Excellent Fuel Cell Performance Research Articles

A high-performing and stable Pr0.25Nd0.25Ca0.5MnO3-δ cathode for protonic ceramic fuel cells

This study proposes a new Pr0.25Nd0.25Ca0.5MnO3-δ (PNCM) cathode material for protonic ceramic fuel cells (PCFCs). As demonstrated by first-principles calculations, the Ca-doping strategy can promote oxygen vacancy formation and accelerate the oxygen reduction reaction (ORR) compared to the conventional Sr-doping method. Additional experiments reveal the doping of Ca can enhance the proton and oxygen diffusion abilities compared with the traditional Sr-doped material. Consequently, the PCFC with single-phase PNCM cathode produces a high peak power density of 1232 mW cm-2 at 700 °C, which is significantly greater than the cell with Sr-doped cathode, which only produces 749 mW cm-2 under the same testing conditions. The PNCM cathode inherits the excellent stability of manganate cathodes, allowing the fuel cell to exhibit good stability under operational conditions. PNCM is a new and promising cathode material for PCFCs due to its excellent fuel cell performance and stability.

Phosphorylated poly(ethylene-co-vinyl alcohol) doping for enhanced proton conductivity and mechanical properties of side chain–type sulfonated poly(aryl ether ketone) proton-exchange membranes

Phosphorylated poly (ethylene-co-vinyl alcohol) (PEVOH) was synthesized and blended with side chain–type sulfonated poly (aryl ether ketone) (SPAEK) to prepare SPAEK proton-exchange membranes with improved physicochemical and electrochemical properties. The results indicate that PEVOH doping helps improve the mechanical properties and proton conductivity of the membranes. The addition of PEVOH not only enhances proton transport but also provides proton transport channels for the membranes at a high temperature and low humidity, leading to excellent fuel cell performance and low ohmic resistance. The interaction between sulfonic acid and phosphonic acid side chain groups leads to the excellent nano-phase separation under microscopic morphology. This forms a large hydrogen bonding network between the acidic and amphoteric groups, which facilitates proton transport at low relative humidities.

Proton-conducting γ-MnO2 based heterostructure composite electrolyte for protonic ceramic fuel cells

Proton-conducting electrolyte materials are essential for the development of high-performance protonic ceramic fuel cells (PCFCs). This work investigates the proton conduction property of a γ-MnO2 based heterostructure electrolyte composing with gadolinium-doped ceria (GDC). The electrochemical proton injection into the γ-MnO2-GDC composite electrolyte is thoroughly studied using various characterization techniques, including infrared (IR) and Raman spectroscopy, and EIS with distribution of relaxation times (DRT) analysis. The optimized γ-MnO2-GDC heterostructure composite exhibits an ionic conductivity of 0.2 S cm−1 at 520 °C during fuel cell operation and proton conduction dominating the ion conduction is confirmed by proton filtering cell. Excellent fuel cell performance with a maximum power density of 896 mW cm−2 at 520 °C has been demonstrated. The work highlights the potential of the γ-MnO2 based heterostructure composite as a proton-conducting electrolyte material for advanced PCFCs, offering new prospects for the development of cost-effective and efficient energy conversion technologies.

