Cathode Material For Fuel Cells Research Articles

Zeolite Framework-Anchored Carbon-Doped White Graphene as Antipoisoning Cathode Materials for Proton-Exchange Membrane Fuel Cells

Zeolite Framework-Anchored Carbon-Doped White Graphene as Antipoisoning Cathode Materials for Proton-Exchange Membrane Fuel Cells

Structural and Electrochemical Characterisation of NBZFO Cobalt-Free Cathode Material for Intermediate-Temperature Solid Oxide Fuel Cells: An Experimental Investigation

Compared to other energy-generating technologies and energy conversion devices, intermediate-temperature solid oxide fuel cells (IT-SOFCs) have gained significant attention from energy experts due to its high energy density, moderate operating temperature (600–800°C), low emissions and reliability. Enhancing the performance of IT-SOFCs requires suitable and excellent cathode materials. Thus, a perovskite-type Nd0.5Ba0.5Zr0.8Fe0.2O3+δ (NBZFO) material was synthesised via traditional solid-state reaction technique and analysed as a potential cathode material for IT-SOFCs. Analysis of X-ray diffraction data (XRD) revealed a single-phase perovskite material that crystallises in cubic space group (pm-3m). The thermal and electrochemical properties were analysed with the aid of thermogravimetric analysis (TGA) and electrochemical impedance spectroscopy (EIS). NBZFO has an electrical conductivity in air of 80 S cm−1 at 400°C and a polarisation resistance (Rp) of 0.106 Ω cm2 at 800°C. TGA reveals a slight loss in weight of about 0.58%, thereby suggesting a highly stable cathode material for IT-SOFC. Electrochemical investigation shows that NBZFO has good electronic and ionic conductivity and excellent oxygen stichometry. Further studies are required to understand the effects of varying B-site composition of the cathode material.

Sr0.7R0.3CoO3-δ (R = Gd, Eu, and Sm) Perovskites Infiltrated with Pd: Enhancing the Performance as Cathode Materials in Solid Oxide Fuel Cells

Sr_0.7R_0.3CoO_3-δ (R = Gd, Eu, and Sm) Perovskites Infiltrated with Pd: Enhancing the Performance as Cathode Materials in Solid Oxide Fuel Cells

Ca-Doping Cobalt-Free Double Perovskite Oxide as a Cathode Material for Intermediate-Temperature Solid Oxide Fuel Cell.

Mixed oxygen ion and electron-conducting materials are viable cathodes for solid oxide fuel cells due to their excellent oxygen transport kinetics and mixed electrical conductivity, which ensure highly efficient operation at low and medium temperatures. However, iron-based double perovskite oxides usually exhibit poor electrocatalytic activity due to low electron and oxygen ion conductivity. In this paper, Ca is doped in PrBaFe2O5+δ A-site to improve the electrochemical performance of PrBaFe2O5+δ. Results show that replacing Pr with Ca does not change the crystal structure, and the Ca doping effectively increases the adsorbed oxygen content and accelerates the migration and diffusion rate of O2- to the electrolyte|cathode interface. The polarization resistance of the symmetric cell PC0.15BF|CGO|PC0.15BF is 0.033 Ω·cm2 at 800 °C, which is about 56% lower than that of PBF, confirming the enhancement of the mixed conduction of oxygen ions and electrons. In addition, the anode-supported single cell has a peak power density of 512 mW·cm-2 at 800 °C.

Monitoring the Morphological Changes of Skeleton-PtCo Electrocatalyst during PEMFC Start-Up/Shut-Down probed by in situ WAXS and SAXS.

