Maximum Power Density Of Cell Research Articles

Three-dimensional multiphase simulation of a partially narrowed flow field configuration for a high-performance polymer electrolyte membrane fuel cell

A partially narrowed flow field configuration has been recently proposed and applied to the Toyota new Mirai to enhance the mass diffusion and water drainage inside a polymer electrolyte membrane (PEM) fuel cell, thereby elevating the output cell performance. This study performs a 3D multiphase fuel cell simulation to comprehensively investigate the underlying mechanism of mass diffusion and water drainage behavior inside a partially narrowed flow field configuration. Moreover, various structural parameters with respect to the partially narrowed flow field configuration are examined to achieve further enhanced output cell performance. The results indicate that the partially narrowed flow field configuration yields a relatively high pressure drop inside the channel, thereby boosting convective mass diffusion within the electrodes. The total narrowed section length, width and length and arrangement of the individual narrowed section significantly affect the mass diffusion, water drainage behavior, pressure drop and output cell performance. By optimizing the structural parameters of the partially narrowed flow field configuration, substantial improvements in mass diffusion and water drainage inside the fuel cell are achieved. The fuel cell maximum power density increases by 7.5% compared with the traditional straight flow field with a relatively low pressure drop.

Batch synthesis of high activity and durability carbon supported platinum catalysts for oxygen reduction reaction using a new facile continuous microwave pipeline technology

Traditional synthesis methodologies for fuel cell catalyst production involve long reactions and uncontrollable reaction processes. Synthesis methods for the production of catalysts typically have difficulties to achieve catalysts materials with consistency, high activity, and durability. In this study, a fast, simple, and suitable continuous pipeline microwave method for catalyst mass production was developed, with the carbon carrier being treated at different temperatures simultaneously. The method herein developed resulted in carbon-supported platinum (Pt) catalysts with high activity and high durability. In addition, the half-wave potential of the catalyst exceeded 0.9 V, the electrochemical active surface area reached 85.7 m2-gPt−1, and the mass specific activity reached 171.1 mA-mg−1. Remarkably, after 30,000 cycles of Pt attenuation tests and 30,000 cycles of carbon carrier attenuation tests, the retention rate of the annealed carbon carrier catalyst reached 80 %. As a membrane electrode, the catalyst generated a single cell maximum power density of 1.4 W-cm−2, and the Pt content reached 0.286 gPt-kW−1. The work provides an effective and practical method for the mass production of high-performance and high-durability catalysts, which guiding significance for mass production of catalysts.

Atmospheric plasma spraying to fabricate metal‐supported solid oxide fuel cells with open‐channel porous metal support

AbstractMetal‐supported solid oxide fuel cells (MS‐SOFCs) have been fabricated by applying phase‐inversion tape‐casting and atmospheric plasma spraying (APS). The effect of the binder amount of the phase‐inversion slurries on the microstructure development of the 430L stainless steel metal support was investigated. The pore structures, the viscosity of the slurry, porosity and permeability of the as‐prepared metal supports are significantly influenced by the amount of the binder. NiO–scandia‐stabilized zirconia (ScSZ) anode, ScSZ electrolyte and La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) cathode layers were consecutively deposited on the metal support with an ideal microstructure by APS process. The effect of plasma power of the APS on the microstructure of the electrolyte and cathode was investigated. A dense electrolyte layer and a porous cathode layer were successfully obtained at 40 and 6 kW of the APS plasma power, respectively. MS‐SOFCs, with a cell configuration of 430L/Ni‐ScSZ/ScSZ/LSCF, achieved a maximum cell power density of 1079 mW cm−2 at 700°C using humidified H2 as fuel and ambient air as oxidant. The corresponding ohmic resistance and total resistance of MS‐SOFCs was 0.14 and 0.32 Ω cm2, respectively. This work demonstrates the feasibility of fabricating high‐performance MS‐SOFCs with economical and scalable techniques.