Rapidly Direct Laser 3D Printing of High-Performance Protonic Ceramic Fuel Cells

Fuel cells with a dense ionic conducting electrolyte layer sandwiched between two porous electrode layers are one of the most efficient fuel-to-electricity energy conversion devices. Their reversible operation can also efficiently electrolyze water to hydrogen, reduce carbon dioxide to fuels, synthesize ammonia, upgrade fuels, and store energy on large scales. Compared with the popular low-temperature (~80 oC) proton exchange/polymer electrolyte membrane fuel cells and the high-temperature (700-1000 oC) oxygen ion-conducting solid oxide fuel cells (SOFCs), initially used in electric vehicles, auxiliary powers, power plants, and hydrogen electrolyzers, the rising star of protonic ceramic fuel cells (PCFCs) based on proton conducting oxide electrolytes offers excellent suitability for operating at 400-700 oC, the optimum temperature range for electrochemical energy devices, enabling extensive superiorities (high efficiency and performance, long thermal and chemical stabilities, flexible fuels, and cost-effective compatible materials) compared to their counterparts. In recent ten years, many high-performance PCFCs have been reported. However, most performances were achieved using small-area button cells (<0.5cm2) fabricated using spin coating, drop coating, manual brushing, and screen printing of electrolytes on the dry-pressed anode supports, followed by co-firing. There are challenges to transferring the excellent microstructures and materials chemistries/properties obtained from small-area cells to large-area cells and stacks. Furthermore, the decrease in cell component layer thickness for high volumetric cell performance and the requirement for more efficient, faster, and more cost-effective manufacturing motivated the advanced manufacturing of PCFCs.This work will focus on the direct laser 3D printing (DL3DP) of PCFCs performed at Clemson University. The DL3DP integrated 3D printing (microextrusion and ultrasonic spraying) and laser processing (drying, sintering, and machining), allowing for manufacturing PCFC components, single cells, and stacks with the desired microstructures and geometries irrelevant to the area. The DL3DP could rapidly and cost-effectively manufacture PCFCs without conventional long-term furnace processing. The processing speed could be 2 orders of magnitude faster than the conventional tape-casting and furnace co-firing method. The achieved cells and stacks showed excellent fuel cell performance and less dependence on the effective area. The cells showed peak power densities 1.6-2.6 times that of the conventionally processed samples. The stacks demonstrated a peak power of 7 W and constant power outputs of 0.5-3.1 W for 110-260 hours. This DL3DP can be expanded to manufacturing other heterogeneous ceramics for energy conversion and storage devices. Figure 1

Protonic Ceramic Electrochemical Cells with Dry Reforming of Methane for Electricity Generation, Chemicals Manufacturing, and Greenhouse Gas Mitigation

The massive exploration and utilization of fossil fuels for power generation and chemicals manufacturing have contributed to worldwide economic growth. However, these activities lead to significant greenhouse gas (GHG) emissions, which primarily include CO2 and CH4. The technologies, which intensify power generation with chemicals production from CO2 and CH4, will reduce the carbon footprint and address associated challenges. Dry reforming of methane (DRM, CH4 + CO2→ 2CO + 2H2) in electrochemical devices, which converts both CO2 and CH4 to a mixture of CO and H2 (i.e., syngas), and electricity, could be leveraged to achieve simultaneous power generation, chemicals manufacturing, and GHG mitigation. In this talk, we will present our novel protonic ceramic electrochemical cells (PCECs) for achieving this objective. The current PCECs with internal DRM suffer from poor performance, high operating temperature, and short durable operation, which is mainly ascribed to the lack of highly active and coking tolerant DRM catalysts that could be chemically and physically compatible with PCECs. This talk with present an oxide-supported in-situ exsolved Ni-Ru catalyst, which has been carefully designed and computationally validated as a highly active and coking-tolerant DRM catalyst. This DRM catalyst significantly enhances the catalytic activity and coking tolerance, which consequently lowers the operating temperatures of PCECs, with excellent fuel cell performance durability demonstrated. An exceptional peak power density of 0.94, 0.65, and 0.30 W cm-2 has been attained at 650 °C, 600 °C, and 550 °C, respectively, setting a record of PCECs for DRM.