Advanced in situ analyses are indispensable for comprehending the catalyst aging mechanisms of Pt-based PEM fuel cell cathode materials, particularly during accelerated stress tests (ASTs). In this study, a combination of in situ small-angle and wide-angle X-ray scattering (SAXS & WAXS) techniques were employed to establish correlations between structural parameters (crystal phase, quantity, and size) of a highly active skeleton-PtCo (sk-PtCo) catalyst and their degradation cycles within the potential range of the start-up/shut-down (SUSD) conditions. Despite the complex case of the sk-PtCo catalyst comprising two distinct fcc alloy phases, our complementary techniques enabled in situ monitoring of structural changes in each crystal phase in detail. Remarkably, the in situ WAXS measurements uncover two primary catalyst aging processes, namely the cobalt depletion (regime I) followed by the crystallite growth via Ostwald ripening and/or particle coalescence (regime II). Additionally, in situ SAXS data reveal a continuous size growth over the AST. The Pt-enriched shell thickening based on the Co depletion within the first 100 SUSD cycles and particle growth induced by additional potential cycles were also collaborated by ex situ STEM-EELS. Overall, our work shows a comprehensive aging model for the sk-PtCo catalyst probed by complementary in situ WAXS and SAXS techniques.

Electrochemical properties of B-site non-stoichiometric layered perovskite SmBa0.5Sr0.5CoxO5+d (x=1.9–2.1) cathodes for IT-SOFC

In this study, layered perovskites were synthesized using a non-stoichiometric synthesis strategy that allowed the variation of the amount of Co substitution in the basic composition of SmBa0.5Sr0.5Co2O5+d (SBSCO), used as a cathode material for Intermediate Temperature-operating Solid Oxide Fuel Cells (IT-SOFCs).SmBa0.5Sr0.5CoxO5+d (x = 1.9–2.1, SBSCO-1.9–2.1), B-site non-stoichiometric layered perovskites, were analyzed to characterize the electrical and electrochemical properties with respect to the Co substitution. Among them, SmBa0.5Sr0.5Co2.05O5+d (SBSCO-2.05) exhibited the best electrical and electrochemical properties with an ASR of 0.082 Ωcm2 and an electrical conductivity of 268.42 S/cm at 700 °C (measured in air within a series of measurements of increasing measuring temperature). Therefore, B-site non-stoichiometric perovskite compositions with increased Co substitution on their B sites represent a key strategy for achieving high performance cathodes compared to cathodes with stoichiometric compositions.

Promising Cathode Materials for Solid Oxide Fuel Cells

Promising Cathode Materials for Solid Oxide Fuel Cells

Advancements in Perovskite-Based Cathode Materials for Solid Oxide Fuel Cells: A Comprehensive Review.

The high-temperature solid oxide fuel cells (SOFCs) are the most efficient and green conversion technology for electricity generation from hydrogen-based fuel as compared to conventional thermal power plants. Many efforts have been made to reduce the high operating temperature (>800 °C) to intermediate/low operating temperature (400 °C<T<800 °C) in SOFCs in order to extend their life span, thermal compatibility, cost-effectiveness, and ease of fabrication. However, the major challenges in developing cathode materials for low/intermediate temperature SOFCs include structural stability, catalytic activity for oxygen adsorption and reduction, and tolerance against contaminants such as chromium, boron, and sulfur. This research aims to provide an updated review of the perovskite-based state-of-the-art cathode materials LaSrMnO3 (LSM) and LaSrCOFeO3 (LSCF), as well as the recent trending Ruddlesden-Popper phase (RP) and double perovskite-structured materials SOFCs technology. Our review highlights various strategies such as surface modification, codoping, infiltration/impregnation, and composites with fluorite phases to address the challenges related to LSM/LSCF-based electrode materials and improve their electrocatalytic activity. Moreover, this study also offers insight into the electrochemical performance of the double perovskite oxides and Ruddlesden-Popper phase materials as cathodes for SOFCs.

