Electrode Materials For Fuel Cells Research Articles

In situ TEM Pyrolysis of Conductive 2D Coordination Polymers for Improved Application as Solid Acid Fuel Cell Electrode Materials

In situ TEM Pyrolysis of Conductive 2D Coordination Polymers for Improved Application as Solid Acid Fuel Cell Electrode Materials

Synthesis and Physicochemical Characterization of Solid Oxide Electrolyte and Electrode Materials for Medium-Temperature Fuel Cells

Synthesis and Physicochemical Characterization of Solid Oxide Electrolyte and Electrode Materials for Medium-Temperature Fuel Cells

(Digital Presentation) Ni-Doped PrBaFe2O5+ δ As Symmetrical Electrode for Solid Oxide Cells

The development of new redox stable electrode materials for Solid Oxide Cells (SOFs) have attracted great attention in recent years, since finding suitable compositions to operate efficiently in both fuel cell and electrolyzer modes is crucial for their wide commercialization [1]. For this reason, research on new doping strategies [2] and advanced deposition techniques [3] for symmetrical electrode materials have significantly increased with the aim of simplifying cell fabrication and extending cell durability. In this sense, double perovskites are gaining great interest due to their excellent electrical properties and high redox and long-term stability in different atmospheres [4].In this study, the double-perovskite (PrBa)0.95Fe2O5+δ (PBF) is proposed as symmetrical electrode for SOCs [5]. Two different strategies are implemented: on the one hand, Ni-doping in order to improve the electrical properties under reducing atmosphere and, on the other hand, the preparation of nanostructured electrodes in one-step by spray-pyrolysis deposition. A thorough characterization of the material is performed regarding its crystal structure, microstructure and electrochemical properties in both oxidizing and reducing atmospheres.With that purpose, PBF and (PrBa)0.95Fe2-xNixO5+ δ (PBFNx) powders are prepared by the freeze-drying precursor method. XRD patterns show the formation of a single perovskite-type phase in both air and H2 atmospheres, without the presence of any secondary phases. As for conductivity tests, they reveal increased values for the Ni-doped material over the pristine PBF material in air and 5% H2 at 600 ºC. These materials were thereafter screen-printed onto La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM) electrolyte and calcined at 1100 ºC for 1h to ensure adequate adhesion to the electrolyte.Alternatively, spray-pyrolysis deposition method is employed to infiltrate PBFNx, with a 0.02 M precursor solution of the corresponding nitrate salts, into a porous Ce0.9Gd0.1O1.95 (CGO) layer previously fixed onto LSGM electrolyte (PBFNx-CGO). SEM images reveal that the screen-printed PBFNx has a thickness of 30 µm and a particle size of around 1 µm, while the same composition deposited by spray-pyrolysis shows a nanometric particle size and it is well-infiltrated in the 10 µm-thick CGO layer (Figure 1a). These electrode microstructures are maintained after ongoing a reduction process, where exsolved Ni particles are observed on the surface.The impedance spectra show lower polarization resistance (Rp) values for PBFNx with respect to PBF, i.e. 0.47 and 0.62 Ω cm2 at 650 ºC in air, respectively. But most significantly, further Rp reduction is observed for PBFNx-CGO prepared by spray-pyrolysis, values as low as 0.17 Ω cm2 at 650 ºC in air (Figure 1b). In reducing atmosphere, the PBFNx-CGO electrode also has lower Rp values (0.23 Ω cm2 at 650 ºC) when compared to the pristine PBF (0.52 Ω cm2 at 650 ºC).All in all, the nanostructured Ni-doped PBF electrodes exhibit high redox stability and low polarization resistance values under both oxidizing and reducing atmospheres, demonstrating their potential application as symmetrical electrodes for SOCs. These findings show that the optimization of the electrode composition but mostly its microstructure is key when developing new electrode materials for solid oxide cells.This research is supported by Ministerio de Ciencia, Innovación y Universidades through the RTI2018-093735-B-I00 and UMA18-FEDERJA-033 projects (Spain), and the University of Malaga through the B1-2021_03 project.[1] J. Zamudio-García, L. Caizán-Juanarena, J.M. Porras-Vázquez, E.R. Losilla, D. Marrero-López, A review on recent advances and trends in symmetrical electrodes for solid oxide cells, J. Power Sources. 520 (2022). https://doi.org/10.1016/j.jpowsour.2021.230852.[2] T. Su, Y. Li, Y. Yang, Z. Xu, N. Shi, Y. Wan, Y. Xie, D. Huan, S. Xue, C. Xia, Effect of tungsten doping on strontium ferrite electrode for symmetrical solid oxide electrochemical cell, Int. J. Hydrogen Energy. 45 (2020) 23401–23410.[3] Y. Kwon, S. Kang, J. Bae, Development of a PrBaMn2O5+δ-La0.8Sr0.2Ga0.85Mg0.15O3-δ composite electrode by scaffold infiltration for reversible solid oxide fuel cell applications, Int. J. Hydrogen Energy. 45 (2019) 1748–1758.[4] B. Zhang, Y. Wan, Z. Hua, K. Tang, C. Xia, Tungsten-Doped PrBaFe2O5+δ Double Perovskite as a High-Performance Electrode Material for Symmetrical Solid Oxide Fuel Cells, ACS Appl. Energy Mater. 4 (2021) 8401–8409.[5] D. Kim, S.J. Son, M. Kim, H.J. Park, J.H. Joo, PrBaFe2O5+δ promising electrode for redox-stable symmetrical proton-conducting solid oxide fuel cells, J. Eur. Ceram. Soc. 41 (2021) 5939–5946. Figure 1. a) PBFNx-CGO electrode deposited by spray-pyrolysis onto LSGM electrolyte: (i) Low magnification image of the electrode and electrolyte; (ii) Zoomed image of the pure PBFN top layer and the PBFNx layer infiltrated in CGO; and (iii) Zoomed image of PBFNx particles infiltrated on CGO scaffold. b) Polarization resistance (Rp) in air of PBF, PBFNx and PBFNx-CGO electrodes as a function of temperature (450-800 ºC). Figure 1

