Short-term Durability Test Research Articles

Highly Porous Polypyrrole (PPy) Hydrogel Support for the Design of a Co-N-C Electrocatalyst for Oxygen Reduction Reaction.

Atomically dispersed metal-nitrogen-carbon (M-N-C) catalysts have emerged as one of the most promising platinum-group metal (PGM)-free cathode catalysts for oxygen reduction reaction (ORR). Among the various approaches to enhance the ORR performance of the catalysts, increasing the density of accessible active sites is of paramount importance. Thus, nitrogen-rich support with abundant porosity can be very propitious. Herein, we report a highly porous polypyrrole (PPy) hydrogel as a versatile support for the facile design of a Co-N-C electrocatalyst for ORR. The resulting Co-N-C catalyst with abundant micro- and mesoporous combinations demonstrates a half-wave potential (E1/2) of 0.825 V vs reversible hydrogen electrode (RHE) in O2-saturated 0.1M KOH with just 2.1 wt % Co content. The ORR performance reduces only 11 mV (E1/2) after 5000 cycles of accelerated durability test (ADT), portraying its excellent stability. The catalyst retains ≈83% of its original current during a short-term durability test at 0.8 V vs RHE for 25 h. Furthermore, the catalyst shows electron transfer approaching ≈4 with low H2O2 yield in the potential range 0.5-0.9 V vs RHE. This work provides a simple design strategy to synthesize M-N-C catalysts with increased accessible active site density and enhanced mass transport for ORR and other electrocatalytic applications.

Direct Deposition of Dense YSZ/Ni-YSZ Thin-Film Bilayers on Porous Anode-Supported Cells with High Performance and Stability

We present an approach for integrating a thin-film bilayer combination comprising a Ni(O)-YSZ nanocomposite layer and a YSZ thin-film electrolyte prepared using pulsed laser deposition into the architecture of porous Ni-YSZ-supported cells. Achieving a minimum bilayer thickness threshold of ~1.5 µm is found to be critical to achieve a high open circuit voltage value, as well as a significant decrease in the ohmic resistance to ~0.06 Ωcm2 at 750 °C and increase in maximum power density to 1.83 W/cm2. Short-term durability tests up to 45 h at a constant potential of 0.8 V showed stable operation with current densities reaching ~1.7 A/cm2. Cells utilizing thin-film bilayers can overcome issues associated degradation in conventionally sintered cells, in terms of maintaining excellent contact with the anode support and significantly suppressing Ni diffusion into the YSZ electrolyte.

The design and synthesis of a long-side-chain-type anion exchange membrane with a hydrophilic spacer for alkaline fuel cells

Outstanding alkaline stability and high conductivity make side-chain-type anion exchange membranes (AEMs) become one of the ideal materials for AEM fuel cells (AEMFCs). However, the hydrophobic alkyl spacer between polymer backbones and cationic groups in AEMs limited their performance in AEMFCs. Herein, we demonstrated the design and synthesis of long-side-chain-type AEMs containing a hydrophilic ethylene oxide (EO) spacer using an appropriate EO-based monomer via click reaction. The obtained PPO-O-40 membrane with EO spacers showed higher hydroxide conductivity (52.1 mS cm−1 at 20 °C) than its counterpart with an alkyl spacer (PPO–C-40). The improved chemical stability of the PPO-O-x membrane was validated by an alkaline stability test for soaking in 1 M NaOH at 60 °C for 864 h. More importantly, an AEMFC assembled with the PPO-O-40 membrane displayed an outstanding peak power of 690 mW cm−2 at 60 °C under the optimal relative humidity of the anode. The short-term durability test observed a voltage decay rate of 6.1 mV h−1 during the continuous operation for 8 h at 200 mA cm−2. This work provides an alternative way to design highly conductive and durable side-chain-type AEMs containing a hydrophilic spacer for alkaline fuel cell application.

