A comparative study of electrochemical methods on Pt–Ru DMFC anode catalysts: The effect of Ru addition

In the present study comparative electrochemical study of methanol electro-oxidation reaction, the effect of ruthenium addition and experimental parameters on methanol electro-oxidation reaction at high performance carbon supported Pt and Pt–Ru catalysts have been studied by cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) in H₂SO₄ (0.05–2.00 M) + CH₃OH (0.01–4.00 M) at 20–70 °C. Tafel plots for the methanol oxidation reaction on Pt and Pt–Ru catalysts show reasonably well-defined linear region with the slopes of 128–174 mV dec⁻¹(α = 0.34–0.46). The activation energies from Arrhenius plots have been found as 39.06–50.65 kJ mol⁻¹. As a result, methanol oxidation is enhanced by the addition of ruthenium. Furthermore, Pt–Ru (25:1) catalyst shows best electro–catalytic activity, higher resistance to CO, and better long term stability compared to Pt–Ru (3:1), Pt–Ru (1:1), and Pt. Finally, the EIS measurements on Pt–Ru (25:1) catalyst reveals that methanol electro-oxidation reaction consists of two process: methanol dehydrogenation step at low potentials (<700 mV) and the oxidation removal of CO_ads by OH_ads at higher potentials (>700 mV).     

Nanoparticles of Pt/HxMoO3 electrodeposited in poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) as the electrocatalyst for methanol oxidation

Nanoparticles of platinum and hydrous molybdenum oxide (Pt/H_xMoO₃) were successfully electrodeposited onto poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) (PEDOT-PSS) film by chronocoulometry (0.2 C). Various loadings of Pt/H_xMoO₃ particles onto the PEDOT-PSS electrode were achieved using the co-deposition technique. The existence of Pt/H_xMoO₃ particles was determined through characterization by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis. XPS results revealed that deposited Pt and molybdenum were metallic Pt and H_xMoO₃, respectively. XRD analysis showed a decrease of Pt crystalline facets for the incorporation of H_xMoO₃ into PEDOT-PSS-Pt, indicating a strong interaction between Pt and H_xMoO₃. Scanning electron microscopy (SEM) results revealed a uniform dispersion of Pt/H_xMoO₃ particles, with the particle size of 70–90 nm, in the PEDOT-PSS matrix. The cyclic voltammetry study and chronopotentiometry measurements demonstrated that the PEDOT-PSS-Pt/H_xMoO₃ electrode had superior electrocatalytic activity of methanol oxidation with less CO poisoning. The presence of amorphous H_xMoO₃ particles on the Pt surface minimized CO poisoning of methanol oxidation.     

Electrochemical impedance studies on carbon supported PtRuNi and PtRu anode catalysts in acid medium for direct methanol fuel cell

The anodic Pt–Ru–Ni/C and the Pt–Ru/C catalysts for potential application in direct methanol fuel cell (DMFC) were prepared by chemical reduction method. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measurements were carried out by using a glassy carbon working electrode covered with the catalyst powder in a solution of 0.5 mol L⁻¹ CH₃OH and 0.5 mol L⁻¹ H₂SO₄ at 25 °C. EIS information discloses that the methanol electrooxidation on the Pt–Ru–Ni/C catalyst at various potentials shows different impedance behaviors. The mechanism and the rate-determining step of methanol electrooxidation are changed with increasing potential. Its rate-determining steps are the methanol dehydrogenation and the oxidation reaction of adsorbed intermediate CO_ads and OH_ads in low (400–500 mV) and high (600–800 mV) potentials, respectively. The catalytic activity of the Pt–Ru–Ni/C catalyst is higher for methanol electrooxidation than that of the Pt–Ru/C catalyst. Its tolerance performance to CO formed as one of the intermediates of methanol dehydrogenation is also better than that of the Pt–Ru/C catalyst.     