Transition-Metal and Nitrogen-Doped Carbon Nanotube/Graphene Composites as Cathode Catalysts for Anion-Exchange Membrane Fuel Cells

Transition-metal and nitrogen-doped graphene-like material and carbon nanotube (M-N-Gra/CNT) composites are prepared, characterized, and used as cathode catalysts in anion-exchange membrane fuel cells (AEMFCs). Melamine as a nitrogen source and cheap iron and cobalt salts as metal precursors are used for doping via high-temperature pyrolysis. The success of doping is proven by several physicochemical analysis methods, and the catalyst materials possess rather similar textural properties. The initial assessment of the oxygen reduction reaction activity using the rotating disk electrode method shows that Fe-N-Gra/CNT, Co-N-Gra/CNT, and CoFe-N-Gra/CNT materials have very similar electrocatalytic performances in alkaline media as well as excellent short-term stability but a different yield of HO2– formation. The M-N-Gra/CNT materials as cathode catalysts together with the Aemion+ reinforced anion-exchange membrane exhibit very good AEMFC performance, especially CoFe-N-Gra/CNT, comparable to that of Pt/C, reaching a peak power density of 638 mW cm–2. Such an excellent fuel cell performance of the M-N-Gra/CNT catalyst materials is attributed to the presence of M–Nx sites, carbon-encapsulated transition-metal nanoparticles, and feasible nitrogen-containing moieties.

Designing Gadolinium-doped ceria electrolyte for low temperature electrochemical energy conversion

Reducing the operational temperature of solid oxide fuel cells (SOFC) is vital to improving their durability and lifetime. However, a traditional SOFC suffers from high ohmic and polarization losses at low temperatures, leading to poor performance. Gadolinium-doped ceria is the best ionic conductor for SOFC at lower temperatures. The present work envisages the GDC as an electrolyte for applying low-temperature solid oxide fuel cells (LT-SOFCs). So, in this regard, herein, GDC is synthesized through a wet chemical co-precipitation technique as a functional electrolyte layer fixed between two symmetrical porous electrodes NCAL (Ni0.8Co0.15Al0.05LiO2). Due to the improved surface properties of the synthesized GDC, particles perform better than commercially available GDC. The synthesized GDC electrolyte shows an impressive fuel cell performance of 569 mW/cm2 and a high ionic conductivity of 0.1 S/cm at a shallow temperature of 450 °C. Moreover, the fuel cell device utilizing the synthesized GDC remained stable for 150 h of operation at a high current density of 110 mA/cm2 at 450 °C. The high conduction mechanism has been proposed in detail. The results show that excellent fuel cell performance, high ionic conductivity, and better stability can be achieved at exceptionally low enough temperatures. Also, the proposed work suggests that new electrolytes can be designed for developing advanced low-temperature fuel cell technology.

Designing Composite BaCe0.4Zr0.4Y0.1Yb0.1O3-δ-Sm0.2Ce0.8O2-δ Heterostructure Electrolyte for Low-Temperature Ceramic Fuel Cell (LT-CFCs)

In recent years, tuning perovskite and fluorite-based materials and modifying them to ionic conductors has been an interesting but challenging topic for advanced low-temperature ceramic fuel cells (LT-CFCs). In this regard, we prepared a new composite heterostructure, BaCe0.4Zr0.4Y0.1Yb0.1O3-Sm0.2Ce0.8O2 (BCZYYb-SDC), and evaluated it as an electrolyte to realize the fuel cell reaction. The developed electrolyte could be a hybrid ionic conductor, possess a very small ohmic area-specific resistance, and exhibit excellent fuel cell performance of over 1.0 W/cm2 along with higher OCV of more than 1.1 V at a low operating temperature of 550 °C. The attained performance and ionic conductivity are specially accredited to constructing the heterostructure of BCZYYb-SDC. Moreover, various spectroscopy and microscopic analysis methods have been used to investigate the ions’ transportation, while on the other hand suppressing the electronic conduction. The developed composite heterostructure proposes and suggests new insight to design new electrolytes for LT-CFCs.