The effects of sintering temperature and current contacting layer on the performance of lanthanum nickelate electrodes in Solid Oxide Fuel Cells

The Ruddlesden-Popper phase La2NiO4+δ (LNO214) has received a significant level of research attention with respect to its employment as a Solid Oxide Fuel Cell cathode material. However, it is known that there are many factors that are capable of influencing the performance of this phase when utilised in this role. One such factor that can impact on electrode behaviour is the choice of sintering temperature. In this paper, a study of this effect is detailed. This is achieved via the use of both symmetrical and single cell testing configurations, with additional investigation provided by ex-situ analysis. It is shown that a sizeable improvement in electrode performance can be achieved via an increase in sintering temperature. This is despite observations on the reactivity between LNO214 and the contact electrolyte material Ce0.9Gd0.1O2-δ. Further, it is also demonstrated that the addition of a noble metal contacting layer can dramatically improve the performance of an LNO214 electrode. In comparison, the impact of a contacting layer on a state-of-the-art La0.6Sr0.4Co0.2Fe0.8O3-δ composition is shown to be relatively minor. This has implications towards SOFC testing methodologies given the widespread employment of noble metal contacting pastes.

Cathode Materials for Microbial Fuel Cells

The most important problems of today are meeting the increasing energy needs and avoiding environmental pollution caused by fossil resources usage for energy production. In addition, the decrease in usable water in the world has become a threat to human health and the population. Microbial fuel cells (MFC) have become more interesting in recent years because of their potential to solve these three important problems. Organic and inorganic contents in wastewater can be seen as potential energy sources. MFCs are the only systems that can convert the chemical energy in the organic and inorganic content of wastewater into electricity. While this transformation is realized, the process of cleaning the wastewater can be done. Reducing the costs of these systems is the most important parameter to accelerate the use of the system. In particular, studies on reducing the cost and increasing the efficiency of the catalysts used in the cathode compartment where the oxygen reduction reaction takes place are predominant. In this study, cathode materials used in MFCs will be examined and alternative materials will be discussed.

Research Progress of Cathode Materials for Graphene-based Fuel Cells

Graphite is the most widely used cathode material for commercial lithium-ion batteries at present, and the increasing market demand puts forward higher requirements for lithium storage performance of graphite cathode materials. Graphene is a kind of cathode material with great development potential, and its lithium storage performance is influenced by many factors such as structural characteristics, oxygen-containing functional groups and impurity atoms, which leads to complex lithium storage behavior and mechanism. When the polymer with lithium storage activity is compounded with graphene as cathode material, the lithium storage performance is affected by the reversibility of polymer redox and the composite structure. In this article, the working principle of Li-lon and the lithium intercalation mechanism of graphite are introduced, and the research status and progress of graphite cathode materials in surface modification and structural regulation in recent years are emphatically reviewed.

La1.5Nd0.3Pr0.2NiO4.16: A New Cathode Material for IT-Solid Oxide Fuel Cells

La1.5Nd0.3Pr0.2NiO4.16: A New Cathode Material for IT-Solid Oxide Fuel Cells

Fe-based double perovskite with Zn doping for enhanced electrochemical performance as intermediate-temperature solid oxide fuel cell cathode material.

This study aims to investigate the implications of transition-metal Zn doping at the B-site on the crystal structure, average thermal expansion coefficient (TEC), electrocatalytic activity, and electrochemical performance of LaBaFe2O5+δ by preparing LaBaFe2-xZnxO5+δ (x = 0, 0.05, 0.1, 0.15, 0.2, LBFZx). The X-ray diffraction (XRD) results show that Zn2+ doping does not change the crystal structure, the unit cell volume increases, and the lattice expands. The X-ray photoelectron spectroscopy (XPS) and mineral titration results show that the oxygen vacancy concentration and Fe4+ content gradually increase with the increase in doping amount. TEC decreases with the increase in Zn2+ doping amount, and the TEC of LBFZ0.2 is 11.4 × 10-6 K-1 at 30-750 °C. The conductivity has the best value of 103 S cm-1 at the doping amount of x = 0.1. The scanning electron microscopy (SEM) images demonstrate that the electrolyte CGO(Gd0.1Ce0.9O1.95) becomes denser after high-temperature calcination, and the cathode material is well attached to the electrolyte. The electrochemical impedance analysis shows that Zn2+ doping at the B-site can reduce the (Rp) polarization resistance, and the Rp value of the symmetric cell with LaBaFe1.8Zn0.2O5+δ as cathode at 800 °C is 0.014 Ω cm2. The peak power density (PPD) value of the anode-supported single cell is 453 mW cm-2, which shows excellent electrochemical performance.