Effect of A-site cation ordering on oxygen diffusion in NdBa2Fe3O8 through molecular dynamics

RE1+xBa2-xFe3O8+δ (RE = Pr, Nd, Sm, …) compounds have been presented recently as potential electrode materials for Solid Oxide Fuel Cells. Depending on the composition, these materials may present a disordered cubic perovskite phase, an ordered quintuple perovskite or a mixing of both. Such an evolution in the structure would potentially affect the oxygen ion diffusion at the core of the air electrode property. Aiming to identify the influence of such an ordering on oxygen diffusion mechanism, we perform, in the present study, molecular dynamics simulations, through which we determine both macroscopic diffusion coefficients and also extract some information about atomic scale mechanisms for different structures. Similarly to previous results on double cobaltites, we explore if the disordering of A-site cations favours or not oxygen diffusion in these ferrites. We thus studied a fully disordered cubic perovskite structure, a quintuple perovskite structure with ordering on A-site, and a nano-ordered structure which present small domains of the quintuple perovskite phase. We show that this nano-ordering, as observed experimentally, leads to a slight improvement of the oxygen ions diffusion process compared to the fully ordered structure, having still its oxygen diffusion coefficient much smaller than the one of the disordered structure.

Evaluation of La1−xSrxNi0.4Fe0.6O3-δ as Electrode Materials for Direct Methane Symmetrical Solid Oxide Fuel Cells

In this work, La1−xSrxNi0.4Fe0.6O3-δ (0 ≤ x ≤ 0.2) oxides were synthesized and employed as the identical electrode of direct methane symmetrical solid oxide fuel cell (SSOFC). In addition, the phase structure, redox stability, electrical conductivity, chemical compatibility, and thermal expansion of La1−xSrxNi0.4Fe0.6O3-δ oxides were evaluated. The La2NiO4 phase occurs when the amount of doped Sr rises to 0.2. The composition of La0.9Sr0.1Ni0.4Fe0.6O3-δ (LSNF9146) boasts the highest conductivity of 463 S cm−1 with lowest activation energy of 0.066 eV as well as a relatively large thermal expansion coefficient. After treatment in methane for 10 h, the LSNF9146 oxide exhibits 33% lower carbon deposition than the LaNi0.4Fe0.6O3-δ (LNF46) oxide. Moreover, the impregnated LSNF9146 electrode demonstrates lower polarization resistance in both air and methane atmospheres. SSOFCs with impregnated LSNF9146 and LNF46 identical composite electrodes have the maximum power densities of 233 and 170 mW cm−2 at 850 °C in methane, respectively. These results prove that LSNF9146 is a promising symmetrical electrode with high catalytic activity, good redox stability, and coking resistance to direct methane SSOFCs.