Achieving over 1,000 mW cm−2 Power Density Based on Locally High‐Density Cross‐Linked Polybenzimidazole Membrane Containing Pillar[5]arene Bearing Multiple Alkyl Bromide as a Cross‐Linker

AbstractCross‐linking is widely accepted as an effective method to improve the mechanical strength and durability of phosphoric acid (PA) doped polybenzimidazole (PBI) membranes. However, the cross‐linked membranes generally exhibit compromised overall performance since their compact network structures decrease the free volumes of membranes, leading to poor proton conductivity. In this study, a locally high‐density cross‐linked polybenzimidazole network based on pillar[5]arene bearing multiple alkyl bromide is constructed for the first time to achieve high proton conductivity, desired mechanical properties, and excellent fuel cell performance. The pillar[5]arene‐cross‐linked network considerably enhances the mechanical strength of membrane (14.6 MPa), particularly with high PA uptake, and provides loose PBI chain segment packing to retain PA (315.9%). Surprisingly, the pillar[5]arene‐cross‐linked PBI membrane displays a high‐power density of 1,084.1 mW cm−2 at 180 °C and 0.6 mg cm−2 Pt loading without backpressure and humidification, that is the highest value reported in cross‐linked membranes for high‐temperature proton exchange membrane fuel cells.

Interfacial active-sites p-n heterojunction SFT-WO3 for enhanced fuel cell performance at 400–500 °C

The enhanced ionic conductivity of electrolytes in fuel cells could be optimized by inhibiting the e-conduction, constructing heterostructure, built-in electric field (BIEF), and creating a more active site within the lattice. High ionic conductivity and suppression of e-conductivity are of paramount significance in the field of a fuel cell. One possible approach is synthesizing the type-II heterojunction to achieve high ionic conductivity and enhanced fuel cell performance. In this perspective, we have synthesized p-n heterojunction SFT (SrFe0.3Ti0.8O3)-WO3 via compositing the individual SFT (p-type) and WO3 (n-type) semiconductors. The obtained SFT-WO3 exhibit impressive fuel cell performance of 875 mW/cm2, high ionic conductivity of 0.2 S/cm, and better OCV 1.04 V at a low operating temperature of 520 °C. The excellent fuel cell performance and high ionic conductivity can be interpreted as the synergistic effect between SFT-WO3 heterojunction and BIEF. Various characterizations (XRD, SEM, HR-TEM, UV–visible, UPS, and XPS) confirmed heterojunction formation between SFT and WO3. Furthermore, the energy band structure and valence band deviation of the SFT-WO3 junction were approved. Also, the theoretical calculation (DFT calculation) has been performed to support the experimental results. Our finding reveals that the synthesized heterostructure SFT-WO3 is a competent and promising electrolyte indicating the insight of developing low-temperature-based electrolytes for fuel cell technology.

Molecular dynamics simulations and experimental studies of the perfluorosulfonic acid-based composite membranes containing sulfonated graphene oxide for fuel cell applications

In this investigation, to understand the impact on glass transition temperature (Tg) and increase the mechanical properties (elastic and shear modulus), proton conductivity, and single-cell performance, sulfonic acid (-SO3H) functionalized graphene oxide (SGO) was introduced in the perfluorosulfonic acid (PFSA) membranes (Nafion). We conducted atomistic molecular dynamics simulations of fully dry and hydrated PFSA membranes at various hydration levels and SGO loading. The Tg of PFSA polymer composite membranes was increasing with the rising loading percentage of SGO because of the strong connection between the SGO and the PFSA polymer chains in the fully dry states. In addition, the strong antiplasticization effect of water resulted in a further increase of the Tg of hydrated Nafion/SGO-4 composite membranes. The elastic and shear modulus of the Nafion/SGO (Nafion is trade name PFSA membranes) composites increased significantly with SGO loading because of the strong interfacial interaction between SGO and PFSA polymer chains. PFSA membranes loaded with SGO exhibited significant improvement in proton conductivity up to 0.167 S/cm at 90% relative humidity (RH), 95˚C, 2 wt% SGO loading, which is 1.51 times of recast Nafion membrane. In addition, PFSA composite membrane showed excellent fuel cell performance in terms of maximum power density up to 0.97 W/cm2 at 100% RH, 80 ˚C, 2 wt% SGO loading, which is ∼1.3 times of recast Nafion membrane at similar test conditions because of the hygroscopic nature of SGO, the creation of interconnected proton-conducting channels, and the reduction of fuel permeability through the prepared composite membranes.

