistance (ASR) for the composition Sr_1.97La_0.03CoMoO₆ (SLCM03) is found to be appreciably low, ∼0.053 Ohm cm^-2 at 800 °C. The obtained highest electrical conductivity with the lowest activation energy and low ASR value for the composition Sr_1.97La_0.03CoMoO₆ encompasses it as a promising candidate for anode material in the intermediate-temperature solid oxide fuel cell (IT-SOFC) application.

Keywords: IT-SOFC anode materials; X-ray photoelectron spectroscopy analysis; area-specific resistance; double perovskites; electrical conductivity.