Nonstoichiometric Strontium Ferromolybdate as an Electrode Material for Solid Oxide Fuel Cells

This review is devoted to the application of Sr2FeMoO6−δ (SFM) and Sr2F1.5Mo0.5O6−δ (SF1.5M) in La1−xSrxGa1−yMgyO3−δ (LSGM)-based SOFCs. We consider the most relevant physical properties (crystal structure, thermodynamic stability, iron and molybdenum valence states, oxygen vacancy formation and oxygen non-stoichiometry, electrical conductivity), A- and B-site ion substitution, and the performance of SF1+xM SOFCs (polarization resistance, operation with hydrogen, operation with hydrocarbons and methanol). Their properties can be tailored to a particular application by the substitution of different metal cations into their lattices. SF1+xM materials are excellent catalysts in hydrocarbon oxidation and can prevent carbon deposition due to the ability to exchange lattice oxygen with the gaseous phase. Moreover, they are sulfur tolerant. This opens the way to direct hydrocarbon-fueled SOFCs, eliminating the need for external fuel reforming and sulfur removal components. Such SOFCs can be greatly simplified and operate with much higher overall efficiency, thus contributing to the solution to the lack of energy problem in our modern world.

Tailoring the Stability of Ti-Doped Sr2Fe1.4TixMo0.6-xO6-δ Electrode Materials for Solid Oxide Fuel Cells.

In this work, the stability of Sr2(FeMo)O6-δ-type perovskites was tailored by the substitution of Mo with Ti. Redox stable Sr2Fe1.4TixMo0.6-xO6-δ (x = 0.1, 0.2 and 0.3) perovskites were successfully obtained and evaluated as potential electrode materials for SOFCs. The crystal structure as a function of temperature, microstructure, redox stability, and thermal expansion properties in reducing and oxidizing atmospheres, oxygen content change, and transport properties in air and reducing conditions, as well as chemical stability and compatibility towards typical electrolytes have been systematically studied. All Sr2Fe1.4TixMo0.6-xO6-δ compounds exhibit a regular crystal structure with Pm-3m space group, showing excellent stability in oxidizing and reducing conditions. The increase of Ti-doping content in materials increases the thermal expansion coefficient (TEC), oxygen content change, and electrical conductivity in air, while it decreases the conductivity in reducing condition. All three materials are stable and compatible with studied electrolytes. Interestingly, redox stable Sr2Fe1.4Ti0.1Mo0.5O6-δ, possessing 1 μm grain size, low TEC (15.3 × 10-6 K-1), large oxygen content change of 0.72 mol·mol-1 between 30 and 900 °C, satisfactory conductivity of 4.1-7.3 S·cm-1 in 5% H2 at 600-800 °C, and good transport coefficients D and k, could be considered as a potential anode material for SOFCs, and are thus of great interest for further studies.

Magnesium-Doped Sr2(Fe,Mo)O6-δ Double Perovskites with Excellent Redox Stability as Stable Electrode Materials for Symmetrical Solid Oxide Fuel Cells.

In this work, magnesium-doped Sr2Fe1.2Mg0.2Mo0.6O6−δ and Sr2Fe0.9Mg0.4Mo0.7O6−δ double perovskites with excellent redox stability have been successfully obtained. The physicochemical properties including: crystal structure properties, redox stability, thermal expansion properties in oxidizing and reducing conditions, oxygen content as a function of temperature and transport properties, as well as the chemical compatibility with typical electrolytes have been systematically investigated. The in situ oxidation of reduced samples using high-temperature XRD studies shows the crystal structure of materials stable at up to a high-temperature range. The in situ reduction and oxidation of sinters with dilatometer measurements prove the excellent redox stability of materials, with the thermal expansion coefficients measured comparable with electrolytes. The oxygen nonstoichiometry δ of compounds was determined and recorded in air and argon up to 900 °C. Sr2Fe1.2Mg0.2Mo0.6O6−δ oxide presents satisfactory values of electrical conductivity in air (56.2 S·cm−1 at 600 °C) and reducing conditions (10.3 S·cm−1 at 800 °C), relatively high coefficients D and k, and good ionic conductivity (cal. 0.005 S·cm−1 at 800 °C). The stability studies show that both compounds are compatible with Ce0.8Gd0.2O1.9 but react with the La0.8Sr0.2Ga0.8Mg0.2O3−d electrolyte. Therefore, the magnesium-doped double perovskites with excellent redox stability can be potentially qualified as electrode materials for symmetrical SOFCs and are of great interest for further investigations.