A coking-tolerance dendritic anode with exceptional power density toward direct ethanol-fueled solid oxide fuel cells

The highly efficient utilization of liquid biofuels is a major challenge for the current economic society. As one of the most promising energy conversion devices, solid oxide fuel cells (SOFCs) offer a feasible approach to alleviate this problem, yet the output power is limited by the concentration loss. In this work, Ni-gadolinium doped ceria anode with dendritic microchannels is prepared to accelerate mass transport and boost the electrochemical performance of ethanol-fueled SOFCs. The peak power densities of button cells with dendritic anode achieve 1.66 and 1.37 Wcm−2 at 700 °C using wet hydrogen and dry ethanol as fuels, respectively. More importantly, the concentration polarization can be almost negligible when using 30 vol% dry ethanol as fuel. Simultaneously, the button cell shows a favorable coke tolerance in a 100 h short-term durability test. These results demonstrate that the dendritic microchannel for SOFCs is a high-efficiency solution to facilitate mass transfer and improve the electrochemical performance of hydrocarbon fuels.

Design and Performance Enhancement of Cobalt-Encapsulated Nitrogen-Doped Carbon Nanofiber Electrocatalyst through Ionic Liquid Modification for Efficient Oxygen Reduction

The design of platinum-group-metal-free (PGM-free) electrocatalysts with appreciable activity and durability toward the oxygen reduction reaction (ORR) in acidic environments is a big challenge. Here, we report an efficient oxygen reduction activity of a Co-encapsulated nitrogen-doped carbon with nanofiber networks and its ionic liquid-modified interface in an acidic medium. The robust structure of the nanofibers embedded on a rigid framework derived from a zeolitic imidazole framework (ZIF-67) delivers promising activity and durability to the catalyst comparable to the state-of-the-art Pt/C. The ionic-liquid-modified catalyst shows a half-wave potential of 0.71 V vs RHE in oxygen-saturated 0.5 M H2SO4 along with activity reduction by only 11 mV (E1/2) after 5000 cycles of the accelerated durability test. The catalyst also retains 71% of its original current during the short-term durability test. Furthermore, the electron transfer number and H2O2 yield of the catalyst during the ORR approaches 3.88–3.90 and 5.9–4.8% in the potential range 0.4–0.7 V vs RHE. The ORR performance of the ionic-liquid-modified catalyst is superior among all ionic liquid-based non-PGM catalysts reported so far in acidic media.

Effect of Catalyst Double Layer on Performance without Micro Porous Layer in Anode for High Temperature Polymer Electrolyte Membrane Fuel Cell

Catalyst double layer (CDL) structure on gas diffusion electrode (GDE) without microporous layer (MPL) is developed for the anode of high temperature polymer electrolyte membrane fuel cell (HT–PEMFC). Polytetrafluoroethylene and polyvinylidene fluoride is applied for the outer and inner layer as the hydrophobic binder for fabricating 3D electrode structure. The effect of Pt ratio in anode CDLs on the GDE performance was investigated by single cell test and electrochemical analysis using poly(benzimidazole) (PBI)–based membrane, with Pt loading under 0.3 mg/cm2 at ambient pressure air on 150℃. The results show that optimal CDL anodes present performance of 0.65V at 0.2A/cm2 and peak power density is 0.41W/cm2 at mass transfer region which is higher than conventional single layer anode with MPL. Furthermore, the 3D structure of the outer catalyst layer in anode read high catalyst utilization and preventing leakage of electrolyte with a short–term durability test shows good stability with PBI membrane.

Evaluation of Durability Performance of a Ru/MgO Catalyst for Ammonia Decomposition at an on-Site Hydrogen Fueling Station

Since ammonia (NH3) decomposition catalysts for on-site hydrogen fueling stations must possess at least 10 years of durability, an activity/durability evaluation technique that can estimate catalyst activity after several thousands of hours was developed based on short-term durability tests in the laboratory. It consists of a series of repetitive activity/durability tests: (a) thermal treatments in NH3 at a predetermined endurance temperature for a given time, followed by (b) activity measurements at a reaction temperature of 500 °C. The technique was utilized for accelerated-deterioration durability evaluation of a Ru/MgO catalyst. It was discovered that the NH3 conversion decreases almost linearly, as a function of the endurance time at all endurance temperatures. Furthermore, the Arrhenius equation was employed to explore the relationship between the deterioration rate and endurance temperature. This technique can be considered a crucial tool for predicting the durability of NH3 decomposition catalysts employed in H2 fueling stations.

