Special Issue "Membranes for Electrochemical Energy Applications 2015"

A special issue of Membranes (ISSN 2077-0375). This special issue belongs to the section "Membrane Applications in Water Treatment".

Deadline for manuscript submissions: closed (30 September 2015)

Special Issue Editor

Guest Editor
Prof. Dr. Bruno Scrosati

Department of Chemistry, University Sapienza, Piazzale Aldo Moro 5, 00185 Rome, Italy
E-Mail
Interests: polymer electrolyte membrane fuel cells; lithium polymer batteries

Special Issue Information

Dear Colleagues,

Membranes play a key role in energy-related fields since they are the main components of devices which could help address one of the most serious threats to our society, namely global warming. Serious concern is associated with the continuous CO2 emission resulting from our energy policy, which is still mainly based on burning of fossil fuels. Accordingly, an efficient use of renewable energy sources and the replacement of internal combustion engines with electric motors for the development of sustainable vehicles, such as hybrid vehicles (HEVs), plug-in hybrid vehicles (PHEVs) and ultimately, full electric vehicles (EVs), are major goals in the present energy scenario. On the other hand, an efficient use of alternative, green, energy sources, such as solar and wind, requires the side support of energy storage systems that can compensate for their intermittent characteristics. Analogously, HEVs, PHEVs and EVs require an on-board energy source for powering the electric engine. Among the various choices, electrochemical devices, such as fuel cells and batteries, capable of delivering stored chemical energy as electrical energy with high conversion efficiency and without any gaseous emission, are the most suitable. Moreover, fuel cells and batteries offer a promising option to efficiently power the electric engine in HEVs or EVs.

The most common and most studied fuel cells utilize a perfluorosulfonic membrane electrolyte, mainly of the NAFION® type. Although becoming increasingly well-known over time, these membranes still require attention to further improve performance. Much research is presently being carried out in this area, and this Special Issue will be a perfect forum to bring together the latest results obtained by key laboratories presently engaged in polymer electrolyte membrane fuel cell R&D.

In terms of battery research, particular interest is focused on lithium batteries due to their intrinsic, high energy density value. However, in their present configuration, lithium batteries are affected by a series of issues that still prevent their wide use for electric vehicle application. One of the most serious is the safety concern associated with the unstable and flammable nature of the common liquid electrolytes. Improving safety is thus a present challenge in the field. One approach to reach this goal is to move away from the unreliable liquid, organic electrolytes, to stable and safe polymer electrolyte membranes. There are two classes of these membranes: a polymer-liquid hybrid type, generally named gel-type membranes, and membranes formed by liquid-free combinations of polymer with lithium salts, generally named solid polymer electrolytes. Today there is tremendous research ongoing worldwide is involved into lithium batteries, motivated by a large amount of funding granted in many countries. Therefore, breakthroughs in the area―especially in membrane electrolyte and related polymer batteries―are expected to soon concretize. Again, this Special Issue offers a perfect site for welcoming the latest innovations, and accordingly authors from top laboratories are invited to submit their latest results.

Prof. Dr. Bruno Scrosati
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

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. Membranes is an international peer-reviewed open access monthly 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 1000 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 conducting membranes
  • perfluorosulfonic membranes
  • fuel cells
  • lithium conducting membranes
  • gel-type membranes
  • solvent-free, solid-state membranes
  • lithium batteries

Published Papers (8 papers)

View options order results:
result details:
Displaying articles 1-8
Export citation of selected articles as:

