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Special Issue "Hydrogen Storage and Fuel Cells: Materials, Characterization and Applications"

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Energy Materials".

Deadline for manuscript submissions: closed (30 April 2021).

Special Issue Editor

Dr. Rolando Pedicini
E-Mail Website
Guest Editor
Istituto Di Tecnologie Avanzate Per L'energia, Messina, Italy
Interests: polymer functionalization; composite materials; metal alloy and carbon porous materials development; morphological and structural characterization (SEM-EDX, BET, and XRD); volumetric and gravimetric measurements
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

Hydrogen is a green energy vector that is considered to be one of the most promising fuels for the future. One of the devices that uses hydrogen as fuel is the fuel cell. Through this electrochemical system, it is possible to produce clean electricity in which the waste product is steam water. There are different types of fuel cells, but in this Special Issue we will only consider devices that operate at low temperatures and that use hydrogen as fuel. Among these, we will consider the H2-polymer electrolyte membrane fuel cell, and alkaline fuel cells, devices.

The hydrogen storage issue is critical to the growth of hydrogen fuel cells for both stationary and mobile applications. Three types of techniques can be used for hydrogen storage: compressed, liquid, and stored in a solid material. In ‘’Hydrogen Storage and Fuel Cells: Materials, Characterization, and Applications’’, we will focus our attention on the latter method, considering all kind of materials such as metal hydrides, chemical hydrides, carbon materials, the metallic organic framework, and composite materials. Moreover, there will be particular attention paid to engineering and problems related to the integration of H2 storage systems and fuel cell devices. Attention will also be paid to the commercial aspect and the development of the individual and/or integrated H2 storage system/fuel cell.

This Special Issue of Materials will cover but will not be limited to the following topics:

  • Hydrogen storage;
  • Hydrogen storage review;
  • Metal hydrides;
  • Chemical hydrides;
  • High surface area adsorbents;
  • Fuel cells;
  • Polymer electrolyte membrane fuel cells (PEMFC);
  • Alkaline membrane fuel cells (AMFC);
  • Hydrogen storage systems and fuel cells interaction: engineering aspects;
  • Near-term markets.

Dr. Rolando Pedicini
Guest Editor

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Hydrogen storage
  • Hydrogen storage review
  • Metal hydrides
  • Chemical hydrides
  • High surface area adsorbents
  • Fuel cells
  • Polymer electrolyte membrane fuel cells (PEMFC)
  • Alkaline membrane fuel cells (AMFC)
  • Hydrogen storage systems and fuel cells interaction: engineering aspects
  • Near-term markets.

Published Papers (8 papers)