An effective strategy to enhance dimensional-mechanical stability of phosphoric acid doped polybenzimidazole membranes by introducing in situ grown covalent organic frameworks

Poor dimensional-mechanical stability and severe acid leakage have been the crucial issues restraining the practical applications of phosphoric acid-doped polybenzimidazole (PA−PBI) as high-temperature proton exchange membranes (HT-PEMs). In view of their robust, ordered, and tunable porous structures, chemically stable covalent organic frameworks (COFs) show great promise to enhance the performance of PA-doped PBI membrane. In this work, the in situ synthesized COF sheets are introduced to the PBIs for the first time and form a unique composite structure. The composite structure comprising soft PBIs matrix and rigid COF sheets can obviously improve dimensional-mechanical stability of the membranes under high acid doping level. Importantly, the rigid COF sheets help to construct proton transport channel in the membrane, resulting in high proton conductivity and excellent fuel cell performance. Among them, the 40%–COF–OPBI membrane shows the best overall performance, such as excellent proton conductivity (177.7 mS cm−1), desirable mechanical tensile strength (12.1 MPa), and high power density (774.7 mW cm−2) at 160 °C without humidification in H2/O2 fuel cell tests. These results suggest that introducing COFs to PBI is an effective strategy for fabricating high-performance proton exchange membranes for fuel cell applications.

Modification of sulfonated poly (etherether ketone) composite polymer electrolyte membranes with 2D molybdenum disulfide nanosheet-coated carbon nanotubes for direct methanol fuel cell application

Fabrication of novel proton exchange membrane (PEM) is crucial to the development of direct methanol fuel cells (DMFCs). Here, molybdenum disulfide (MoS2) nanosheets were anchored onto carbon nanotubes (CNTs) via a facile in-situ growth method, and then a series of composite PEMs were fabricated via embedding MoS2-coated CNTs (MoS2@CNTs) in the sulfonated polyether ether ketone (SPEEK) matrix. The coating of MoS2 nanosheets improved the dispersibility and compatibility with the polymer matrix and enhanced the mechanical properties of the composite membranes. Owing to the unique one-dimensional structure of CNTs and the hydrophilic MoS2 coating, channel-like ion transport pathways (water channels) could be constructed, which would enhance the ionic conductivity of the composite membrane. It is worth noting that the incorporation of 1 wt% MoS2@CNTs at 80 °C resulted in 1.7-fold proton conductivity relative to pristine SPEEK membrane, and substantially decreased its methanol permeability. As a result, the SPEEK/MoS2-1 composite membrane exhibited excellent fuel cell performance with a high peak power density of 98.5 mW cm−2 at 70 °C, which was 73.7% higher than that of the SPEEK membrane and Nafion-115 membrane. Finally, the durability test further validated the potential of SPEEK/MoS2@CNTs composite membrane to be used as an alternative for Nafion membrane.

Well-designed polyphenylene PEMs with high proton conductivity and chemical and mechanical durability for fuel cells

Sulfonated polyphenylene ionomers containing trifluoromethyl substituents exhibit high proton conductivity and excellent fuel cell performance and durability under severe conditions.

Evaluation of LaxSr1−xZnyFe1−yO3−δ(x= 0.54, 0.8,y= 0.2, 0.4) as a promising cobalt free composite cathode for SOFCs

Cobalt free composite cathode materials with excellent fuel cell performance and thermal stability are reported as promising candidates for intermediate temperature solid oxide fuel cells (IT-SOFCs).