Research

Jump to: Review

Open AccessArticle The Effect of Platinum Electrocatalyst on Membrane Degradation in Polymer Electrolyte Fuel Cells
Membranes 2015, 5(4), 888-902; https://doi.org/10.3390/membranes5040888
Received: 30 September 2015 / Accepted: 1 December 2015 / Published: 8 December 2015
Cited by 7 | PDF Full-text (466 KB) | HTML Full-text | XML Full-text
Abstract
Membrane degradation is a severe factor limiting the lifetime of polymer electrolyte fuel cells. Therefore, obtaining a deeper knowledge is fundamental in order to establish fuel cells as competitive product. A segmented single cell was operated under open circuit voltage with alternating relative [...] Read more.
Membrane degradation is a severe factor limiting the lifetime of polymer electrolyte fuel cells. Therefore, obtaining a deeper knowledge is fundamental in order to establish fuel cells as competitive product. A segmented single cell was operated under open circuit voltage with alternating relative humidity. The influence of the catalyst layer on membrane degradation was evaluated by measuring a membrane without electrodes and a membrane-electrode-assembly under identical conditions. After 100 h of accelerated stress testing the proton conductivity of membrane samples near the anode and cathode was investigated by means of ex situ electrochemical impedance spectroscopy. The membrane sample near the cathode inlet exhibited twofold lower membrane resistance and a resulting twofold higher proton conductivity than the membrane sample near the anode inlet. The results from the fluoride ion analysis have shown that the presence of platinum reduces the fluoride emission rate; which supports conclusions drawn from the literature. Full article
(This article belongs to the Special Issue Membranes for Electrochemical Energy Applications 2015)
Figures

Figure 1

Open AccessArticle Characterization of Polyethylene-Graft-Sulfonated Polyarylsulfone Proton Exchange Membranes for Direct Methanol Fuel Cell Applications
Membranes 2015, 5(4), 875-887; https://doi.org/10.3390/membranes5040875
Received: 22 October 2015 / Revised: 19 November 2015 / Accepted: 19 November 2015 / Published: 4 December 2015
Cited by 1 | PDF Full-text (497 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
This paper examines polymer film morphology and several important properties of polyethylene-graft-sulfonated polyarylene ether sulfone (PE-g-s-PAES) proton exchange membranes (PEMs) for direct methanol fuel cell applications. Due to the extreme surface energy differences between a semi-crystalline and hydrophobic PE backbone and [...] Read more.
This paper examines polymer film morphology and several important properties of polyethylene-graft-sulfonated polyarylene ether sulfone (PE-g-s-PAES) proton exchange membranes (PEMs) for direct methanol fuel cell applications. Due to the extreme surface energy differences between a semi-crystalline and hydrophobic PE backbone and several amorphous and hydrophilic s-PAES side chains, the PE-g-s-PAES membrane self-assembles into a unique morphology, with many proton conductive s-PAES channels embedded in the stable and tough PE matrix and a thin hydrophobic PE layer spontaneously formed on the membrane surfaces. In the bulk, these membranes show good mechanical properties (tensile strength >30 MPa, Young’s modulus >1400 MPa) and low water swelling (λ < 15) even with high IEC >3 mmol/g in the s-PAES domains. On the surface, the thin hydrophobic and semi-crystalline PE layer shows some unusual barrier (protective) properties. In addition to exhibiting higher through-plane conductivity (up to 160 mS/cm) than in-plane conductivity, the PE surface layer minimizes methanol cross-over from anode to cathode with reduced fuel loss, and stops the HO• and HO2• radicals, originally formed at the anode, entering into PEM matrix. Evidently, the thin PE surface layer provides a highly desirable protecting layer for PEMs to reduce fuel loss and increase chemical stability. Overall, the newly developed PE-g-s-PAES membranes offer a desirable set of PEM properties, including conductivity, selectivity, mechanical strength, stability, and cost-effectiveness for direct methanol fuel cell applications. Full article
(This article belongs to the Special Issue Membranes for Electrochemical Energy Applications 2015)
Figures