Poly(terphenyl piperidinium) containing hydrophilic crown ether units in main chains as anion exchange membranes for alkaline fuel cells and water electrolysers

Poly(arylene piperidinium) polymers are recognized as promising anion exchange membrane (AEM) materials for alkaline fuel cell and water electrolysis, due to the aryl-ether free polyaromatic backbones and stable piperidinium cations. Herein, hydrophilic crown ether units have been introduced into poly(terphenyl piperidinium) (PDTP) by readily superacid-catalyzed polycondensation of dibenzo-18-crown-6 (DE), p-terphenyl and N-methyl-4-piperidine followed via quaternization. The obtained PDTP membranes showed much higher hydroxide conductivity than the control poly(terphenyl piperidinium) (PTP) sample without DE units, due to their high water uptake. The highest hydroxide conductivity of 110 mS/cm was reached at 80 °C for PDTP-10 (where 10 denoted the molar content of crown ether units) membrane with an ion exchange capacity (IEC) of 2.57 meq./g. The introduction of DE units alleviated the chemical degradation of PDTP membrane in 1 M NaOH at 80 °C as compared to the PTP membranes. Furthermore, membrane electrode assemblies based on PDTP-10 membrane shown a peak power density of 621 mW/cm2 at 60 °C in AEM fuel cells and a current density of 2000 mA/cm2 at 2.1 V for water electrolysers circulated with 1 M NaOH at 80 °C. The in-situ stability tests in fuel cells and water electrolysers also manifested that the chemical structure of PDTP-10 membrane remained intact during short-term durability tests under galvanostatic mode. The above results manifested that AEMs containing hydrophilic crown ether units in the polymer mainchain showed potential in the application for AEM based electrochemical devices.

A free-cobalt barium ferrite cathode with improved resistance against CO2 and water vapor for protonic ceramic fuel cells

The triple conducting (electron, oxygen-ion and proton) cathode is promising for protonic ceramic fuel cells (PCFCs). Heavy doping of Fe can impel BaZr 0.9 Y 0.1 O 3-δ to cross the electronic percolation threshold, forming the triple-conducting BaFe 0.8 Zr 0.1 Y 0.1 O 3-δ (BFZY) material. The partial A-site substitution with La is also designed to further optimize the properties of BFZY. Herein, a systematic study on Ba 0.95 La 0.05 Fe 0.8 Zr 0.1 Y 0.1 O 3-δ (BLFZY) cathode is conducted for searching potential free-cobalt PCFC cathodes with good tolerance for both CO 2 and water vapor. The XRD result indicates that BLFZY maintains stable cubic perovskite structure. The comprehensive analysis based on XRD, TG and TPD-CO 2 reveals that the BLFZY cathode exhibits an excellent tolerance for CO 2 and water vapor. The La doping also has a positive influence on the thermal expansion coefficient, electrical conductivity, and electrocatalytic activity. The anode-supported single cell with single-phase BLFZY cathode achieves a peak power density of 305 mW cm −2 and polarization resistance of 0.492 Ω cm 2 at 600 °C and maintains steady power output in the short-term durability test. This indicates that the BLFZY material is a good cathode candidate for PCFCs. • BLFZY shows good tolerance for both CO 2 and water vapor. • La dopant is favorable to reducing TEC and increasing electrical conductivity. • A peak power density of 305 mW cm −2 is reached at 600 °C.

Potential of corn husk fiber for reinforcing cemented soil with high water content

The objective of this study is to investigate the effect of corn husk fiber on properties of cemented soil with high water content. Five laboratory experiments including bleeding, flow, unconfined compression, splitting tension, and short term durability tests are conducted. The results reveal that fiber inclusion makes a contribution to the reduction of bleeding ratio and flow value. Besides, at cement content of 40 kg/m3, tensile strength and compressive strength of cemented specimens increase from 79% to 330% and from 26% to 119% when adding fiber from 3 to 15 kg/m3, respectively. The effect of fiber on tensile strength and compressive strength decreases with the increase in cement content. However, at each cement level, the enlargement of fiber content results in the reduction of loss of post-peak stress. Second tensile strength appears due to fiber inclusion and improves when fiber content increases. Under drying and wetting cycles, specimens with fiber inclusion show trivial damage, meanwhile, the cracks appear and propagate for specimens without fiber inclusion.

