Papers by Keyword: Fuel Cell

Abstract: Bipolar plates are key components in fuel cells, and their performance strongly depends on the geometry of the microchannels used to distribute reactant gases. Producing channels with sufficient depth in thin metal sheets remains challenging, particularly when cost-effective manufacturing routes are required. This work investigates a multi-stage roller embossing process for forming bipolar plate channels using additively manufactured polymer tools. By dividing the total deformation into multiple forming stages, the process reduces tool deflection that typically limits channel depth in single-pass embossing. Experiments conducted on 0.1 mm stainless steel foil show that the multi-stage approach increases the achievable average channel depth from approximately 0.25 mm in a single pass to approximately 0.34 mm, resulting in a maximum aspect ratio (channel depth to width) of 0.314. These results indicate that combining multi-stage forming with 3D-printed tooling provides a practical route for flexible and low-cost fabrication of metallic bipolar plates, especially for low volume production.

Abstract: Recent interests in hybrid polymers for fuel cell applications have given rise to the exploration, modification, and application of various polymer ionomers. Polymer membranes doped with suitable fillers have improved fuel cell performance compared to the pristine polymers. In this study, three ionomers, PAN, PVP, and PVA were synthesised idividually and then functionalised with zirconium phosphate nanoparticles as membrane nanofillers. The nanofibers were synthesised using the sol-gel polymerisation method from their respective precursors dissolved in either water or DMF solution. This was followed by their subsequent fabrication through the incorporation of the zirconium phosphate nanoparticles, which were synthesised from their precursor salt using the precipitation method. Techniques such as SEM, FTIR, TGA, and XRD were employed to characterise the physiochemical properties of the synthesised polymers. In addition, the electrochemical properties of the synthesised polymers were evaluated using CV and EIS. The obtained results showed that conductive nanofibers were successfully synthesized. As the scan rates increased under cyclic voltammetry, the reduction peak for PVP voltammograms disappeared, and the PAN exhibited an irreversible redox system. It is also noticeable that when scan speeds increase, the oxidation peaks for PAN voltammograms shift to higher potentials. On the other hand, the TGA results indicated that these nanoparticles had excellent thermal stabilities, making them suitable for use in fuel cell membranes under tough conditions. Based on these findings, PAN, PVA, and PVP polymer materials can be used as filler (dopant) materials for fuel cell membranes.

Abstract: The Sustainable Development Goal, SDG No. 3 of the UN, is to develop healthcare for all. Nigeria's healthcare policy is to make primary healthcare the bedrock of the national healthcare system. A dearth of access to electricity is the most critical impediment to quality healthcare delivery in Nigeria. Fragile and inadequate capacity has bedevilled the national grid, making connection to the grid either impossible or ineffective. Out of the over 34,000 Primary Healthcare Centres in the country, 40% lack access to any form of electricity. Renewables are being used to meet the electricity demand in rural and isolated communities. The present study investigates wind and solar renewable energy resources in Abuja with a view to generating electricity that will be sufficient to power a typical rural healthcare centre, while the excess renewable energy is used for hydrogen production that will later be used to power the healthcare centre when the renewable resources are unavailable or inadequate. A wind energy conversion system, solar PV, and electrolyser-hydrogen tank-fuel cell configuration were designed to meet the electrical load at the primary healthcare centre. In situ and satellite-based meteorological data were assessed. Weibull and Logistic distributions were used to assess resource availability. Homer Pro was used for the design of the off-grid system. The Levelized Cost of Energy and Net Present Cost of Energy were found to be $2.53 and $134,123, respectively. The system was able to meet all the load requirements for the 25 years, with an annual excess electricity is 3,179kWh and 2.02kWh of unmet load and a capacity shortage of 4.08kWh.

Abstract: Hydrogen, a zero-carbon energy source with high energy density, is widely used in Proton Exchange Membrane Fuel Cells (PEMFC), where Membrane Electrode Assembly (MEA) plays an important role. This study examines the fabrication of MEAs using the Catalyst Coated Membrane (CCM) technique by airbrush spray and ultrasonic spray methods, using Pt/C catalysts on activated carbon from kepok banana peel (soft carbon) and carbon nanotubes (CNT). Activated carbon soaked with 1M NaOH for 3 hours showed a surface area of 163.075 m²/g, exceeding that of CNTs (101.466 m²/g). The Pt/C catalyst with 1M3H-1 configuration achieved the highest Pt content (52.99 wt%). The ultrasonic spray ensured an even distribution of the catalyst, with a power density of 0.167 mW/cm² (1M3H-1) achieved faster. Although the airbrush spray reaches 0.889 mW/cm² (CNT1), the time required is longer, making the ultrasonic spray more efficient.