Figure 1

Open AccessArticle Synthesis and Characterization of Cellulose-Based Hydrogels to Be Used as Gel Electrolytes
Membranes 2015, 5(4), 810-823; https://doi.org/10.3390/membranes5040810
Received: 26 October 2015 / Accepted: 17 November 2015 / Published: 27 November 2015
Cited by 12 | PDF Full-text (603 KB) | HTML Full-text | XML Full-text
Abstract
Cellulose-based hydrogels, obtained by tuned, low-cost synthetic routes, are proposed as convenient gel electrolyte membranes. Hydrogels have been prepared from different types of cellulose by optimized solubilization and crosslinking steps. The obtained gel membranes have been characterized by infrared spectroscopy, scanning electron microscopy, [...] Read more.
Cellulose-based hydrogels, obtained by tuned, low-cost synthetic routes, are proposed as convenient gel electrolyte membranes. Hydrogels have been prepared from different types of cellulose by optimized solubilization and crosslinking steps. The obtained gel membranes have been characterized by infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and mechanical tests in order to investigate the crosslinking occurrence and modifications of cellulose resulting from the synthetic process, morphology of the hydrogels, their thermal stability, and viscoelastic-extensional properties, respectively. Hydrogels liquid uptake capability and ionic conductivity, derived from absorption of aqueous electrolytic solutions, have been evaluated, to assess the successful applicability of the proposed membranes as gel electrolytes for electrochemical devices. To this purpose, the redox behavior of electroactive species entrapped into the hydrogels has been investigated by cyclic voltammetry tests, revealing very high reversibility and ion diffusivity. Full article
(This article belongs to the Special Issue Membranes for Electrochemical Energy Applications 2015)
Figures

Figure 1

Open AccessArticle Selectivity of Direct Methanol Fuel Cell Membranes
Membranes 2015, 5(4), 793-809; https://doi.org/10.3390/membranes5040793
Received: 21 October 2015 / Accepted: 17 November 2015 / Published: 24 November 2015
Cited by 24 | PDF Full-text (668 KB) | HTML Full-text | XML Full-text
Abstract
Sulfonic acid-functionalized polymer electrolyte membranes alternative to Nafion® were developed. These were hydrocarbon systems, such as blend sulfonated polyetheretherketone (s-PEEK), new generation perfluorosulfonic acid (PFSA) systems, and composite zirconium phosphate–PFSA polymers. The membranes varied in terms of composition, equivalent weight, thickness, and [...] Read more.
Sulfonic acid-functionalized polymer electrolyte membranes alternative to Nafion® were developed. These were hydrocarbon systems, such as blend sulfonated polyetheretherketone (s-PEEK), new generation perfluorosulfonic acid (PFSA) systems, and composite zirconium phosphate–PFSA polymers. The membranes varied in terms of composition, equivalent weight, thickness, and filler and were investigated with regard to their methanol permeation characteristics and proton conductivity for application in direct methanol fuel cells. The behavior of the membrane electrode assemblies (MEA) was investigated in fuel cell with the aim to individuate a correlation between membrane characteristics and their performance in a direct methanol fuel cell (DMFC). The power density of the DMFC at 60 °C increased according to a square root-like function of the membrane selectivity. This was defined as the reciprocal of the product between area specific resistance and crossover. The power density achieved at 60 °C for the most promising s-PEEK-based membrane-electrode assembly (MEA) was higher than the benchmark Nafion® 115-based MEA (77 mW·cm−2 vs. 64 mW·cm−2). This result was due to a lower methanol crossover (47 mA·cm−2 equivalent current density for s-PEEK vs. 120 mA·cm−2 for Nafion® 115 at 60 °C as recorded at OCV with 2 M methanol) and a suitable area specific resistance (0.15 Ohm cm2 for s-PEEK vs. 0.22 Ohm cm2 for Nafion® 115). Full article
(This article belongs to the Special Issue Membranes for Electrochemical Energy Applications 2015)
Figures