Cathode Materials for Microbial Fuel Cells

Günümüzün en önemli sorunları arasında artan enerji ihtiyacını karşılamak ve fosil kaynakların enerji üretimi için kullanımından kaynaklanan çevre kirliliğinin önlenmesi yer almaktadır. Ayrıca, dünyadaki kullanılabilir sudaki azalma insan sağlığı ve nüfusu için bir tehdit haline gelmiştir. Mikrobiyolojik yakıt hücreleri (MYH) bu üç önemli sorunu çözme potansiyeli sebebiyle son yıllarda daha ilgi çekici bir konu haline gelmiştir. Atık sulardaki organik ve inorganik içerikler potansiyel bir enerji kaynağı olarak görülebilir. MYH'ler, atık suyun organik ve inorganik içeriğindeki kimyasal enerjiyi elektriğe dönüştürebilen tek sistemdir. Bu dönüşüm gerçekleştirilirken, atık suyun temizlenmesi işlemi yapılabilir. Bu sistemlerin maliyetlerini azaltmak, sistemin kullanımını hızlandırmak için en önemli parametredir. Son zamanlarda özellikle, oksijen indirgeme reaksiyonunun gerçekleştiği katot bölmesinde kullanılan katalizörlerin maliyetinin düşürülmesi ve verimliliğinin arttırılması üzerine yapılan araştırmalar hız kazanmıştır. Bu çalışmada, MYH 'lerde kullanılan katot malzemeleri incelenecek ve alternatif malzemeler tartışılacaktır.

In-situ segregation of A-site defect (La0.6Sr0.4)0.90Co0.2Fe0.8O3-δ to form a high-performance solid oxide fuel cell cathode material with heterostructure

As a potential cathode material for solid oxide fuel cells, the commercial application of La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) has to face the challenges in insufficient oxygen reduction reaction (ORR) activity, segregation of Sr element, and CO2 poisoning. Therefore, the effect of A-site non-stoichiometry on the electrochemical performance of (LS)1-xCFs (x = −0.05, 0, 0.05, 0.10, 0.15) from the aspect of microstructure/elemental surface chemical environment evolution is investigated in this paper. The results show that (LS)0.90CF has the best ORR activity and the highest electrochemical performance. The excellent electrochemical performance is attributed to the (LS)0.90CF/Co2FeO4/CoFe2O4-type heterostructure, formed by in-situ segregation induced by A-site defects, which improves the surface oxygen diffusion coefficient and chemical bulk diffusion coefficient of the cathode. At the same time, the A-site defect can effectively inhibit the segregation of Sr element in (LS)0.90CF, thereby improving the tolerance of CO2. At 800 °C, the area-specific resistance (ASR) of (LS)0.90CF (0.023 Ω cm2) is 66.7% lower than that of LSCF (0.069 Ω cm2), and the peak power density (1.57 Wcm−2) is 1.8 times higher than that of LSCF (0.87 Wcm−2). Therefore, perovskite A-site defect-induced B-site segregation to form heterostructures provides an effective strategy for the preparation of high-performance cathode materials.

Enhanced Performance of LSCF as a Cathode Material for Solid Oxide Fuel Cell By Using Gamma Radiation

Enhanced Performance of LSCF as a Cathode Material for Solid Oxide Fuel Cell By Using Gamma Radiation

Zeolitic Imidazolate Framework-Derived Copper Single Atom Anchored on Nitrogen-Doped Porous Carbon as a Highly Efficient Electrocatalyst for the Oxygen Reduction Reaction toward Zn–Air Battery