Performance and thermal stresses in functionally graded anode-supported honeycomb solid-oxide fuel cells

Enhancing the performance of anode supported honeycomb solid-oxide fuel cells via operating at higher temperatures is of great interest. However, working at a higher temperature leads to a significant rise in thermal stresses over the allowable limit. Thus, in the current study, functionally graded electrodes are considered to avoid cell failure due to higher thermal stresses. To assess the cell performance and thermal stress distribution, a theoretical investigation of a solid-oxide fuel cell with a honeycomb configuration using functionally graded electrode compositions is conducted through a comprehensive 3D model. The developed model includes the charge transport, mass and momentum transport, energy conservation, electrochemical reaction kinetics, and elastic stress. The model is numerically simulated and validated with the available experimental data. Results indicate that using functionally graded electrodes with grading index m = 1 significantly improves the fuel cell's performance, with an improvement in power density reaching around 60%. In addition, the most beneficial improvement is to reduce thermal stresses at elevated temperatures, for which the maximum value of equivalent stress is reduced to 85% less than the conventional electrode at a temperature of 1150 °C. Accordingly, the fuel cell's maximum power density can be obtained by operating at elevated temperatures with safe thermal stresses. These improvements are particularly attractive for applications requiring compact, reliable, and high-power devices based on fuel cell technology.

Characteristics of Oxygen Electrode Supported Reversible Solid Oxide Cells

Oxygen-electrode-supported solid oxide cells (OESCs) have potential advantages over fuel-electrode-supported cells, including reduced fuel-electrode concentration polarization, better oxygen electrode current collection, and flexibility in the fuel electrode choice. However, there are serious drawbacks including the difficulty of co-firing the oxygen electrode and electrolyte, and oxygen electrode concentration polarization. This paper explores the characteristics of OESCs with La0.8Sr0.2MnO3−δ -Zr0.92Y0.16O2−δ (LSM-YSZ) electrode-support enhanced by SrTi0.3Fe0.6Co0.1O3−δ (STFC) infiltration, thin YSZ electrolyte, and SrTi0.3Fe0.7O3−δ (STF) fuel electrodes. The STFC infiltration increases fuel cell maximum power density by >1.5 times and electrolysis current density (at 1.3 V) by >2 times. Cell performance in pure oxygen is compared to that in air, exploring a possible reversible solid oxide cell system configuration where oxygen produced during electrolysis is stored and subsequently used during fuel cell operation. The fuel cell maximum power density is increased from 0.88 W cm−2 in air to 1.37 W cm−2 in oxygen, with limiting current increased from 1.7 to >5.6 A cm−2; the electrolysis performance is essentially unchanged, probably because the electrode air becomes enriched with oxygen during electrolysis.

Effect of SrTi0.3Fe0.6Co0.1O3 Infiltration on the Performance of LSM-YSZ Cathode Supported Solid Oxide Fuel Cells with Sr(Ti,Fe)O3 Anodes

The Sr(TiFe)O3 (STF) composite is one of alternatives to Ni-base cermet anode for solid oxide fuel cells (SOFCs) that can provide improved tolerance to redox cycling, fuel impurities, and hydrocarbon fuels. However, the porous STF-based anodes are usually difficult applied on the conventional anode supported cells with thin electrolyte membrane since co-sintering with electrolyte is limited to these materials. Here, we report our recent findings in exploring the La0.8Sr0.2MnO3-Zr0.92Y0.16O2 (LSM-YSZ) cathode supported SOFCs with thin YSZ electrolyte membrane suitable for application of STF-based fuel electrodes. In order to improve the cell performance, here we report results on the infiltration of SrTi0.3Fe0.6Co0.1O3 (STFC), a recently reported high performance mixed ionically and electronically conducting, into LSM-YSZ to improve its electrochemical performance at intermediate temperatures. The infltrated STFC enhances LSM-YSZ and cell performance, typically yielding in an increase in fuel cell maximum power density by a factor > 1.5 times.

Electrochemical performance and stability of SrTi0.3Fe0.6Co0.1O3-δ infiltrated La0.8Sr0.2MnO3[sbnd]Zr0.92Y0.16O2-δ oxygen electrodes for intermediate-temperature solid oxide electrochemical cells

The La0.8Sr0.2MnO3Zr0.92Y0.16O2-δ (LSM-YSZ) composite is the most widely used oxygen electrode for solid oxide electrochemical cells (SOCs). However, operating temperatures >700 °C are required for good performance since oxygen reactions are limitied to three-phase boundaries (TPBs) because of poor ionic conductivity of LSM. Furthermore, LSM-YSZ electrodes typically delaminate during electrolysis operation leading to cell degradation. One strategy to improve SOCs with LSM-YSZ electrodes is to infiltrate a mixed ionically and electronically conducting (MIEC) material that promotes oxygen exchange. However, infiltrated materials have a nano-scale structure that may not be stable under SOC operating temperatures. Here, we report results on the infiltration of SrTi0.3Fe0.6Co0.1O3-δ (STFC), a recently reported high performance MIEC, into LSM-YSZ to improve its electrochemical performance and stability at intermediate temperatures. The infiltrated STFC enhances LSM-YSZ and cell performance, typically yielding a decrease in electrode polarization resistance by a factor >3 times, resulting in an increase in fuel cell maximum power density and electrolysis current density (at 1.3 V) by a factor > 2 times. Perhaps more significantly, the infiltrated electrodes show good performance stability, with suppression of electrode delamination during electrolysis and no evidence of coarsening or segregation induced degradation.