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Research

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Article
A Process for Hydrogen Production from the Catalytic Decomposition of Formic Acid over Iridium—Palladium Nanoparticles
Materials 2021, 14(12), 3258; https://doi.org/10.3390/ma14123258 - 12 Jun 2021
Viewed by 583
Abstract
The present study investigates a process for the selective production of hydrogen from the catalytic decomposition of formic acid in the presence of iridium and iridium–palladium nanoparticles under various conditions. It was found that a loading of 1 wt.% of 2% palladium in [...] Read more.
The present study investigates a process for the selective production of hydrogen from the catalytic decomposition of formic acid in the presence of iridium and iridium–palladium nanoparticles under various conditions. It was found that a loading of 1 wt.% of 2% palladium in the presence of 1% iridium over activated charcoal led to a 43% conversion of formic acid to hydrogen at room temperature after 4 h. Increasing the temperature to 60 °C led to further decomposition and an improvement in conversion yield to 63%. Dilution of formic acid from 0.5 to 0.2 M improved the decomposition, reaching conversion to 81%. The reported process could potentially be used in commercial applications. Full article
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Article
Insight towards Nucleation Mechanism and Change in Morphology for Nanostructured Platinum Thin Film Directly Grown on Carbon Substrate via Electrochemical Deposition
Materials 2021, 14(9), 2330; https://doi.org/10.3390/ma14092330 - 30 Apr 2021
Cited by 1 | Viewed by 422
Abstract
Nanocrystalline platinum with different morphologies is synthesized via electrochemical deposition technique. The nucleation mechanism and its structural effect over the electrodeposited Pt on carbon electrodes have been systematically studied. Powder X-ray diffraction, X-ray photoelectron spectroscopy, and field-emission scanning electron microscopy are employed to [...] Read more.
Nanocrystalline platinum with different morphologies is synthesized via electrochemical deposition technique. The nucleation mechanism and its structural effect over the electrodeposited Pt on carbon electrodes have been systematically studied. Powder X-ray diffraction, X-ray photoelectron spectroscopy, and field-emission scanning electron microscopy are employed to study nucleation, oxidation states, and Pt structure growth on a carbon electrode. This study reports significant development of Pt metal nanoparticles with different morphologies such as a sphere, flower, core-flower, and rod-like structure directly fabricated on carbon electrode while tuning the deposition parameters such as current density, time, temperature, pH during the deposition process. The proposed electrochemical route represents a superior fabrication procedure for large-scale electrode fabrication compared to a conventional method for preparing membrane electrode assemblies for fuel cell stacks. Full article
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Article
Hydrophilic Cross-Linked Aliphatic Hydrocarbon Diblock Copolymer as Proton Exchange Membrane for Fuel Cells
Materials 2021, 14(7), 1617; https://doi.org/10.3390/ma14071617 - 26 Mar 2021
Viewed by 392
Abstract
This study proposes a hydrophobic and hydrophilic aliphatic diblock copolymer wherein the hydrophobic block contains glycidyl methacrylate (GMA) units that are distanced by poly(acrylonitrile) (PAN) segments to fabricate a proton exchange membrane (PEM). This diblock copolymer also known as ionomer due to the [...] Read more.
This study proposes a hydrophobic and hydrophilic aliphatic diblock copolymer wherein the hydrophobic block contains glycidyl methacrylate (GMA) units that are distanced by poly(acrylonitrile) (PAN) segments to fabricate a proton exchange membrane (PEM). This diblock copolymer also known as ionomer due to the hydrophilic block comprising 3-sulfopropyl methacrylate potassium salt (SPM) block. The diblock copolymer was synthesized in the one-pot atom transfer radical polymerization (ATRP) synthesis. Subsequently, the membrane was fabricated by means of solution casting in which an organic diamine, e.g., ethylene diamine (EDA), was introduced to crosslink the diblock copolymer chains via the addition of amine to the epoxide group of GMA. As a result, the PEM attained possesses dual continuous phases, in which the hydrophobic domains are either agglomerated or bridged by the EDA-derived crosslinks, whereas the hydrophilic domains constitute the primary proton conducting channels. The in-situ crosslinking hydrophobic block by using a hydrophilic cross-linker represents the merit aspect since it leads to both improved proton conductivity and dimensional stability in alcohol fuel. To characterize the above properties, Nafion® 117 and random copolymer of P(AN-co-GMA-co-SPM) were used as control samples. The PEM with the optimized composition demonstrates slightly better fuel cell performance than Nafion 117. Lastly, this diblock ionomer is nonfluorinated and hence favors lowering down both material and environmental costs. Full article
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Article
Effects of the Chemical Treatment on the Physical-Chemical and Electrochemical Properties of the Commercial Nafion™ NR212 Membrane
Materials 2020, 13(22), 5254; https://doi.org/10.3390/ma13225254 - 20 Nov 2020
Viewed by 450
Abstract
Polymer Electrolyte Fuel Cells (PEFCs) are one of the most promising power generation systems. The main component of a PEFC is the proton exchange membrane (PEM), object of intense research to improve the efficiency of the cell. The most commonly and commercially successful [...] Read more.
Polymer Electrolyte Fuel Cells (PEFCs) are one of the most promising power generation systems. The main component of a PEFC is the proton exchange membrane (PEM), object of intense research to improve the efficiency of the cell. The most commonly and commercially successful used PEMs are Nafion™ perfluorosulfonic acid (PFSA) membranes, taken as a reference for the development of innovative and alternative membranes. Usually, these membranes undergo different pre-treatments to enhance their characteristics. With the aim of understanding the utility and the effects of such pre-treatments, in this study, a commercial Nafion™ NR212 membrane was subjected to two different chemical pre-treatments, before usage. HNO3 or H2O2 were selected as chemical agents because the most widely used ones in the procedure protocols in order to prepare the membrane in a well-defined reference state. The pre-treated membranes properties were compared to an untreated membrane, used as-received. The investigation has showed that the pre-treatments enhance the hydrophilicity and increase the water molecules coordinated to the sulphonic groups in the membrane structure, on the other hand the swelling of the membranes also increases. As a consequence, the untreated membrane shows a better mechanical resistance, a good electrochemical performance and durability in fuel cell operations, orienting toward the use of the NR212 membrane without any chemical pre-treatment. Full article