A hybrid Pt/NbO/CNTs catalyst with high activity and durability for oxygen reduction reaction in PEMFC

To improve the kinetics and durability of Pt-based electrodes toward the oxygen reduction reaction (ORR), high electroactive and stable catalysts were synthesized by depositing Pt over niobium oxide (NbO) supported on commercial multi-wall carbon nanotubes (CNTs). The Pt/NbO/CNTs, exhibits excellent electroactivity and stability toward ORR, reaching a high electroactivity of 57 mA mgPt−1, higher than the Pt/CNTs and commercial Pt/C (20% Pt/C HiSPEC™). Moreover, the developed Pt/NbO/CNTs demonstrated outstanding durability under accelerated stress testing (AST) according to load cycling and startup/shutdown stability protocols. Proton exchange membrane fuel cells (PEMFC) tests with an MEA fabricated using Pt/NbO/CNTs showed excellent performance, with a low Pt loading down to 0.15 mg cm−2, achieving a maximum power density of 772 mW cm−2. Furthermore, a short-term durability test in PEMFC demonstrated only a 4% loss on the maximum power density at 80 °C. The superior electrocatalytic activity and durability of Pt/NbO/CNTs can be ascribed to the anchoring effect of Pt nanoparticles over the NbO/CNTs hybrid support, showing that the developed Pt/NbO/CNTs is a promising durable electrocatalyst for PEMFC applications.

Novel high ionic conductivity electrolyte membrane based on semiconductor La0.65Sr0.3Ce0.05Cr0.5Fe0.5O3-δ for low-temperature solid oxide fuel cells

The p-type semiconductor La0.65Sr0.3Ce0.05Cr0.5Fe0.5O3-δ (CLSCrF) is for the first time composited with the ionic conductor Ce0.8Sm0.2O2-δ (SDC) to prepare high ionic conductivity electrolyte membranes for low-temperature solid oxide fuel cells (LT-SOFCs). Experimental results illuminate that the introduction of moderate semiconductor into ionic membrane can improve membrane's ionic conductivity, reduce cell's polarization resistance and accelerate the electrode reaction in cathode zone. With 30 wt% CLSCrF incorporated into the SDC membrane, the cell delivers a maximum power density of 837 mW cm−2 at 550 °C with the membrane ionic conductivity as high as 0.15 S cm−1. This conductivity value is nearly 2 times higher than that of the simplex ionic membrane SDC. The rectification characteristic test indicates that there is a physical junction effect in the CLSCrF-SDC cells, which can prevent electrons from passing through internally and avoid the short circuit problem effectively. Moreover, the short-term durability test reveals that the developed CLSCrF-SDC cell is capable of stably operating for 18 h at 550 °C under a fixed current density of 234 mA cm−2. This study suggests that the CLSCrF-SDC is a promising membrane to advance the LT-SOFCs development.

Effect of Surface-Specific Treatment by Infiltration into LaNi6Fe4O3- δ Cathodic Backbone for Solid Oxide Fuel Cells

In this study, the impact of various infiltrates on the kinetics and rate-limiting step of oxygen reduction reaction (ORR) is examined with LaNi0.6Fe0.4O3- δ (LNF) as the cathode backbone of a solid oxide fuel cells (SOFC). Five materials were infiltrated: LaNi1-xFexO3- δ, LaxSr1-xCoyFe1-yO3-δ (LSCF), La1-xSrxMnO3-δ (LSM), Gd1-xCexO2-δ (GDC) and Pr6O11. The dependence of electrode polarization resistance on the precursor concentration, temperature, oxygen partial pressure is presented with related discussions on ORR kinetics and rate-determining step for ORR. A one-step infiltration of all five materials resulted in a dramatic decrease in polarization resistance (Rp) and related activation energy (Ea), which is ascribed to a significant facilitation of surface processes such as dissociative adsorption with electron transfer and diffusion of oxygen intermediates. Finally, a short-term durability test in a Cr-containing environment indicated that the LSCF-infiltrated cell is susceptible to Cr poisoning unlike the GDC- or LNF-infiltrated cells as expected but advantageous in terms of morphological stability during operation.

Effects of mesoporous fillers on properties of polybenzimidazole composite membranes for high-temperature polymer fuel cells

In this study, we elucidated the effects of the addition of various mesoporous silicates (0–20 wt%) to the membranes used for high-temperature proton exchange membrane fuel cells (HT-PEMFCs) on cell performance. Two types of polybenzimidazole (PBI)-based hybrid membranes were prepared by homogeneously dispersing a predetermined amount of MCM-41 or SBA-15 within the PBI matrix. Compared to the pure PBI membrane, those with MCM-41 and SBA-15 exhibited significantly enhanced phosphoric acid doping and better mechanical properties, leading to improved HT-PEMFC performance and reduced acid migration. However, the membranes with 20 wt% silicate showed inferior performance compared to those with 10 wt% silicate. In addition, the membranes with SBA-15 exhibited noticeable aggregation, lower phosphoric acid doping, and greater phosphoric acid migration during the leaching test than did the membranes with MCM-41. Finally, during the short-term durability test, the PBI/MCM-41 (10 wt%) membrane showed the best performance (maximum power density of 310 mW cm−2).