Rationalizing Structural Hierarchy in the Design of Fuel Cell Electrode and Electrolyte Materials Derived from Metal-Organic Frameworks

Metal-organic frameworks (MOFs) are arguably a class of highly tuneable polymer-based materials with wide applicability. The arrangement of chemical components and the bonds they form through specific chemical bond associations are critical determining factors in their functionality. In particular, crystalline porous materials continue to inspire their development and advancement towards sustainable and renewable materials for clean energy conversion and storage. An important area of development is the application of MOFs in proton-exchange membrane fuel cells (PEMFCs) and are attractive for efficient low-temperature energy conversion. The practical implementation of fuel cells, however, is faced by performance challenges. To address some of the technical issues, a more critical consideration of key problems is now driving a conceptualised approach to advance the application of PEMFCs. Central to this idea is the emerging field MOF-based systems, which are currently being adopted and proving to be a more efficient and durable means of creating electrodes and electrolytes for proton-exchange membrane fuel cells. This review proposes to discuss some of the key advancements in the modification of PEMs and electrodes, which primarily use functionally important MOFs. Further, we propose to correlate MOF-based PEMFC design and the deeper correlation with performance by comparing proton conductivities and catalytic activities for selected works.

Conductive Geopolymers as Low-Cost Electrode Materials for Microbial Fuel Cells.

Geopolymer (GP) inorganic binders have a superior acid resistance compared to conventional cement (e.g., Portland cement, PC) binders, have better microbial compatibility, and are suitable for introducing electrically conductive additives to improve electron and ion transfer properties. In this study, GP–graphite (GPG) composites and PC–graphite (PCG) composites with a graphite content of 1–10 vol % were prepared and characterized. The electrical conductivity percolation threshold of the GPG and PCG composites was around 7 and 8 vol %, respectively. GPG and PCG composites with a graphite content of 8 to 10 vol % were selected as anode electrodes for the electrochemical analysis in two-chamber polarized microbial fuel cells (MFCs). Graphite electrodes were used as the positive control reference material. Geobacter sulfurreducens was used as a biofilm-forming and electroactive model organism for MFC experiments. Compared to the conventional graphite anodes, the anode-respiring biofilms resulted in equal current production on GPG composite anodes, whereas the PCG composites showed a very poor performance. The largest mean value of the measured current densities of a GPG composite used as anodes in MFCs was 380.4 μA cm–2 with a standard deviation of 129.5 μA cm–2. Overall, the best results were obtained with electrodes having a relatively low Ohmic resistance, that is, GPG composites and graphite. The very first approach employing sustainable GPs as a low-cost electrode binder material in an MFC showed promising results with the potential to greatly reduce the production costs of MFCs, which would also increase the feasibility of MFC large-scale applications.

Tungsten-Doped PrBaFe2O5+δ Double Perovskite as a High-Performance Electrode Material for Symmetrical Solid Oxide Fuel Cells

Tungsten-Doped PrBaFe₂O_5+δ Double Perovskite as a High-Performance Electrode Material for Symmetrical Solid Oxide Fuel Cells

Performance and Stability of Nickelates Based Oxygen Electrodes for Solid Oxide Cells

This work is focused on the development of alternative oxygen electrode materials for Solid Oxide Fuel Cells (SOFCs) and Solid Oxide Electrolysis Cells (SOECs). Rare earth nickelates with general formula Ln2NiO4+δ (Ln = La, Pr or Nd) have shown good performance as oxygen electrodes with various electrolytes. In order to further enhance the physico-chemical properties, electrochemical performance of these nickelates as oxygen electrode, we have performed the substitution of nickel by other transition element such as cobalt. Two compositions of Ln2Ni1-x Co x O4+ δ (Ln = La, Pr, Nd) and La1.5Pr0.5Ni1-x Co x O4+ δ (x=0.1 and 0.2) were mainly considered and completely characterized using several techniques. The single cells were then prepared and electrochemically characterized using DC- and AC-techniques in the temperature range 700-900°C. The stability tests up to 250 h were also investigated at ±1 A.cm-2 current density at 800°C under both SOFC (with 100% H2) and SOEC conditions (with 50% H2 and 50% H2O feed gas mixture) indicating different degradation behavior.