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Article
Ionic Transport Properties of P2O5-SiO2 Glassy Protonic Composites Doped with Polymer and Inorganic Titanium-based Fillers
Materials 2020, 13(13), 3004; https://doi.org/10.3390/ma13133004 - 06 Jul 2020
Cited by 1 | Viewed by 651
Abstract
This paper is focused on the determination of the physicochemical properties of a composite inorganic–organic modified membrane. The electrical conductivity of a family of glassy protonic electrolytes defined by the general formula (P2O5)x(SiO2)y, [...] Read more.
This paper is focused on the determination of the physicochemical properties of a composite inorganic–organic modified membrane. The electrical conductivity of a family of glassy protonic electrolytes defined by the general formula (P2O5)x(SiO2)y, where x/y is 3/7 are studied by Alternating Current electrochemical impedance spectroscopy (AC EIS) method. The reference glass was doped with polymeric additives—poly(ethylene oxide) (PEO) and poly(vinyl alcohol) (PVA), and additionally with a titanium-oxide-based filler. Special attention was paid to determination of the transport properties of the materials thus modified in relation to the charge transfer phenomena occurring within them. The electrical conductivities of the ‘dry’ material ranged from 10−4 to 10−9 S/cm, whereas for ‘wet’ samples the values were ~10−3 S/cm. The additives also modified the pore space of the samples. The pore distribution and specific surface of the modified glassy systems exhibited variation with changes in electrolyte chemical composition. The mechanical properties of the samples were also examined. The Young’s modulus and Poisson’s ratio were determined by the continuous wave technique (CWT). Based on analysis of the dispersion of the dielectric losses, it was found that the composite samples exhibit mixed-type proton mobility with contributions related to both the bulk of the material and the surface of the pore space. Full article
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Article
Molybdenum Oxide and Nickel Nitrate as Cooperative Sintering Aids for Yttria-Stabilized Zirconia
Materials 2020, 13(12), 2875; https://doi.org/10.3390/ma13122875 - 26 Jun 2020
Viewed by 700
Abstract
The entirely accidental observation of increased sintering performance of nickel-infiltrated yttria-stabilized zirconia (8YSZ) in a molybdenum and oxygen rich atmosphere was explored. Molybdenum and nickel were found to be synergistic sintering aids for 8YSZ. However, sintering had to take place in an atmosphere [...] Read more.
The entirely accidental observation of increased sintering performance of nickel-infiltrated yttria-stabilized zirconia (8YSZ) in a molybdenum and oxygen rich atmosphere was explored. Molybdenum and nickel were found to be synergistic sintering aids for 8YSZ. However, sintering had to take place in an atmosphere of flowing oxygen. Samples sintered in air consistently burst. The sintering performance, microstructure, and crystal structure of 8YSZ with additions of both Mo and Ni together are compared to the sintering performance, microstructure, and crystal structure of pure 8YSZ, 8YSZ with only Ni added as a sintering aid, and 8YSZ with only Mo added as a sintering aid. Enhanced densification and grain growth is observed in the Mo–Ni 8YSZ samples when compared to all other sintering samples. Order of magnitude sintering rate increases are observed in the Mo–Ni 8YSZ over that of pure 8YSZ. With a maximum sintering temperature of 1200 °C and a one-hour dwell, sintered densities of 85% theoretical density (5.02 g⁄cm3) are achieved with the Mo–Ni samples: a 57% increase in density over pure 8YSZ sintered with the same sintering profile. EIS results suggest conductivity may not be negatively impacted by the use of these two sintering aids at temperatures above 750 °C. Finally, the spontaneous generation of nickel-molybdenum nano-rods was observed on the 5, and 10 mol.% Mo–Ni infiltrated 8YSZ samples after being left under vacuum in a scanning electron microscope chamber, suggesting evaporation of a possible nickel–molybdenum compound from the sample fracture surfaces. Full article
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Article
Composite Sulfonated Polyether-Ether Ketone Membranes with SBA-15 for Electrochemical Energy Systems
Materials 2020, 13(7), 1570; https://doi.org/10.3390/ma13071570 - 29 Mar 2020
Cited by 2 | Viewed by 804
Abstract
The aim of this work is the evaluation of a Sulfonated Poly Ether-Ether Ketone (S-PEEK) polymer modified by the addition of pure Santa Barbara Amorphous-15 (SBA-15, mesoporous silica) and SBA-15 previously impregnated with phosphotungstic acid (PWA) fillers (PWA/SBA-15) in order to prepare composite [...] Read more.
The aim of this work is the evaluation of a Sulfonated Poly Ether-Ether Ketone (S-PEEK) polymer modified by the addition of pure Santa Barbara Amorphous-15 (SBA-15, mesoporous silica) and SBA-15 previously impregnated with phosphotungstic acid (PWA) fillers (PWA/SBA-15) in order to prepare composite membranes as an alternative to conventional Nafion® membranes. This component is intended to be used as an electrolyte in electrochemical energy systems such as hydrogen and methanol Proton Exchange Membrane Fuel Cell (PEMFC) and Electrochemical Hydrogen Pumping (EHP). The common requirements for all the applications are high proton conductivity, thermomechanical stability, and fuel and oxidant impermeability. The morphology of the composite membranes was investigated by Scanning Electron Microscopy- Energy Dispersive X-ray Spectroscopy (SEM-EDS) analysis. Water Uptake (Wup), Ion Exchange Capacity (IEC), proton conductivity, methanol permeability and other physicochemical properties were evaluated. In PEMFC tests, the S-PEEK membrane with a 10 wt.% SBA-15 loading showed the highest performance. For EHP, the inclusion of inorganic materials led to a back-diffusion, limiting the compression capacity. Concerning methanol permeability, the lowest methanol crossover corresponded to the composites containing 5 wt.% and 10 wt.% SBA-15. Full article
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Review