Effects of using two transition metals in the synthesis of non-noble electrocatalysts for oxygen reduction reaction in direct methanol fuel cell

Five different bimetallic non-precius metal catalysts for oxygen reduction reaction (ORR) are synthesized by different combinations of two transition metal (Fe, Co, Cu, Zn) phthalocyanine precusrsors. The aim of this study is to investigate the effects of the different combinations of two transition metals on the physico-chemical and ORR electrocatalytic activity of the catalysts. The precursors were mixed, impregnated on a mesoporous silica used as a hard template, and pyrolyzed under inert atmosphere at 800 °C. After the template removal, the catalysts were characterized via BET, FESEM, and XPS. TGA-MS analysis was also performed on the catalysts precursors to simulate their behaviour during the pyrolysis, detecting the evolved gases. The results show that both the physico-chemical features and the ORR activity and selectivity in acidic medium (measured by RDE-RRDE technique) are strongly influenced by the transition metals pair used. In particular, the most effective transition metals pair to get a more performing ORR catalyst is Co-Zn. The catalysts are also tested in direct methanol fuel cell, including a short-term durability test. The durability of the best perfroming Co-Zn catalyst is improved compared to a similar catalyst synthesized using Fe. The possibility of tuning the catalysts features by combining different transition metals enables to increase the catalyst durability, the production yield during the synthesis (enabling to recover more material after the pyrolysis), and the surface N fixation.

Fe-N/C catalysts for oxygen reduction reaction supported on different carbonaceous materials. Performance in acidic and alkaline direct alcohol fuel cells

Four carbonaceous materials (acetylene black, multi-walled carbon nanotubes, and two carbon materials synthesized by hard-template method) were used as a support to synthesize four Fe-N/C non-noble metal (NNM) catalysts for oxygen reduction reaction (ORR) by impregnation with a FeIII–1,10-phenanthroline complex and subsequent pyrolysis in inert atmosphere. The catalysts were characterized by N2 physisorption, XPS, Raman and TGA, and their ORR activity was measured by rotating disk electrode (RDE) in both acidic and alkaline conditions. The catalysts were tested in an acidic direct methanol fuel cell (DMFC) and in an alkaline direct ethanol fuel cell (DEFC). Due to the slower ORR kinetics at low pH, the features of the carbon support have an important influence on the performance in acidic DMFC. Conversely, the enhanced ORR kinetics at high pH, makes the influence of the C-support less evident in alkaline DEFC. Moreover, the short-term durability test in DMFC for our best Fe-N/C catalysts showed better results compared to Pt/C benchmark catalyst. The durability in alkaline DEFC is poor, even though the initial performance can be partially recovered after purge-drying and reactivation.

Short-Term Durability of Hemp Fibers

Short-term durability tests on hemp-fiber confined concrete cylinders made up of one layer of hemp-fiber bundles were conducted to study their behavior. Compression test was performed after wetting and drying cycles in both water and seawater. Moreover, uniaxial tension test on hemp-fiber bundles was conducted to study the effect of extended W/D cycles and prolonged exposure to moisture (1,800 hours). Hemp-fiber confined concrete cylinders showed promising results where there was no significant change in both compressive strength and ductility in comparison to control wrapped cylinders. Regarding tensile testing, after prolonged exposure to water, hemp-fiber bundles were completely destroyed. On the other hand, epoxy coating provided a suitable protected configuration to hemp-fiber bundles. Resistance to seawater was highly apparent in the conservation of tensile stresses. Therefore, natural fibers could be recommended as an alternative to synthetic fibers while taking their drawbacks into account.