Maximizing SOFC performance through optimal parameters identification by modern optimization algorithms

A modern optimization algorithm is used for maximizing the performance of solid oxide fuel cell. At first, the cell is modeled using Artificial Neural Networks based on the experimental data sets. Then, a robust, simple, and quick optimization algorithm named radial movement optimizer is used for determining the optimal operating parameters of the cell. The cell parameters used in the optimization process are anode support layer thickness, anode porosity, electrolyte thickness, and cathode interlayer thickness. The optimization obtained results are compared with the previous optimized experimental results and those obtained using genetic algorithm. Two sets of the parameters' constraints are considered during the optimization process. In the first set, the resulting optimal cell parameters are 0.5 mm, 76%, 20 μm, and 62.26 μm for anode thickness, anode porosity, electrolyte thickness, and cathode thickness respectively. Under this condition, the cell maximum power density is 1.8 W/cm2, 2.25 W/cm2 and 2.72 W/cm2 for experimentally, genetic algorithm and the proposed strategy, respectively. This implies that using the proposed method increases the power density by 33.8% and 17.28% over the experimental and genetic, respectively. In the second set, the proposed optimizer increases the maximum power by 28.85% compared with genetic optimizer.

PdCu/C anode catalysts for the alkaline ascorbate fuel cell

In this work, PdCu/C catalysts are used to increase the power output of an alkaline ascorbate fuel cell using an alkaline anion exchange membrane. The alkaline ascorbate fuel cell produces significantly more power than a direct ascorbic acid fuel cell using an acidic cation exchange membrane. However, that alkaline ascorbate fuel cell employs Pd catalyst at the anode. Since addition of Cu to a Pd catalyst results in higher oxidation rates for polyalcohol oxidation in alkaline media, we add Cu to this Pd catalyst to study its impact on ascorbate oxidation in alkaline media. The ascorbate fuel cell maximum power density increases from 53 mW cm−2 when Pd/C is used at the anode to 89 mW cm−2 when Pd28Cu72/C is used. Per mass of Pd, the Pd/C anode produces only 32 mW mg−1 while the Pd28Cu72/C anode produces 194 mW mg−1. Electrochemical analysis of various PdCu/C catalysts shows that the current density after oxidation at −0.4 V for 1 h increases with the addition of greater quantities of Cu to the Pd catalyst, from 0.111 mA cm−2 on Pd/C to 0.757 mA cm−2 on Pd11Cu89/C. This increase in catalytic efficiency when Cu is added to the Pd catalyst is attributed to a combination of the electronic and bifunctional effects.

Performance of La0.8Sr0.2Ga0.8Mg0.2O3-based SOFCs with atmospheric plasma sprayed La-doped CeO2 buffer layer

Ce0.6La0.4O2 (LDC) is a promising buffer layer for preventing chemical reactions between a doped-LaGaO3 electrolyte and Ni-based anode in intermediate-temperature solid oxide fuel cells (SOFCs). In the present work, first, the chemical compatibility between La0.8Sr0.2Ga0.8Mg0.2O3 (LSGM) powders and LDC powders is evaluated. Subsequently, an LDC buffer layer is prepared via atmospheric plasma spraying (APS) at different deposition temperatures using powders that have particle sizes larger than 30 μm. The effects of deposition temperature on the microstructure and ionic conductivity are investigated. Cells with an optimized APS LDC interlayer between the NiO containing anode and LSGM electrolyte are tested with humidified H2 as fuel and ambient air as the oxidation. At 750 °C, the maximum power density of cells with the APS LDC interlayer is 460 mW/cm2. In addition, a stability test of ∼400 h at 650 °C under a constant current density of 250 mW/cm2 is carried out, and the cell with the optimized APS LDC interlayer is stable. Therefore, APS is a viable alternative approach for fabricating an LDC interlayer for SOFCs using the LSGM electrolyte.