Effect of chemisorbed CO on MoOx–Pt/C electrode on the kinetics of hydrogen oxidation reaction

The influence of poisoning of MoO_x–Pt catalyst by CO on the kinetics of H₂ oxidation reaction (HOR) at MoO_x–Pt electrode in 0.5 mol dm⁻³ HClO₄ saturated with H₂ containing 100 ppm CO, was examined on rotating disc electrode (RDE) at 25 °C. MoO_x–Pt nano-catalyst prepared by the polyole method combined with MoO_x post-deposition was supported on commercial carbon black, Vulcan XC-72. The MoO_x–Pt/C catalyst was characterized by TEM technique. The catalyst composition is very similar to the nominal one and post-deposited MoO_x species block only a small fraction of the active Pt particle surface area. MoO_x deposition on the carbon support can be ruled out from the EDAX results and from the low mobility of these oxides under used conditions. Based on Tafel–Heyrovsky–Volmer mechanism the corresponding kinetic equations from a dual-pathway model were derived to describe oxidation current–potential behavior on RDE over entire potential range, at various CO coverages. The polarization RDE curves were fitted with derived polarization equations according to the proposed model. The fitting showed that the HOR proceeded most likely via the Tafel–Volmer (TV) pathway. A very high electrocatalytic activity observed at MoO_x–Pt catalyst for the hydrogen oxidation reaction in the presence of 100 ppm CO is achieved through chemical surface reaction of adsorbed CO with Mo surface oxides.     

HxMoO3-assisted deposition of platinum nanoparticles on MWNTs for electrocatalytic oxidation of methanol

Platinum nanoparticles were loaded on multi-walled carbon nanotubes (MWNTs) by using ethylene glycol as reductant and with the assistance of hydrogen molybdenum bronze (H_xMoO₃, 0 < x ≤ 2) for the electrocatalytic oxidation of methanol. In this approach, MWNTs were modified by H_xMoO₃ and used as the support for platinum nanoparticles. The XRD and TEM characterizations indicate that the average particle size of platinum supported by the modified MWNTs (Pt/H_xMoO₃-modified-MWNTs) is 3.4 nm, smaller than that (4.3 nm) of the platinum supported by the unmodified MWNTs (Pt/MWNTs). The voltammetric and chronoamperometric experiments show that Pt/H_xMoO₃-modified-MWNTs exhibits better electrocatalytic activity toward methanol oxidation than Pt/MWNTs, although the former has a less platinum loading (4.6 wt%) than the latter (6.0 wt%). The mechanism on the assistance of H_xMoO₃ to the platinum deposition was discussed.     

Electroactivity of high performance unsupported Pt–Ru nanoparticles in the presence of hydrogen and carbon monoxide

The electrochemical activity of high performance unsupported (1:1) Pt–Ru electrocatalyst in the presence of hydrogen and carbon monoxide has been studied using the thin-film rotating disk electrode (RDE) technique. The kinetic parameters of these reactions were determined in H₂- and CO-saturated 0.5 M H₂SO₄ solutions by means of cyclic voltammetry, including CO stripping, and RDE voltammetry. Pt–Ru/Nafion inks were prepared in one step with different Nafion mass fractions, allowing determining the ionomer influence in electrocatalytic response and obtaining the kinetic current density in absence of mass-transfer effects, being 41 and 12 mA cm² (geometrical area), for H₂ and CO oxidation, respectively. These values correspond to mass activities of 1.37 and 0.40 A mg_Pt¹ and to specific activities of 1.52 and 0.44 mA cm_Pt². The Tafel analysis confirmed that hydrogen oxidation was a two-electron reversible reaction, while CO oxidation exhibited an irreversible behavior with a charge-transfer coefficient of 0.42. The kinetic results for CO oxidation are in agreement with the bifunctional theory, in which the reaction between Pt–CO and Ru–OH is the rate-determining step. The exchange current density for hydrogen reaction was 0.28 mA cm² (active surface area), thus showing similar kinetics to those found for carbon-supported Pt and Pt–Ru electrocatalyst nanoparticles.     