Performance of a Fe-N-C catalyst for the oxygen reduction reaction in direct methanol fuel cell: Cathode formulation optimization and short-term durability

A non-noble metal (NNM) catalyst for oxygen reduction reaction (ORR) was synthesized using Fe(II)-phthalocyanine as unique source of Fe, N, and C, and SBA-15 ordered mesoporous silica as templating agent, resulting in a material with an extremely high specific surface area and a high microporosity (around 50%). FESEM, FTIR and Raman analyses were performed to investigate the morphology and the physicochemical properties of the catalyst. The ORR activity and the methanol tolerance were tested in rotating disk electrode (RDE), and the selectivity towards a complete 4-electrons reduction was investigated by rotating ring disk electrode (RRDE) test and hydrogen peroxide reduction test in RDE, showing very promising results. Thus, the Fe-N-C catalyst was tested at the cathode of a DMFC after determination of the optimal electrode formulation regarding catalyst loading and Nafion® content, showing a maximum power density of 20mWcm−2 at 90°C. A short term durability test to assess the behavior of both the Fe-N-C and the Pt/C catalysts was conducted on the DMFC, showing a better performance of the non-noble catalyst. Thus, the Fe-N-C catalyst is a potential good candidate to be used as catalytic material for DMFC cathode, in alternative to Pt. The performance in a H2/O2 PEMFC was tested as well, showing a power density of 105mWcm−2 at 60°C.

Performance of thermally modified wood during 14 years of outdoor exposure

The long-term outdoor performance of thermally modified timber (TMT) from four different industrial heat treatment processes was investigated. Graveyard tests (in-ground exposure, use class (UC) 4) and horizontal double layer tests (above ground, UC 3.2) with and without artificial shading were performed. Results from field tests after 14 years of exposure are compared with results from short-term laboratory tests with pure cultures of wood-destroying basidiomycetes and terrestrial microcosms (TMC). The thermally modified material used in the study was: Plato wood (Norway spruce, Picea abies, NL), Thermowood (Scots pine, Pinus sylvestris, FI), New Option Wood (NOW, Maritime pine, Pinus maritima, F), and oil-heat treated (OHT) wood (Scots pine, DE). In addition, Scots pine sapwood and heartwood, Douglas fir (Pseudotsuga menziesii), Sessile oak (Quercus petraea), and CCB treated Scots pine sapwood (0.7 and 2.8% CCB) were examined as control and reference materials. Based on results from laboratory standard tests with brown and white rot causing basidiomycetes all thermally modified materials were classified as durable to slightly durable (durability class (DC) 2–4). In TMC tests with unsterile soil against soft rot and other soil-inhabiting micro-organisms all TMT were classified as durable (DC 2). Consequently, all TMT showed remarkably increased durability compared to the untreated controls (DC 5) and reference species (DC 3–5). In contrast, according to the results of the graveyard tests all four TMTs were classified less durable (DC 4) as well as Douglas fir and Sessile oak. Also exposure above ground in horizontal double layers led to a significantly worse durability compared to the one calculated on the basis of lab test results: Plato, Thermowood, and NOW were classified as ‘less durable’ (DC 4), OHT performed significantly better. Since not all specimens had failed its durability was preliminarily classified as ‘very durable’ (DC 1). On the basis of 14 years outdoor testing under different exposure conditions durability of four industrially produced TMTs turned out to be clearly less than lab test results indicated. Neither in-ground nor above ground performance met the expectations based on testing with basidiomycete cultures and TMCs. Therefore, short-term durability test methods need improvements regarding their predictive capability for modified wood. In summary, the use of TMT in ground as well as under severe above ground conditions cannot be recommended based on the findings from this field test study.

Performance evaluation of an air-breathing high-temperature proton exchange membrane fuel cell

The air-breathing proton exchange membrane fuel cell (PEMFC) is of great interest in mobile power sources because of its simple system design and low parasitic power consumption. Different from previous low-temperature air-breathing PEMFCs, a high-temperature PEMFC with a phosphoric acid doped polybenzimidazole (PBI) membrane as the polymer electrolyte is designed and investigated under air-breathing conditions. The preliminary results show that a peak power density of 220.5mWcm−2 at 200°C can be achieved without employing any water managements, which is comparable to those with conventional Nafion® membranes operated at low temperatures. In addition, it is found that with the present cell design, the limiting current density arising from the oxygen transfer limitation is around 700mAcm−2 even at 200°C. The short-term durability test at 200mAcm−2 and 180°C reveals that all the cells exhibit a gradual decrease in the voltage along with a rise in the internal resistance. The degradation rate of continuous operation is around 58.32μVh−1, which is much smaller than those of start/stop cycling operations.