Mechanism and kinetics of catalytic oxidation of CO to CO2 over Ptn+and MPtn-1+, (M=Sn, Rh &Ru; n=3, 4) clusters

Abstract Quantum chemical studies show the elementary effects of doping in the oxidation reaction of CO over Ptn+ and MPtn-1+ (M=Sn, Rh & Ru; n=3, 4) clusters. We have utilized MN12-SX screened-exchange (SX) hybrid functional in conjunction with def2TZVPP basis set to obtain electronic structures and thermochemical properties of all species involved in the reaction. It is found that the co-adsorptions of CO and O2 on pure Pt3+ and Pt4+ clusters are less exothermic, while doped SnPt2+ and SnPt3+ clusters show the most exothermic behavior. Bader charge analysis reveals the most significant dopant-host charge transfer on SnPt2+ and SnPt3+ clusters in the course of CO oxidation. Furthermore, the kinetics of the CO oxidation reaction is evaluated using transition state theory. The results show that the value of the rate constant is the highest for Sn doped Pt clusters in the first oxidation of CO to CO2 molecule than the other clusters. We have found that among the Sn, Rh and Ru doped cationic Pt clusters for CO conversion, Sn acts as a suitable alloy on Pt catalyst for building future catalytic converters and fuel cell electrode materials.

Bifunctional N-Doped Tungsten Trioxide Microspheres as Electrode Materials for Lithium-Ion Batteries and Direct Methanol Fuel Cells

Oxygen vacancies (OVs) have emerged as an efficient strategy to modulate the electronic structures, conductivity, and electrochemical properties of WO3. However, OVs are easily absorbed by water molecules or oxygen atoms, resulting in the poor stability of its electrocatalytic reaction. In the present work, we have demonstrated that nitrogen doping provides an alternative to improve the electrochemical properties of WO3, which plays a series of roles in reducing the band gap, improving the electron mobility, accelerating the Li+ ion diffusion, and providing more active sites for catalytic reactions. Consequently, N-doped WO3 microspheres exhibit low discharge–charge voltage gaps and high capacity retention as well as exceptional rate performance when used as anode materials for lithium-ion batteries (LIBs). Furthermore, the as-prepared Pt/N-WO3 catalyst also exhibits excellent electrocatalytic properties toward methanol electro-oxidation (MOR) including high activity, strong poison tolerance, and outstanding long-term stability owing to the synergetic effects between Pt and N-WO3.

Waste-Biomass-Derived Carbon As Renewable Electrode Materials for Plant Microbial Fuel Cells

Developing clean and sustainable energy sources is important as it deals directly with energy shortage and environmental pollution problems caused by fossil fuels. Plant microbial fuel cells (PMFCs) is a novel technology that can convert solar energy into electrical energy by the microbes at the region of rhizosphere of the plants. Without producing any harmful byproducts during the energy generation process, PMFCs seems to be a promising choice as a renewable power supply technique. Green carbon materials, utilizing agro-industrial waste as precursors, has attracted lots of interest in research recently on account of them being environmental friendly materials and mitigating bio-wastes.To combine the advantages of PMFCs and green carbon materials, the aim of this study is to optimize the electrochemical performance of our designed PMFCs by utilizing biowaste-derived activated carbon materials as the electrode materials. The biowaste-derived activated carbon materials were characterized by Brunauer-Emmett-Teller (BET) surface area analyzer, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The electrochemical performance of PMFCs devices developed by ourselves were analyzed through linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). This study set out to examine the relationship between the properties of activated carbon and the electrochemical performance of PMFCs, expecting to develop a high power density PMFCs device.

Composite Solid Oxide Cell Electrodes Based on Ruddlesden-Popper Nickelates and Co-Doped Ceria

Significant interest has been directed towards the development of high performance air electrodes for solid oxide electrolysis cells, with a wide variety of potential materials considered. Much of the effort has been directed towards modification of conventional solid oxide fuel cell electrode materials, such as La1-xSrxCo1-yFeyO3-d (LSCF) and related perovskites with few studies directed toward new materials. The layered perovskites of the Ruddlesden-Popper (RP) family, Ln2NiO4+d where Ln = rare earth, have begun to receive some attention for this application, but the thermodynamic stability of these phases has precluded their widespread adoption. However the common degradation product of the Ln2NiO4 phases is the relatively high electronic conducting higher order RP materials such as Ln4Ni3O10-d. With the high electronic conductivity and stability in the SOC operating temperature window (600-900oC) these phases where Ln = La, Pr are promising candidates for solid oxide electrolyser application. However the uncertain ionic conductivity of these phases leads to consideration of composite materials exploiting an electrolytic material as the oxide ion conducting phase.In this work we consider the Pr4Ni3O10-d (PNO) -Ce1-x-yPrxGdyO2-d (CGPO) composite phases evaluating the phase compatibility, percolation of the phases and electrode performance characterised using impedance spectroscopy. From evaluation of the impedance responses we find that the optimum performance of the composite electrode was obtained at an operating temperature of 710oC with a 50:50 wt% mixture. The area specific resistance of the electrode was determined to be 0.18 Ωcm2 at 710oC, with a minimum value of 0.08Ωcm2 at 784oC, Figure 1. Further, we evaluate the limiting processes of the cells, finding that at low electrolyte content the composite electrode performance is diffusion limited, whilst at higher electrolyte content the limiting process gradually changes to surface exchange. This work highlights the potential of this composite electrode and the considerable scope for device development based on these new materials. Figure 1