Abstract: In this study, synthesis of reduced graphene oxide-iron oxide-silica dioxide (rGO/Fe₃O₄/SiO₂) was done through a facile chemical process. Physical characterization was carried out as such Fourier transform infrared spectroscopy (FTIR) which confirmed the presence of silica peak in the spectrum of rGO/Fe₃O₄/SiO₂, while RAMAN displayed the vibrational bands of carbon materials studied. Results of SEM-EDX and TEM confirmed the unification of SiO₂ on rGO/Fe₃O₄ nanocomposite with difference in morphologic structure. X-ray diffraction (XRD) analysis exhibited that addition of SiO₂ increased the crystalline size of the nanocomposite. Nitrogen adsorption isotherm analysis describes the nanocomposites fall in the mesopore region. The nanocomposite was then drop-casted on the surface of glassy carbon electrode (GCE) for fabrication of the electrode which denoted as rGO/Fe₃O₄/SiO₂/GCE. Electrochemical characterization of modified electrode was studied using electron impedance spectroscopy (EIS), which showed the minimal resistance charge transfer. Oxygen reduction reaction analysis shows that electrocatalytic reduction of oxygen was excellent with four-electron transfer when calculated using Randles-Sevcik equation. All the analysis was compared to the nanocomposites without the addition of silica oxide (rGO/Fe₃O₄)_. This work proves that addition of nanoparticle in a compound as a matrix improves the oxygen reduction potential of rGO/Fe₃O₄/SiO₂/GCE composite.

Abstract: Mesoporous silica nanoparticles were synthesized via sol–gel method to produce uniform size nanoparticles using n-Octadecyl-trimethoxy silane which gives a good dispersion of silica nanoparticles in hydrophobic mediums. Scanning electron microscopy (SEM), infrared spectroscopy, X-ray diffraction (XRD), thermal gravimetric analysis, and nitrogen adsorption-desorption tests were used to thoroughly investigate the nanocomposites' morphology and structure. BET results show a high surface are of 760 m²/g and specific high pore size (30Ȧ) and pore volume (0.336 cm³/g). The SEM results present that the mesoporous silica nanoparticles possess a well dispersed and uniform particle morphology and FTIR interpenetrating the well-prepared silica nanoparticles which possess Si-O-Si and Si-O bond. The XRD analysis confirmed the amorphous nature silica nanoparticles. The electrochemical properties of silica nanoparticles were evaluated in a potassium chloride solution. With the advantages of a large specific surface area and a suitable pore size distribution, a pair of broad and symmetric redox peaks centred at -0.15 V and 0.6 V appears. Mesoporous silica with a large effective specific surface area demonstrated excellent electrochemical performance, making them excellent candidates for supercapacitors and fuel cells.

Abstract: The most promising direction in alternative energy is hydrogen energy, using hydrogen as a secondary energy carrier. A key component in hydrogen energy is a fuel cell, especially on solid polymer membranes. Increasing the efficiency, reducing the cost and increasing the service life of such elements is the primary task of this direction. These tasks need to be solved from two sides: by improving the parameters of platinum catalysts in electrochemical reactions of energy sources, as well as by improving the qualities of the membrane. The aim of the work is to synthesize and study composites with palladium and platinum nanoparticles in hydrogen-oxygen fuel cells.

Abstract: Increasing durability of catalysts used in fuel cells is a necessary condition for their widespread commercialization. Fulfilling this condition requires understanding the catalyst degradation mechanism to propose how to reduce it. Transmission electron microscopy can help solve this problem thanks to the fact that it enables direct observation and thus unambiguous interpretation of the processes taking place. For this purpose, Identical Location Transmission Electron Microscopy (IL-TEM) was applied for observations of a commercial catalyst (platinum nanoparticles with a diameter of about 2 nm deposited on Vulcan carbon black) before and after durability tests. Obtained results may contribute to the development of better models of phenomena occurring during cell operation.

Abstract: Renewable energy source is a clean energy production source and can overcome climatic challenges caused by the excessive use of fossil fuels. The nanocrystalline material of composition Cu_0.2Fe_0.2(Ce_0.6Gd_0.4-xNd_x)_0.6O_2-x has been synthesized by WOWS sol-gel process by varying Neodymium as such x= 0.0, 0.05. These samples were calcined at 500°C for 2 hours and the pellets were sintered at 750°C for 5 hours. X-Ray Diffraction technique confirms the cubic fluorite structure of the material. The doped material has showed high dielectric constant value and low dissipation factor and increased AC conductivity. AC conductivity obeys the Universal Dielectric Response. The material shows the potential for applications such as an electrode/electrolyte for fuel cells or also as a dielectric resonator.

Abstract: Efficient bipolar plates are needed to store electricity from renewable energies. Here the focus is concentrating on graphite-compound-Bipolar plates, which are one of the most used components in a Fuel Cell Stack system. Among other things, polypropylene is a suitable matrix material, but other polymer materials such as PPS and PVDF and phenolic resins can also be considered. However, for a correspondingly high conductivity in the fuel cell system, the plastic must be filled with up to more than 80 % graphite. To ensure that the compound is not brittle afterwards and is as easy to process as possible, an impact modify cation was further developed that makes it possible to produce thin films.