Catalytic oxidation of methanol on molybdate-modified platinum electrode in sulfuric acid solution

The catalysis of methanol oxidation on molybdate-modified platinum was studied by using linear sweep voltammetry (LSV), cyclic voltammetry (CV) and chronoamperometry in the solutions with H₂SO₄ concentrations from 0.5 to 4.5 M. It was found that methanol oxidation was catalyzed on the modified platinum by lowering methanol oxidation potential and promoting methanol oxidation current. There was the strongest catalysis in 3.7 M H₂SO₄ solution. In this solution, methanol oxidation took place on the modified platinum at the potential 0.2 V more negatively than on the non-modified platinum and the steady oxidation current of methanol on the modified platinum at 0.7 V versus SCE was 10 times that on the non-modified platinum. Molybdates were reduced to adsorbed hydrogen molybdenum(IV) bronzes on platinum in H₂SO₄ solution at a very negative potential. The amount of reduced molybdates decreased with decreasing H₂SO₄ concentrations. The reduced molybdates were oxidized to different forms of hydrogen molybdenum bronzes (H_xMoO₃, 0<x<2) depending on the H₂SO₄ concentration. Platinum was modified by these hydrogen molybdenum bronzes, but under-modified in the solution with lower H₂SO₄ concentration and over-modified in the solution with higher H₂SO₄ concentration. The catalysis of methanol oxidation was weakened when the platinum was under- or over-modified.     

Carbon nanofibre/hydrous RuO2 nanocomposite electrodes for supercapacitors

Amorphous RuO₂·xH₂O and a VGCF/RuO₂·xH₂O nanocomposite (VGCF = vapour-grown carbon fibre) are prepared by thermal decomposition. The morphology of the materials is investigated by means of scanning electron microscopy. The electrochemical characteristics of the materials, such as specific capacitance and rate capability, are investigated by cyclic voltammetry over a voltage range of 0–1.0 V at various scan rates and with an electrolyte solution of 1.0 M H₂SO₄. The specific capacitance of RuO₂·xH₂O and VGCF/RuO₂·xH₂O nanocomposite electrodes at a scan rate of 10 mV s⁻¹ is 410 and 1017 F g⁻¹, respectively, and at 1000 mV s⁻¹ are 258 and 824 F g⁻¹, respectively. Measurements of ac impedance spectra are made on both the electrodes at various bias potentials to obtain a more detailed understanding of their electrochemical behaviour. Long-term cycle-life tests for 10⁴ cycles shows that the RuO₂·xH₂O and VGCF/RuO₂·xH₂O electrodes retain 90 and 97% capacity, respectively. These encouraging results warrant further development of these electrode materials towards practical application.     

Effect of the catalyst composition in the Ptx(Ru–Ir)1−x/C system on the electro-oxidation of methanol in acid media

The effect of variations in the composition for ternary catalysts of the type Pt_x(Ru–Ir)_1−x/C on the methanol oxidation reaction in acid media for x values of 0.25, 0.50 and 0.75 is reported. The catalysts were prepared by the sol–gel method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic absorption spectroscopy (AAS) and energy dispersive X-ray (EDX) analyses. The nanometric character (2.8–3.2 nm) of the sol–gel deposits was demonstrated by XRD and TEM while EDX and AAS analyses showed that the metallic ratio in the compounds was very near to the expected one. Cyclic voltammograms for methanol oxidation revealed that the reaction onset occur at less positive potentials in all the ternary catalysts tested here when compared to a Pt_0.75–Ru_0.25/C (E-Tek) commercial composite. Steady-state polarization experiments (Tafel plots) showed that the Pt_0.25(Ru–Ir)_0.75/C catalyst is the more active one for methanol oxidation as revealed by the shift of the reaction onset towards lower potentials. In addition, constant potential electrolyses suggest that the addition of Ru and Ir to Pt decreases the poisoning effect of the strongly adsorbed species generated during methanol oxidation. Consequently, the Pt_0.25(Ru–Ir)_0.75/C composite catalyst is a very promising one for practical applications.     

The discharge reaction mechanism of the MoO3 electrode in organic electrolytes

Discharge and charge reactions of MoO₃ electrodes in organic Li⁺ electrolytes are shown to be reversible topotactic redox processes of layered molybdenum bronzes Li_x⁺[MoO₃]^x−. The kinetically accessible charge range amounts to 0.1 x < 1.5 with the lower limit of x depending on the precedent cathodic load. Complete re-oxidation to the binary oxide is kinetically hindered presumably as a result of small structural changes. The process is strongly affected by the size of the electrolyte cation, whereas no dependence on the anion species was observed. Reduction beyond x = 1.5 is at least partially associated with irreversible changes in the oxide structure. Similar reactions were found for non-stoichiometric molybdenum oxides e.g. Mo₁₈M₅₂ and Mo₈O₂₃.     