Constructing novel cross-linked polybenzimidazole network for high-performance high-temperature proton exchange membrane

Compared with linear polybenzimidazole (PBI) membranes, cross-linked phosphoric acid (PA)-PBI membranes with superior mechanical strength have greater potential for application in high-temperature proton exchange membrane fuel cells (HT-PEMFCs). However, performances of conventional cross-linked membranes are usually limited by densely cross-linked network, and reduced concentration of proton-conductive imidazole units. Therefore, it still remains a big challenge to fabricate high-performance cross-linked PA-PBI membranes. Herein, we build covalently cross-linked PBI network using commercially available 2,6-bis(hydroxymethyl)-4-methylphenol (BHMP) as cross-linking agent through a well-established film-forming process. The optimized covalently cross-linked network can combine high mechanical properties, desired proton conductivity as well as excellent fuel cell performance, owing to a loose but tough cross-linked molecular structure and existence of favorable additional hydroxyl for proton transport. Especially, the covalently cross-linked membrane with BHMP content of 1% display a high proton conductivity of 168.4 mS cm−1 and a good power density of 597.5 mW cm−2 at 160 °C without humidification, outperforming the pristine OPBI membrane. Additionally, in long-term durability test, the voltage decay of cross-linked membrane is low (0.0212 mV h−1) at current density of 200 mA cm−2, suggesting an excellent membrane stability.

The effect of –NH− on quaternized polybenzimidazole anion exchange membranes for alkaline fuel cells

To investigate the effect of –NH− in polybenzimidazole (PBI) on the properties of PBI anion exchange membranes (AEMs), naphthalene based polybenzimidazole (NPBI) was partially grafted with cationic side chains to afford NPBI-QAx membrane, and then reacted with bromobutane to achieve fully grafting polymer namely NPBI-QAx-By. Surprisingly, after attaching n-butyl on the benzimidazole groups in NPBI backbones completely, the fully grafting polymer NPBI-QA55-B45 showed much higher hydroxide conductivity, achieving 31.7 mS/cm at 20 °C. This value was tenfold compared with that of NPBI-QA55 (2.96 mS/cm at 20 °C) membrane having similar IEC value without N-substitute. It was assumed that ionic interaction occurred between positively charged fixed cations and negatively charged benzimidazolide rings when the NPBI-QAx membranes were immersed in 1 M NaOH. FT-IR and XPS analysis on NPBI-QAx membranes confirmed that ionic interaction between positively charged fixed cations and negatively charged benzimidazolide rings occurred when treated in 1 M NaOH, while no obvious ionic interaction was observed when immersion in 1 M NaHCO3. However, the ionic interaction resulted in excellent stability of the membrane (NPBI-QA55) with –NH− groups, e.g. no obvious chemical structure degradation after alkaline stability test at 80 °C in 5 M NaOH for 760 h, while the NPBI-QA55-B45 membrane suffered from chemical degradations via ring opening reaction of NPBI backbones and nucleophilic substitution of pendant QA cations as confirmed by 1H NMR. Moreover, improved conductivity resulted in excellent fuel cell performance for NPBI-QA55-B45 membrane and the peak power density was about 260.1 mW/cm2. However, no fuel cell performance was obtained for the NPBI-QA55 membrane due to the formation of ionic interaction.

Highly Conductive Polybenzimidazole Membranes at Low Phosphoric Acid Uptake with Excellent Fuel Cell Performances by Constructing Long-Range Continuous Proton Transport Channels Using a Metal-Organic Framework (UIO-66).