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Review
Research Progress of Proton Exchange Membrane Failure and Mitigation Strategies
Materials 2021, 14(10), 2591; https://doi.org/10.3390/ma14102591 - 16 May 2021
Cited by 1 | Viewed by 600
Abstract
Proton exchange membrane (PEM) is critical for the efficient, reliable and safe operation of proton exchange membrane fuel cells (PEMFC). The lifetime of PEM is the main factor restricting the commercialization of PEMFC. The complexity of operating conditions, such as open-circuit/idling, dynamic load [...] Read more.
Proton exchange membrane (PEM) is critical for the efficient, reliable and safe operation of proton exchange membrane fuel cells (PEMFC). The lifetime of PEM is the main factor restricting the commercialization of PEMFC. The complexity of operating conditions, such as open-circuit/idling, dynamic load and startup-shutdown under automotive conditions, on PEMFC will cause the mechanical and chemical degradation of PEM and affect the service life of PEMFC. In order to understand the degradation behavior and durability of PEM, this paper presents an overview of the degradation failure mechanism and mitigation strategies of PEM. The mechanical and chemical degradation behavior of PEM and its causes, as well as the mitigation strategies are discussed in order to give a direction for PEM design and fuel cell system control strategy. It is proposed as a primary principle in order to further develop and promote the durability of PEM, to focus on the material improvement and system engineering. Full article
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