Electrochemical and structural studies of the carbon-coated Li[CrxLi(1/3−x/3)Ti(2/3−2x/3)]O2 (x = 0.3, 0.35, 0.4, 0.45)

A series of carbon-coated layered structured Li[Cr_xLi_(1/3−x/3)Ti_(2/3−2x/3)]O₂ samples (0.3 ≤ x ≤ 0.45) were prepared. Among them, the sample of x = 0.4 shows the highest initial reversible capacity of 207 mAh g⁻¹ at 30 mA g⁻¹ in 2.5–4.4 V. The reversible Li-storage capacities for the samples with high x values (x = 0.4, 0.45) faded slightly while the samples with low Cr content (x = 0.3 and 0.35) showed a capacity increase upon cycling. It was found that the relative intensity ratio of (0 0 3) peak to (1 0 4) peak (R_(0 0 3) = I_(0 0 3)/I_(1 0 4)) is influenced strongly by x value in as-prepared samples. The samples of x = 0.35 and 0.4 turn to a similar structure with low R_(0 0 3) value during cycling. These phenomena indicate that the cation mixing of Cr³⁺ in the lithium layer occurs in as-prepared samples and became more significant upon delithiation and lithiation. This is supposed being a necessary process for Cr-based layered structure materials possessing electrochemical reactivates. The occurrence of the cation mixing is beneficial from the local lattice distortion caused by the short-range ordering between Ti and Li. This is supposed to be helpful for the migration of Cr⁶⁺ and Cr³⁺ at tetrahedral and octahedral sites. Different from the case of LiNiO₂, the cation mixing is essential for the transport and storage of lithium in the carbon-coated Li–Cr–Ti–O layered compounds.     

Platinum nanoparticles embedded in layer-by-layer films from SnO2/polyallylamine for ethanol electrooxidation

Self-assembled films from SnO₂ and polyallylamine (PAH) were deposited on gold via ionic attraction by the layer-by-layer (LbL) method. The modified electrodes were immersed into a H₂PtCl₆ solution, a current of 100 μA was applied, and different electrodeposition times were used. The SnO₂/PAH layers served as templates to yield metallic platinum with different particle sizes. The scanning tunnel microscopy images show that the particle size increases as a function of electrodeposition time. The potentiodynamic profile of the electrodes changes as a function of the electrodeposition time in 0.5 mol L⁻¹ H₂SO₄, at a sweeping rate of 50 mV s⁻¹. Oxygen-like species are formed at less positive potentials for the Pt–SnO₂/PAH film in the case of the smallest platinum particles. Electrochemical impedance spectroscopy measurements in acid medium at 0.7 V show that the charge transfer resistance normalized by the exposed platinum area is 750 times greater for platinum electrode (300 kΩ cm²) compared with the Pt–SnO₂/PAH film with 1 min of electrodeposition (0.4 kΩ cm²). According to the Langmuir–Hinshelwood bifunctional mechanism, the high degree of coverage with oxygen-like species on the platinum nanoparticles is responsible for the electrocatalytic activity of the Pt–SnO₂/PAH concerning ethanol electrooxidation. With these features, this Pt–SnO₂/PAH film may be grown on a proton exchange membrane (PEM) in direct ethanol fuel cells (DEFC).     

Oxidation of methanol on perovskite-type La2-xSrxNiO4 (0 ≤ x ≤ 1) film electrodes modified by dispersed nickel in 1 M KOH

Finely-dispersed nickel particles are electrodeposited on high surface-area perovskite-type La_2-xSr_xNiO₄ (0 ≤ x ≤ 1) electrodes for possible use in a direct methanol fuel cell (DMFC). The study is conducted by cyclic voltammetry, chronoamperometry, impedance spectroscopy and anodic Tafel polarization techniques. The results show that the apparent electrocatalytic activities of the modified oxide electrodes are much higher than those of unmodified electrodes under similar experimental conditions; the observed activity is the greatest with the modified La_1.5Sr_0.5NiO₄ electrode. At 0.550 V (vs. Hg|HgO) in 1 M KOH + 1 M CH₃OH at 25 °C, the latter electrode delivers a current density of over 200 mA cm⁻², whereas other electrodes of the series produce relatively low values (65–117 mA cm⁻²). To our knowledge, such high methanol oxidation current densities have not been reported on any other non-platinum electrode in alkaline solution. Further, the modified electrodes are not poisoned by methanol oxidation intermediates/products.     