Here, copper single atoms anchored on nitrogen-doped porous carbon (Cu-N/PC) derived from zeolitic imidazolate frameworks (ZIFs) as a highly efficient electrocatalyst for the oxygen reduction reaction (ORR) were demonstrated. Specifically, as a nitrogen-rich bridge molecule, tubular g-C3N4 (TCN) can trap free Cu ions through the electrostatic interaction in the initial stage. Then, Cu-ion-doped TCN can be used to regulate the content of copper and nitrogen doping, the electronic structure, as well as the specific surface area and pore diameter of Cu-N/PC. As a result, the high density of exposed Cu-N4 active sites and the high level of porosity in Cu-N/PC may significantly enhance the ORR activity with a more positive onset potential (E0 = 0.97 V versus reversible hydrogen electrode (RHE)) and half-wave potential (E1/2 = 0.88 V) than the commercially available Pt/C catalyst (E0 = 0.94 V, E1/2 = 0.85 V). Furthermore, the homemade Zn–air battery (ZAB) equipped with Cu-N/PC is able to deliver excellent performance, including a peak power density of 215.8 mW cm–2 and a specific capacity of 704.9 mAh g–1 based on Zn anode, outperforming the Pt/C catalyst. The finding highlights a new guideline for constructing Cu-N/PC catalyst with a well-designed structure and superior property for advanced fuel cell cathode materials.

A Review of X-ray Photoelectron Spectroscopy Technique to Analyze the Stability and Degradation Mechanism of Solid Oxide Fuel Cell Cathode Materials.

Nondestructive characterization of solid oxide fuel cell (SOFC) materials has drawn attention owing to the advances in instrumentation that enable in situ characterization during high-temperature cell operation. X-ray photoelectron spectroscopy (XPS) is widely used to investigate the surface of SOFC cathode materials because of its excellent chemical specificity and surface sensitivity. The XPS can be used to analyze the elemental composition and oxidation state of cathode layers from the surface to a depth of approximately 5–10 nm. Any change in the chemical state of the SOFC cathode at the surface affects the migration of oxygen ions to the cathode/electrolyte interface via the cathode layer and causes performance degradation. The objective of this article is to provide a comprehensive review of the adoption of XPS for the characterization of SOFC cathode materials to understand its degradation mechanism in absolute terms. The use of XPS to confirm the chemical stability at the interface and the enrichment of cations on the surface is reviewed. Finally, the strategies adopted to improve the structural stability and electrochemical performance of the LSCF cathode are also discussed.

Improvement of La0.8Sr0.2MnO3-δ Cathode Material for Solid Oxide Fuel Cells by Addition of YFe0.5Co0.5O3.

The high efficiency of solid oxide fuel cells with La0.8Sr0.2MnO3−δ (LSM) cathodes working in the range of 800–1000 °C, rapidly decreases below 800 °C. The goal of this study is to improve the properties of LSM cathodes working in the range of 500–800 °C by the addition of YFe0.5Co0.5O3 (YFC). Monophasic YFC is synthesized and sintered at 950 °C. Composite cathodes are prepared on Ce0.8Sm0.2O1.9 electrolyte disks using pastes containing YFC and LSM powders mixed in 0:1, 1:19, and 1:1 weight ratios denoted LSM, LSM1, and LSM1, respectively. X-ray diffraction patterns of tested composites reveal the presence of pure perovskite phases in samples sintered at 950 °C and the presence of Sr4Fe4O11, YMnO3, and La0.775Sr0.225MnO3.047 phases in samples sintered at 1100 °C. Electrochemical impedance spectroscopy reveals that polarization resistance increases from LSM1, by LSM, to LSM2. Differences in polarization resistance increase with decreasing operating temperatures because activation energy rises in the same order and equals to 1.33, 1.34, and 1.58 eV for LSM1, LSM, and LSM2, respectively. The lower polarization resistance of LSM1 electrodes is caused by the lower resistance associated with the charge transfer process.

Impact of the Synthesis Method on Electrochemical Performance of La0.5Sr0.5MnO3 Perovskite Oxide as a Cathode Material in Alkaline Fuel Cells

Impact of the Synthesis Method on Electrochemical Performance of La0.5Sr0.5MnO3 Perovskite Oxide as a Cathode Material in Alkaline Fuel Cells