Phosphoric acid (PA)-doped polybenzimidazoles generally require high PA doping levels to achieve high conductivity as high-temperature proton exchange membranes. However, high PA doping levels result in a significant decrease in the mechanical properties of and PA leaching from the membranes. Herein, a Zr-based metal-organic framework material (UIO-66) was introduced into poly[2,2'-(p-oxydiphenylene)-5,5'-benzimidazole] (OPBI) membranes. The composite membranes exhibited long-range continuous proton transport channels when the mass ratio of UIO-66 to OPBI was ≥30 wt %. The long-range continuous proton transport channels endowed the composite membranes with high proton conductivity at low PA doping levels. When the doping of UIO-66 in the OPBI membrane reached 40 wt %, the membrane exhibited the highest proton conductivity (0.092 S cm-1, at 160 °C) at a low PA uptake (73.25%), while the conductivity of the pristine OPBI membrane was 0.050 S cm-1 with a high PA uptake (217.43%). Additionally, in the oxyhydrogen fuel cell test, 40%UIO-66@OPBI membranes exhibited excellent fuel cell performance with a peak power density of 583 mW cm-2 at 160 °C, which is 50% higher than that of the pristine OPBI membrane (374 mW cm-2). A single cell based on 40%UIO-66@OPBI also demonstrated good durability and could remain at about 600 mV after 500 h of operation under a constant load of 200 mA cm-2.

The effect of polymer backbones and cation functional groups on properties of anion exchange membranes for fuel cells

The anion conductive polymers based on the aryl ether-free polyaromatics (poly[(fluorene alkylene)-co-(biphenyl alkylene)] (PFBA), poly(fluorene alkylene) (PFA)) and aryl ether-containing polyaromatics (poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)) having various cation groups (quaternary ammonium (QA) or bulky imidazolium (MIm or PIm)) were designed and prepared to investigate the effect of polymer backbones and cation functional groups on the properties of anion exchange membranes (AEMs) in fuel cells. The PFBA AEM having bulky imidazolium group showed good mechanical properties while the PPO AEM with the same cation break into the pieces. The alkalinity of the bulky imidazoliums have determined to be weaker than that of the typical quaternary ammonium by the simulation. Thus, the high hydroxide conductivities of the AEMs based on the quaternary ammonium group have been observed. Although the alkaline stability testing in 2 mol L−1 NaOH at 80 °C indicated the AEMs based on the PFBA backbone are much more alkaline stable than that of the AEMs from PPO backbone, the PFA-QA having typical quaternary ammonium showed significant degradation signals in 2 mol L−1 NaOD CD3OD/D2O solution at 80 °C for 15 days while PFA-MIm with bulky imidazolium groups showed no degradation signal at the same testing condition. The single H2/O2 fuel cell testing at 60 °C suggested the polymer backbone and cations displayed significant effect on the fuel cell performance. The highest peak power density of 610 mW cm−2 was achieved for PFBA-QA-0.4 which is approximate twice as high as that of the PPO-QA-0.4 (351 mW cm−2) and also the PFBA-MIm-0.4 having bulky imidazolium (32 mW cm−2). The device durability test indicates that the voltage of PFBA-QA-0.4 membrane could be maintained above 0.7 V at 200 mA cm−2 for 74 h. These results suggested that the aryl ether-free polymer backbone would be a good choice for the high performance AEM designation, and the AEMs having alkaline stable bulky imidazoliums needed to be further investigated in detail to achieve excellent fuel cell performance.

Structural and electrochemical studies of microwave sintered nanocomposite electrolytes for solid oxide fuel cells

In this study, a nanocomposite electrolyte is synthesized using a microwave sintering technique, providing an alternative method and improving the conventional sintering technique. In this paper, samarium doped ceria (SDC) materials are synthesized by the co-precipitation method using carbonates as precipitating agents. The precursor of SDC-carbonate is sintered in a microwave (MW) oven and conventionally heated in a digital furnace at 900 °C. X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques are applied for structural studies. For electrochemical characterization, four probe conductivity and fuel cell performances are completed. The materials prepared using MW improved the densification and exhibited excellent sintering during compared to the conventional method of preparation for the same material. Excellent fuel cell performance (0.65 W cm−2) is achieved with microwave sintering. This method of sintering proves that the microwave process can save time and energy when compared to conventional sintering. This method can provide significant economic benefits compared to conventional sintered materials for applications in fuel cell technology.