Electrochemical performance of Ba0.5Sr0.5CoxFe1−xO3−δ (x = 0.2–0.8) cathode on a ScSZ electrolyte for intermediate temperature SOFCs

Intermediate temperature solid oxide fuel cell cathode materials (Ba, Sr)Co_xFe_1−xO_3−δ [x = 0.2–0.8] (BSCF), were synthesized by a glycine-nitrate process (GNP) using Ba(NO₃)₂, Sr(NO₃)₂, Co(NO₃)₂·6H₂O, and Fe(NO₃)₃·9H₂O as starting materials and glycine as an oxidizer and fuel. Electrolyte-supported symmetric BSCF/GDC/ScSZ/GDC/BSCF cells consisting of porous BSCF electrodes, a GDC buffer layer, and a ScSZ electrolyte were fabricated by a screen printing technique, and the electrochemical performance of the BSCF cathode was investigated at intermediate temperatures (500–700 °C) using AC impedance spectroscopy. Crystallization behavior was found to depend on the pH value of the precursor solution. A highly acidic precursor solution increased the single phase perovskite formation temperature. In the case of using a precursor solution with pH 2, a single perovskite phase was obtained at 1000 °C. The thermal expansion coefficient of BSCF was gradually increased from 24 × 10⁻⁶ K⁻¹ for BSCF (x = 0.2) to 31 × 10⁻⁶ K⁻¹ (400–1000 °C) for BSCF (x = 0.8), which resulted in peeling-off of the cathode from the GDC/ScSZ electrolyte. Only the BSCF (x = 0.2) cathode showed good adhesion to the GDC/ScSZ electrolyte and low polarization resistance. The area specific resistance (ASR) of the BSCF (x = 0.2) cathode was 0.183 Ω cm² at 600 °C. The ASR of other BSCF (x = 0.4, 0.6, and 0.8) cathodes, however, was much higher than that of BSCF (x = 0.2).     

A novel binary Pt3Tex/C nanocatalyst for ethanol electro-oxidation

The Pt₃Te_x/C nanocatalyst was prepared and its catalytic performance for ethanol oxidation was investigated for the first time. The Pt₃Te/C nanoparticles were characterized by an X-ray diffractometer (XRD), transmission electron microscope (TEM) and energy dispersive X-ray spectroscopy equipped with TEM (TEM-EDX). The Pt₃Te/C catalyst has a typical fcc structure of platinum alloys with the presence of Te. Its particle size is about 2.8 nm. Among the synthesized catalysts with different atomic ratios, the Pt₃Te/C catalyst has the highest anodic peak current density. The cyclic voltammograms (CV) show that the anodic peak current density for the Pt₃Te/C, commercial PtRu/C and Pt/C catalysts reaches 1002, 832 and 533 A g⁻¹, respectively. On the current–time curve, the anodic current on the Pt₃Te/C catalyst was higher than those for the catalysts reported. So, these findings show that the Pt₃Te/C catalyst has uniform nanoparticles and the best activity among the synthesized catalysts, and it is better than commercial PtRu/C and Pt/C catalysts for ethanol oxidation at room temperature.     

Characterization of Cu,Ag and Pt added La0.6Sr0.4Co0.2Fe0.8O3−δ and gadolinia-doped ceria as solid oxide fuel cell electrodes by temperature-programmed techniques

Cu, Ag and Pt added La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ (LSCF) and gadolinia-doped ceria (GDC) were analyzed by the temperature-programmed techniques for their characteristics as either the cathode or the anode of the solid oxide fuel cells (SOFCs). Temperature-programmed oxidation using CO₂ was used to characterize the cathode materials while temperature-programmed reduction (TPR) using H₂ and TPR using CO were used to characterize the anode materials. These techniques can offer an easy screening of the materials as the SOFC electrodes. The effects of adding Cu, Ag and Pt to LSCF for the cathodic reduction activity and the anodic oxidation activity are different—Cu > Ag > Pt for reduction and Pt > Cu > Ag for oxidation. The CO oxidation activities are higher than the H₂ oxidation activities. Adding GDC to LSCF can increase both reduction and oxidation activities. The LSCF–GDC composite has a maximum activity for either reduction or oxidation when LSCF/GDC is 2 in weight.     

