Search

A new type of anode structure, composed of a group of La 0.75 Sr 0.25 Cr 0.5 Mn 0.5 O 3- δ -Ce 0.8 Sm 0.2 O 1.9 (LSCM-SDC) compositionally graded anode functional layers (CGAFL) and a porous SDC interlayer adjacent to the electrolyte, was fabricated by screen printing method for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The results of electrochemical impedance spectroscopy (EIS) show that the polarization resistance decreased from 3.49 Ω cm 2 to 1.85 Ω cm 2 at 800 °C in H 2 after introducing CGAFL. In addition, the polarization resistance further decreased to 0.30 Ω cm 2 when the CGAFL combined with the SDC interlayer, demonstrating a reduction by factors of 11.6 and 6.2, respectively, compared with the non-graded cell and the CGAFL cell without the SDC interlayer. The single cell displayed that the CGAFL combined with the SDC interlayer increased the maximum power density by factors of 2.9 and 2.1, respectively, at 800 °C. These results indicated that the CGAFL combined with the SDC interlayer may be a potential electrode structure for design optimization. [ABSTRACT FROM AUTHOR]

Composite anodes of La0.75Sr0.25Cr0.5Mn0.5O3−δ –Ce0.8Sm0.2O1.9 (LSCM–SDC) were prepared and investigated as anode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs) with YSZ electrolyte. Results showed that the addition of SDC significantly enhanced the electrochemical performance of LSCM anode. The anode containing 40 wt.% SDC demonstrated optimal performance. The polarization resistance and anodic overpotential (at a current density of 0.05 A cm−2) of this anode were 0.95 Ω cm2 and 0.12 V in H2 at 800 °C, respectively, whereas those of pure LSCM anode were 3.66 Ω cm2 and 0.38 V, respectively. The electrochemical performance of the LSCM–40SDC composite anode was further improved when a thin SDC interlayer was coated between the anode and YSZ electrolyte. The resulting polarization resistance and anodic overpotential with the SDC interlayer were 0.30 Ω cm2 and 0.035 V in H2 at 800 °C, demonstrating a reduction by factors of 3.2 and 3.4, respectively. The impedance data displayed that the coated SDC interlayer mainly affected the low frequency electrode process, indicating that the SDC interlayer played an important role in the promotion of the dissociation and diffusion processes of H2 oxidation reaction. [ABSTRACT FROM AUTHOR]

Highlights: [•] Cost-effective mechanical mixing method used for preparing Cu–SDC cermet anodes. [•] Optimization of the cermet anodes microstructure and composition. [•] Outstanding low-temperature electrochemical performance. [Copyright &y& Elsevier]

Abstract: The effects of B2O3–Bi2O3–PbO (BBP) frit on the electrochemical performance, electrical conductivity, and thermal expansion of LaBaCo2O5+δ (LBCO) cathode were investigated. BBP frit was found to be effective in lowering the sintering temperature of LBCO cathode by about 200 °C and in improving its electrochemical performance within the intermediate-temperature range of 600–800 °C. LBCO with 5 wt.% BBP frit cathode based on Sm0.2Ce0.8O1.9 electrolyte showed the best electrochemical performance, i.e., the lowest area-specific resistance (ASR) and cathodic overpotential. The ASR values were about 64.1%, 66.1%, and 74.5% lower than those of LBCO at 700, 750, and 800 °C, respectively. The cathodic overpotential decreased from 51.0 mV for LBCO to 8.2 mV at a current density of 0.2 A cm−2 at 700 °C. The electrical conductivity of LBCO with 5 wt.% BBP frit was about 320–330 S cm−1 at 600–800 °C in air. [Copyright &y& Elsevier]

A strategy based on laser micro-processing was proposed to improve the solid oxide fuel cell performance by modifying electrode/electrolyte interface with a “dimples array” structure. Electrochemistry impedance spectroscopy (EIS) results showed that both ohmic and polarization resistance of single cell were decreased remarkably after interfacial modification. Moreover, the maximum power density of modified cell was increased by up to 58% at 800 °C. The microstructural images of electrode/electrolyte interface indicated that the structured interface extended the triple-phase boundary (TPB) length for electrochemical reaction, which led to the major improvement in the cell performance. [ABSTRACT FROM AUTHOR]

The LaBaCo2O5+δ−x wt.% Bi2O3 (LBCO-xBi2O3, x=10, 20, 30, and 40) were prepared as composite cathodes for intermediate-temperature solid oxide fuel cells (IT-SOFCs) via the conventional mechanical mixing method. The effect of Bi2O3 on polarization resistance, overpotential, and long-term stability of the LBCO cathode was investigated. An effective sintering aid for LBCO cathode, Bi2O3 not only lowers its sintering temperature by ~200°C, but also improves the electrochemical performance within the intermediate temperature range of 600–800°C. Electrochemical impedance spectroscopy measurements showed that the addition of 20wt% Bi2O3 to LBCO exhibited the lowest area-specific resistance of 0.020Ωcm2 at 800°C in air, which was about a seventh of that of the LBCO cathode at the same condition. At a current density of 0.2Acm−2, the cathodic overpotential of LBCO-20Bi2O3 was about 12.6mV at 700°C, while the corresponding value for LBCO was 51.0mV. Compared to B2O3–Bi2O3–PbO frit, the addition of Bi2O3 significantly improved the long-term stability of cathode. Therefore, LBCO-20Bi2O3 can be a promising cathode for IT-SOFCs. [ABSTRACT FROM AUTHOR]