Samarium and Yttrium Codoped BaCeO₃ Proton Conductor with Improved Sinterability and Higher Electrical Conductivity

Abstract

Acceptor-doped barium cerate is considered as one of the state-of-the-art high temperature proton conductors (HTPCs), and the proton conductivity of such HTPCs is heavily dependent on the dopant. In this work, a codoping strategy is employed to improve the electrical conductivity and sinterability of BaCeO3-based HTPC. BaCe0.8Sm(x)Y(0.2-x)O(3-δ) (0 ≤ x ≤ 0.2) powders are synthesized by a typical citrate-nitrate combustion method. The XRD and Raman spectra reveal all the compounds have an orthorhombic perovskite structure. The effects of Sm and/or Y doping on the sinterability and electrical conductivity under different atmospheres are carefully investigated. The SEM results of the sintered BaCe0.8Sm(x)Y(0.2-x)O(3-δ) pellets indicate a significant sintering enhancement with increasing Sm concentration. BaCe0.8Sm0.1Y0.1O(3-δ) exhibits the highest electrical conductivity in hydrogen among the BaCe0.8Sm(x)Y(0.2-x)O(3-δ) pellets. Anode-supported BaCe0.8Sm0.1Y0.1O(3-δ) electrolyte membranes are also fabricated via a drop-coating process, and the corresponding single cell exhibits desirable power performance and durability at low temperatures. The results demonstrate that BaCe0.8Sm0.1Y0.1O(3-δ) is a promising proton conductor with high conductivity and sufficient sinterability for proton-conducting solid oxide fuel cells operating at reduced temperatures.

An Easily Sintered, Chemically Stable, Barium Zirconate‐Based Proton Conductor for High‐Performance Proton‐Conducting Solid Oxide Fuel Cells

“…Due to the high conductivity and good sintering activity, acceptor‐doped BaCeO 3 oxides have been widely used as electrolytes for SOFCs, and significant progress on optimization of electrolytes, electrode materials and fabrication techniques were achieved . However, under CO 2 or water vapor‐containing atmospheres, BaCeO 3 ‐based oxides exhibit poor chemical stability, which precludes their use in practical applications since water vapor is present in the electrode/electrolyte interface during fuel cell operation and the cathode side is exposed in CO 2 ‐containing air.…”

Structural, morphological and electrical studies of BaCe0.8Y0.2O3-δ synthesized by solution combustion method

“…However, the perovskite oxides (ABO 3 ) such as SrCeO 3 , BaCeO 3 , and BaZrO 3 have almost pure high proton conductivity. Among these, BaCeO 3 has been studied extensively as protonic solid electrolytes due to low activation energy and high proton conductivity [4] and has been used in different electrochemical devices such as hydrogen sensor, hydrogen pumps, and solid oxide fuel cells [5][6][7]. It is typically doped with trivalent cations like Y 3+ , In 3+ , Gd 3+ , Sm 3+ , and so on to replace Ce, which consequently produces oxygen vacancies to maintain electrical neutrality.…”

STRUCTURAL, DIELECTRIC AND A.C. CONDUCTIVITY STUDIES OF BaCe0.65 Zr0.2Y0.15O3-δ SOLID OXIDE FUEL CELL ELECTROLYTE BY CITRATE EDTA COMPLEXING SOL-GEL PROCESS.

“…The impedance spectra measured in dry air from room temperature to 500°C in is shown in the Fig 5.Theoritically the spectra composes of three arcs at low, medium and high frequencies corresponding to the response of electrode, grain boundary and the bulk respectively [23][24][25] in the Nyquist plots (Z' vs. Z").The semi circular pattern represents the electrical process taking place that can be expressed in an electrical circuit with a parallel combination of resistive and capacitive elements. In the Nyquist plots of the present work, the high frequency semi circle related to bulk response could not be observed due to the instrumental limitations of the experimental range.…”