Platinum/vivianite bifunction catalysts for DMFC

Bi-functional catalysts are used to solve the poisoning problem caused by carbon monoxide (CO) which is the intermediate of direct methanol fuel cells (DMFCs). Flower-like vivianite (Fe₃(PO₄)₂·8H₂O) spheres with diameter around 10 μm are originally used as supports of Pt to form bifunction catalysts. The cyclic voltammetry in 1 M H₂SO₄ indicates that the electrochemical surface area (ECSA) of Pt reduced on as-prepared vivianite (Pt/Vi) was 105, greater than 91 m² g⁻¹ for the commercial Pt/C. Besides, Pt/Vi reveals the less CO poisoning effects, including the greater mass activity in methanol oxidation and the lower onset potential in CO-stripping than Pt/C. These excellent performances on electrolyzes are related to the chemical state of Fe³⁺ and the coexistence of Pt⁰ and Pt²⁺ in Pt/Vi. The former activates the water and yields Fe-OH_ads at lower potential and the latter may offer an easy way of electron transition.     

A study on pulse plating amorphous Ni–Mo alloy coating used as HER cathode in alkaline medium

The amorphous Ni–Mo film with high HER (hydrogen evolution reaction) activity was obtained by pulse plating. The optimum electrodeposition conditions with respect to HER overpotential were determined, e.g. Na₂MoO₄·2H₂O concentration, current density and duty cycle. Correspondingly, the compositions and components of the Ni–Mo coatings with various molybdenum contents were investigated systematically. The results showed that when the ratio of nickel and molybdenum concentrations in the electrodeposition bath is lower than 1 (mol%), the molybdenum content in the coating decreases with the increasing Na₂MoO₄·2H₂O concentration, while the corresponding HER overpotential of the Ni–Mo film increases. The amorphous Ni–Mo coating was obtained when the molybdenum content was c.a. 30 mass%, which shows high HER activity (η₂₀₀ = 62 mV at 200 mA cm⁻² and 80 °C) and excellent corrosion resistance. After galvano-static electrolysis for 100 h in 33 mass% NaOH solution, the amorphous structure was destroyed due to the dissolution of molybdenum.     

Thermal stabilities of nanoporous metallic electrodes at elevated temperatures

Currently Pt-based metals are the best catalytic electrodes for fuel cells at operating temperatures below 500 °C. Pure platinum electrodes suffer degradation of microstructure over time at elevated temperatures due to Ostwald ripening. In this paper, better thermal stability of Pt–Ni nanoporous thin films relative to pure Pt is reported. Based on ab initio calculations, it was found that both the surface energy of a Pt_0.7Ni_0.3 cluster and the energy change of the Pt–Ni alloy cluster upon ripening on yttria stabilized zirconia (YSZ) solid electrolyte were lower than pure Pt. This suggested a better thermal stability of Pt_0.7Ni_0.3 than Pt. In addition, annealing impacts on microstructures and properties of nanoporous Pt and Pt–Ni alloy thin films were examined experimentally. SEM images show dramatic porosity reduction for pure Pt after annealing at temperatures of 400–600 °C but insignificant microstructure change for Pt–Ni nanoporous thin films. As a result, in solid oxide fuel cells using nanoporous Pt–Ni cathodic catalysts instead of pure Pt, better stability, lower electrode impedances, and higher power densities were achieved at elevated operating temperatures (350–500 °C).     

Evaluation of Ba2(In0.8Ti0.2)2O5.2−n(OH)2n as a potential electrolyte material for proton-conducting solid oxide fuel cell

Electrochemical measurements of fuel cells based on proton conductor electrolyte Ba₂(In_0.8Ti_0.2)₂O_5.2−n(OH)_2n and prepared through a tape casting process and a co-pressing of anode-composite powder and electrolyte tape were performed at 500 °C under wet H₂. The varying parameter between the prepared cells was the thickness of the electrolyte that can be controlled during the tape casting process. The maximum power density was obtained for the cell with the thinnest electrolyte (35 μm) and was about 22 mW cm⁻² with an ohmic resistance about 2 Ω cm² at 500 °C.