An innovative approach to design SOFC air electrode materials: high entropy La1−xSrx(Co,Cr,Fe,Mn,Ni)O3−δ(x= 0, 0.1, 0.2, 0.3) perovskites synthesized by the sol–gel method

For the first time, the high entropy perovskites from La1−xSrx(Co,Cr,Fe,Mn,Ni)O3−δ(x= 0, 0.1, 0.2, 0.3, 0.4 and 0.5) series are documented to possess attractive properties as a candidate air electrode material for Solid Oxide Fuel Cells (SOFCs).

Electrochemical Synthesis Partially Unzipped Multi-Walled Carbon Nanotubes as Electrode Materials for Fuel Cells

Results of electrochemical anodic oxidation of multi-walled carbon nanotubes in 80% sulfuric acid are presented. Using X-ray diffraction analysis, electron microscopy, and Raman spectra, it has been proven that, as a result of anodic oxidation, partially unzipped multi-walled carbon nanotubes were obtained by anodic oxidation. It is shown that the degree of unzipping multi-walled carbon nanotubes depends on the time of electrochemical oxidation of these materials. Using the oxygen electrode as testing electrodes was shown the dependence of the electrochemical characteristics of these materials of the degree of unzipping the multi-walled carbon nanotubes. It is suggested that the controlled synthesis of partially unzipping nanotubes is possible. It is also suggested that it is possible to estimate the degree of unzipping the nanotube based on the study of the electrochemical characteristics of oxygen electrodes. By the electrochemical method obtained partially unzipped multi-walled carbon nanotubes which are promising electrode materials.

Study of La4BaCu5-xMnxO13+δ materials as potential electrode for symmetrical-SOFC

La4BaCu5-xMnxO13+δ materials have been synthesized by the sol-gel method in air and studied as possible electrode materials for symmetrical Solid Oxide Fuel Cells (S-SOFC). Within the series, La4BaMn5O13+δ (LBMn) exhibits an excellent stability in reducing atmosphere and remarkable redox stability, although a structure transition from rhombohedral to cubic perovskite structure is found beyond 500 °C in air or wet diluted hydrogen. The thermal expansion coefficients (TEC), deduced from HT-XRD study during redox cycling, make the manganite compatible with classical SOFC electrolytes at low temperature; however, relatively high values of 15.8(5) and 18.1(2) K−1 are found in cathode and anode conditions for T > 500 °C. With high electrical conductivities of 178 and 33.3 S cm−1, in air and hydrogen at 800 °C, we demonstrate that the La0.8Ba0.2MnO3±δ manganite fulfils all the preliminary requirements of an electrode material for symmetrical SOFC.

CO2-Derived Manganese-Oxide Carbon Composites As Electrode Materials for Fuel Cells and Supercapacitors

Boron-doped porous carbon impregnated with manganese oxide were synthesized from sodium borohydride (NaBH4) and carbon dioxide (CO2) under a moderate experimental condition (1 bar and 500 ℃) by a facile two-step method. The boron-manganese oxide-carbon nanocomposites exhibited enhanced electrochemical properties in both electrocatalysts for oxygen reduction reaction (ORR) and electrode materials for supercapacitors. The composites showed a four electron transfer pathway and had electrocatalytic activity comparable to that of commercial platinum-carbon catalyst. They also provided a high capacitance (150 F g-1 at 1.0 A g-1 and 136 F g-1 at 10.0 A g-1) compared to that of bare boron-doped carbon (58 F g-1 at 1.0 A g-1 and 15 F g-1 at 10.0 A g-1) due to generation of new active sites, increase in specific surface area, and reduction of overall resistance by efficient interaction within the composites.