Fine‐microstructure Mediated Efficient Hydrogen Oxidation in Ni/YSZ Anode Fabricated from Novel Co‐precipitation Derived Nanocomposites

Abstract

Fine‐microstructure mediated efficient hydrogen oxidation was demonstrated on nickel/yttria‐stabilised zirconia (Ni/YSZ) anode fabricated from NiO/YSZ nanocomposite particles, synthesised via a novel co‐precipitation method using YSZ nanoparticles with the average size of 3 nm. Transmission electron microscopy image revealed that nanocomposite particles calcined at 600 °C consisted of homogeneously distributed NiO and YSZ nanocrystals, approximately 5 nm large. The Ni/YSZ anode was fabricated by sintering the screen‐printed nanocomposites at 1,300 °C and their subsequent reduction. The anode had a uniform porous microstructure consisting of fine grains in the range of 200–300 nm, and exhibited quite low area‐specific resistance (ASR) of 2.29, 0.43 and 0.15 Ω cm2 at 600, 700 and 800 °C, respectively.

Electrochemical Study of a SOFC with Various H2‐CO‐CH4‐CO2‐N2 Gaseous Mixtures

“…According to the lower value of the slope at 0.8 V than at OCV, a Rp decrease is observed and this decrease is higher for R2. Moreover, the variations of R2 with T (curve (a) of Figure 5) are lower than at OCV, in agreement with [26,35] and the R3 value (curve (b) of Figure 5) seems depend slightly on the temperature. At 0.8 V, the part of the resistance of the cell due to electrolyte (R1/Rp) is drastically higher than that at OCV.…”

“…It can be fitted by the electrical equivalent circuit L + R1 + (R2//CPE2) + (R3//CPE3), presented on Figure 3A, which is classically used for porous SOFC electrodes [23], and is convenient for Ni-YSZ-based SOFC [24][25][26]. At lower temperatures (curve (b) of Figure 2), and as it has been also depicted in literature for Ni-YSZ electrodes [26], the first loop is more depressed, and the diagram must be fitted by the electrical equivalent circuit L + R1 + (R2A//CPE2A) + (R2B//CPE2B) + (R3//CPE3) ( Figure 3B). The inductance L, related to the wires, ranges between 0.9 and 1.1 10 -6 H, in agreement with literature with a similar testing set-up [27].…”

Mechanically Assisted Deposition of Nikel Oxide–Ytttria Stabilized Zirconia Nanocomposite Film and its Microstructural Evolution for Solid Oxide Fuel Cells Anode Application

“…The SSAs characterized by BET method were 75, 28, and 10 m 2 /g for the nanocomposite particles synthesized at 600°C, 800°C, and 1000°C for 6 h in air, respectively. A novel co‐precipitation method with an aqueous colloidal suspension of YSZ (~3 nm) was also used to synthesize the NiO–YSZ nanocomposite particle with the highest SSA (120 m 2 /g) …”

“…The NiO in the composite anode is reduced to Ni metal on exposure to hydrogen at the beginning of SOFC operation. To date, various attempts have been performed to synthesize the composite particles for SOFC electrodes, using Pechini method, spray pyrolysis, co‐precipitation method, or mechanochemical reactions …”

“…For the wet‐colloidal processes, the nanocomposite particles are often coarsened. For example, when we synthesized NiO–YSZ nanocomposite particles, they were really needed to be coarsened by calcination (at 1000°C) for their stable and concentrated suspension preparation . The subsequent sintering of the coarsened particles requires generally high temperatures (1300°C or more) for anode electrode formation, which leads to limited surface area.…”