Half-Cell Study of La and Ca Doped Strontium Titanates Anode for Direct Methane Solid Oxide Fuel Cell

Solid oxide fuel cell (SOFC) has been providing high conversion efficiency of chemical energy to electricity without any pollution. One of the major advantages of SOFC over other fuel cell is use of direct natural gas at high temperature without any external reformer. Conventional Ni-yttria stabilized zirconia (YSZ) composite anode provides excellent catalytic property, current collection and stability for H2 oxidation but it is not tolerant towards sulphur poisoning and also accelerates coke deposition in presence of hydrocarbon fuels. It necessitates the use of alternate anode for direct hydrocarbon SOFC. In the present work, attempts have been made to apply A-site deficient La and Ca doped SrTiO3 (LSCTA-) as potential anode for direct methane SOFC. Electrolyte supported half-cells with LSCTA- anode backbone have been tested in H2 and humidified CH4 fuel. Low catalytic activity of LSCTA- towards electro oxidation of fuel is significantly improves in presence of metallic catalyst. 6% CeO2 loading in LSCTA- backbone improves the performance of the cell in H2 as well as in humidified CH4 at 800 °C. It has been observed that coke deposition did not degrade the anode active surface even after 6 h of exposure of CH4 at the elevated temperature of 800 °C. 4% Ni infiltration in 6%CeO2-LSCTA- enhances the performance from 131 mW cm-2 to 200 mw cm-2 at 800 °C in H2. In humidified CH4 environment, cell having 4% Ni-6% CeO2-LSCTA- anode shows lesser performance (140 mw cm-2 Power density) due to sluggish methane oxidation reaction but provided enhanced power density (216 mw cm-2) once H2 is again fed after 6 h cell operation in humidified CH4. i-V/ i-P analysis of half-cell shown in fig. 1 explains the performance in H2 as well as in CH4 at 800 °C. Maximum power density of cell is 200 mW cm-2 (554 mA cm-2) at 1 h of operation in H2, which increases up to 216 mW cm-2 (578 mA cm-2) in H2 after 6h of cell operation in humidified CH4. In humidified CH4 exposure, maximum power density of cell is 89 mW cm-2 (285 mA cm-2) at 1 h of operation, which increases up to 140 mW cm-2 (409 mA cm-2) at 6 h of operation. The performance of the cell is reasonably good as results presented here correspond to a cell having thick electrolyte (300 μm). The cells are found to be structurally robust even after 12 h of accelerated testing. LSCTA-is a potential anode backbone material for direct methane SOFC and could be an excellent anode for other hydrocarbons. Key Words: A-site deficient SrTiO3, Direct Methane SOFC, LSCTA- anode, half-cell study. Figure 1

Copper-doped lanthanum ferrites for symmetric SOFCs

Structure stability and electrical conductivity of La1-xSrxFe0.8Cu0.2O3-δ with x = 0.2, 0.4 were investigated both in air and in hydrogen to explore their potential applications as symmetric electrodes for solid oxide fuel cells. La0.8Sr0.2Ga0.8Mg0.2O3-δ (LSGM) electrolyte supported symmetric fuel cells were fabricated and tested in air/hydrogen ambient in 650–800 °C temperature range achieving a maximum power density of 162 mW cm−2. To improve the cell performance, a composite electrode (70 wt% La1-xSrxFe0.8Cu0.2O3-δ −30 wt% Gd0.2Ce0.8O3-δ) was successfully evaluated both at the anode and the cathode sides decreasing the cell polarization resistance to 0.454 Ω cm2 at 800 °C and reaching a single cell maximum power density of 294 mW cm−2.

Kinematics and trajectory analysis of the fixed abrasive lapping process in machining of interdigitated micro-channels on bipolar plates

The fixed abrasive lapping process is presented to investigate its ability and accuracy in machining of interdigitated micro-channels on bipolar plates that are used in the proton exchange membrane fuel cell. A kinematical equation to describing the relative movement between the fixed abrasive lapping plate and workpiece is developed and used to numerically simulate the trajectories of a single diamond abrasive and fixed diamond abrasives with 17 different arraying forms, respectively. It is shown that the lapping trajectory can be superposed periodically when the rotation ratio is a rational number. By assessing the uniformity of lapping trajectories and opening ratio of the bipolar plate the optimized rotation ratio is obtained which is 1:1, and the best arraying form of the fixed diamond abrasives on the lapping plate has been obtained as well that is the arraying form of C4. Then, a set of fixed abrasive lapping tests were conducted to explore its ability in machining of interdigitated micro-channels on bipolar plates. It is found that larger material removal rate can be achieved by employing bigger lapping pressure and higher rotation speed for both copper and stainless steel samples considered in this study. The maximum cell power density is found to be about 165mWcm−2 by testing the performance of a single micro fuel cell with a bipolar plate characterized by interdigitated micro-channels that shows a good cell performance.

The co-doping effect of Sm and In on ceria for electrolyte application in IT-SOFC

Sm, In co-doped ceria Ce0.80Sm0.20-xInxO1.90 (SDCI) series (x = 0, 0.075, 0.10, 0.15) are fabricated, aiming to evaluate the doping effect of In on the electrolyte performance of Ce0.80Sm0.2O1.90 (SDC). XRD is employed to characterize the structure of the Sm, In co-doped ceria. The symmetrical cells and single cells consisting of Sm, In co-doped ceria is fabricated and analyzed via electrochemical impedance spectra and I–V diagram. The proportion of Ce3+ and Ce4+ in SDCI is investigated by XPS. The results of multiple analysis approaches indicate that the electrical performance of Sm, In co-doping ceria is enhanced. The maximum power density of cells fabricated by SDCI is improved on condition that the concentration of In is below 10 mol%. Sm, In co-doping is proved to be a promising avenue to improve the ionic conductivity and catalytic activity of ceria.

Cobalt-free double perovskite cathode GdBaFeNiO5+δ and electrochemical performance improvement by Ce0.8Sm0.2O1.9 impregnation for intermediate-temperature solid oxide fuel cells

To improve thermal expansion compatibility and structural stability of the cobalt-based double perovskite cathode such as GdBaCo2O5+δ, a cobalt-free double perovskite GdBaFeNiO5+δ (GBFN) is investigated as a potential cathode for intermediate-temperature solid oxide fuel cells based on Ce0.8Sm0.2O1.9 (SDC) electrolyte. The structure, properties and improved electrochemical performance of the GBFN material are reported in detail. The GBFN has a tetragonal structure at room temperature. Mixed valence states of Fe3+/Fe4+ and Ni2+/Ni3+ coexist in the GBFN material. The absence of spin state in Ni2+ contributes to a reduction in the thermal expansion coefficient (TEC). The average TEC of the GBFN sample is 14.7×10−6K−1 between 30 and 1000°C in air. The GBFN undergoes a transition from semiconductor to metallically conductive behaviors at 400°C. The substitution of Fe and Ni for Co significantly improves the structural stability of the GBFN. The GBFN material exhibits a good chemical compatibility with SDC electrolyte at temperatures below 1000°C. The activity and performance of the GBFN cathode are further improved by the impregnation of nano-sized SDC particles: the polarization resistance is decreased by ∼14.2 times and the maximum power density of cell is increased by ∼1.9 times. The reason of electrochemical performance improvement is also discussed.

Effect of PEG additive on anode microstructure and cell performance of anode-supported MT-SOFCs fabricated by phase inversion method

Anode-supported micro-tubular solid oxide fuel cells (MT-SOFCs) have been fabricated by phase inversion method. For the anode support preparation, N-methyl-2-pyrrolidone (NMP), polyethersulfone (PESf) and poly ethylene glycol (PEG) were applied as solvent, polymer binder and additive, respectively. The effect of molecular weight and amount of PEG additive on the thermodynamics of the casting solutions was characterized by measuring the coagulation value. Viscosity of the casting slurries was also measured and the influence of PEG additive on viscosity was studied and discussed. The presence of PEG in the casting slurry can significantly influence the final anode support microstructure. Based on the microstructure result and the measured gas permeation value, two anode supports were selected for cell fabrication. For cell with the anode support fabricated using slurry with PEG additive, a maximum cell power density of 704 mW cm−2 is obtained at 750 °C with humidified hydrogen as fuel and ambient air as oxidant; cell fabricated without any PEG additive shows the peak cell power density of 331 mW cm−2. The relationship between anode microstructure and cell performance was discussed.

Characteristics of electrolyte supported micro-tubular solid oxide fuel cells with GDC-ScSZ bilayer electrolyte

In this study, a gadolinia-doped ceria (GDC)-supported micro tubular SOFC (T-SOFC) was fabricated using extrusion and dip-coating techniques (Cell A). The effects of inserting a scandium-stabilized zirconia (ScSZ) layer as an electron blocking layer between the GDC layer and the GDC-Ni anode layer were also explored (Cell B). The microstructures and electrochemical performances of Cell A and Cell B were investigated and compared. The layer thicknesses of the GDC and ScSZ bi-layer electrolytes were approximately 285 μm and 8 μm respectively. With the inserted ScSZ layer, both the ohmic resistance and the polarization resistance significantly increased at all the operating temperatures. The increase in the ohmic resistance of Cell B was predominantly due to the interfacial resistance, while the substantial escalation in the polarization resistance was mainly because of the low bulk oxygen diffusion process in the ScSZ layer and the smaller charge transfer processes occurring at the interfaces. The OCV of Cell B showed a slight decrease from 1.06 to 0.98 V and that of Cell A experienced an obvious decline from 0.92 to 0.76 V as the temperature rose from 650 to 800 °C. The ScSZ layer of Cell B successfully inhibited the OCV loss caused by the electronic conduction in GDC. The maximum power densities (MPDs) of Cell A at 650, 700, 750, and 800 °C were 0.20, 0.27, 0.33, and 0.36 Wcm−2, and those of Cell B 0.16, 0.23, 0.32, and 0.42 Wcm−2. The MPD of Cell B was improved at temperatures above 750 °C but remained inferior to that of Cell A below 750 °C. This is due to the fact that, as operating temperature increased above 750 °C, the benefit of the higher OCV in Cell B surpassed the deficiency of the higher cell resistance, thereby leading to a higher MPD.

Hydrogen Production on an Ethanol Dehydrogenation Reactor Coupled to a Conventional PEMFC

On board hydrogen storage has become a key factor for the technical viability of fuel cell driven electric or hybrid vehicles. In this work we present results of a system which comprises an ethanol dehydrogenation catalytic unit coupled to a conventional proton exchange membrane fuel cell (PEMFC). Ethanol is first dehydrogenated over a Cu/ZrO2 catalyst bed, and then the gas effluent is trapped in a simple cold condenser enabling a gas current rich in H2 to feed a PEMFC. Chronoamperometry (at a cell potential of 700 mV) showed apparent stability of the cell performance at about 300 mA cm-2 (with H2 produced from ethanol reaction) whilst at 550 mA cm-2 with pure H2. Maximum cell power density of our integrated system achieved almost 70% of the performance of the cell powered with pure H2.

Effects of stack orientation and vibration on the performance of PEM fuel cell

SUMMARY An experimental study is carried out to investigate effects of stack orientation and vibration on the performance of Proton Exchange Membrane (PEM) fuel cell. A 25-cm2 single cell with serpentine anode and straight cathode flow channels is used. The hydrogen flow rate, cathode air temperature, and relative humidity are kept constant at 60 smL/min, 20 °C and 80%, respectively, whereas the cathode air flow rate values are 220, 440, and 660 smL/min as well as free breathing case. An orientation and vibration mechanisms are designed to facilitate different values orientation positions and vibration amplitude and frequency of the stack. The results show that stack orientation and vibration have significant effects on the performance of PEM fuel cell. Based on the results obtained from this study, it can be concluded that optimum positions of cell orientation are 30° and 90° at low and high values of cathode air flow rate, respectively. Also, an improvement in the performance of the fuel cell is achieved when the stack is vibrated with low values of amplitude and frequency. Each of cell maximum power density and maximum hydrogen utilization decreases with increasing each of amplitude and frequency of stack vibration. Copyright © 2014 John Wiley & Sons, Ltd.

Investigation of A-site deficient Ba0.9Co0.7Fe0.2Nb0.1O3−δ cathode for proton conducting electrolyte based solid oxide fuel cells

A novel cathode material for proton conducting electrolyte based solid oxide fuel cells (SOFCs) of A-site deficient Ba0.9Co0.7Fe0.2Nb0.1O3−δ (BCFN) has been synthesized and characterized. The A-site deficient BCFN has demonstrated a thermal expansion coefficient (TEC) similar to that of BaZr0.1Ce0.7Y0.2O3−δ (BZCY) electrolyte, enhanced oxygen reduction activity and chemical stability. The application of BCFN in proton-conducting electrolyte-based SOFCs has been investigated, and the SOFCs with Ni-BZCY|BZCY|BCFN configuration demonstrate maximum cell power outputs of 180, 240 and 300 mW cm−2 at 600, 650 and 700 °C, respectively. The cell polarization resistance is as low as 0.951, 0.387 and 0.201 Ω cm2 under open circuit voltage (OCV) at 600, 650 and 700 °C, respectively. The cell maximum power density increases from 300 to 356 mW cm−2 at 700 °C after over 118 h operating under a constant current of 300 mA cm−2.