Figure 1

Open AccessArticle Influence of the Ionic Liquid Type on the Gel Polymer Electrolytes Properties
Membranes 2015, 5(4), 752-771; https://doi.org/10.3390/membranes5040752
Received: 30 September 2015 / Accepted: 17 November 2015 / Published: 19 November 2015
Cited by 11 | PDF Full-text (1579 KB) | HTML Full-text | XML Full-text
Abstract
Gel Polymer Electrolytes (GPEs) composed by ZnTf2 salt, poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP), and different ionic liquids are synthesized using n-methyl-2-pyrrolidone (NMP) as solvent. Three different imidazolium-based ionic liquids containing diverse cations and anions have been explored. Structural and electrical properties of the GPEs [...] Read more.
Gel Polymer Electrolytes (GPEs) composed by ZnTf2 salt, poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP), and different ionic liquids are synthesized using n-methyl-2-pyrrolidone (NMP) as solvent. Three different imidazolium-based ionic liquids containing diverse cations and anions have been explored. Structural and electrical properties of the GPEs varying the ZnTf2 concentration are analyzed by ATR-FTIR, DSC, TG, and cyclic voltammetry. Free salt IL-GPEs present distinct behavior because they are influenced by the different IL cations and anions composition. However, inclusion of ZnTf2 salt inside the polymers provide GPEs with very similar characteristics, pointing out that ionic transport properties are principally caused by Zn2+ and triflate movement. Whatever the IL used, the presence of NMP solvent inside the polymer’s matrix turns out to be a key factor for improving the Zn2+ transport inside the GPE due to the interaction between Zn2+ cations and carbonyl groups of the NMP. High values of ionic conductivity, low activation energy values, and good voltammetric reversibility obtained regardless of the ionic liquid used enable these GPEs to be applied in Zn batteries. Capacities of 110–120 mAh·g−1 have been obtained for Zn/IL-GPE/MnO2 batteries discharged at −1 mA·cm−2. Full article
(This article belongs to the Special Issue Membranes for Electrochemical Energy Applications 2015)
Figures

Figure 1

Open AccessArticle Corrosion Protection of Al/Au/ZnO Anode for Hybrid Cell Application
Membranes 2015, 5(4), 739-751; https://doi.org/10.3390/membranes5040739
Received: 18 September 2015 / Accepted: 11 November 2015 / Published: 16 November 2015
Cited by 1 | PDF Full-text (687 KB) | HTML Full-text | XML Full-text
Abstract
Effective protection of power sources from corrosion is critical in the development of abiotic fuel cells, biofuel cells, hybrid cells and biobateries for implantable bioelectronics. Corrosion of these bioelectronic devices result in device inability to generate bioelectricity. In this paper Al/Au/ZnO was considered [...] Read more.
Effective protection of power sources from corrosion is critical in the development of abiotic fuel cells, biofuel cells, hybrid cells and biobateries for implantable bioelectronics. Corrosion of these bioelectronic devices result in device inability to generate bioelectricity. In this paper Al/Au/ZnO was considered as a possible anodic substrate for the development of a hybrid cell. The protective abilities of corrosive resistant aluminum hydroxide and zinc phosphite composite films formed on the surface of Al/Au/ZnO anode in various electrolyte environments were examined by electrochemical methods. The presence of phosphate buffer and physiological saline (NaCl) buffer allows for the formation of aluminum hyrdroxide and zinc phosphite composite films on the surface of the Al/Au/ZnO anode that prevent further corrosion of the anode. The highly protective films formed on the Al/Au/ZnO anode during energy harvesting in a physiological saline environment resulted in 98.5% corrosion protective efficiency, thereby demonstrating that the formation of aluminum hydroxide and zinc phosphite composite films are effective in the prevention of anode corrosion during energy harvesting. A cell assembly consisting of the Al/Au/ZnO anode and platinum cathode resulted in an open circuit voltage of 1.03 V. A maximum power density of 955.3 mW/ cm2 in physiological saline buffer at a cell voltage and current density of 345 mV and 2.89 mA/ cm2, respectively. Full article
(This article belongs to the Special Issue Membranes for Electrochemical Energy Applications 2015)
Figures

Figure 1

Open AccessArticle High Temperature Stable Separator for Lithium Batteries Based on SiO2 and Hydroxypropyl Guar Gum
Membranes 2015, 5(4), 632-645; https://doi.org/10.3390/membranes5040632
Received: 16 September 2015 / Accepted: 15 October 2015 / Published: 23 October 2015
Cited by 11 | PDF Full-text (484 KB) | HTML Full-text | XML Full-text
Abstract
A novel membrane based on silicon dioxide (SiO2) and hydroxypropyl guar gum (HPG) as binder is presented and tested as a separator for lithium-ion batteries. The separator is made with renewable and low cost materials and an environmentally friendly manufacturing processing [...] Read more.
A novel membrane based on silicon dioxide (SiO2) and hydroxypropyl guar gum (HPG) as binder is presented and tested as a separator for lithium-ion batteries. The separator is made with renewable and low cost materials and an environmentally friendly manufacturing processing using only water as solvent. The separator offers superior wettability and high electrolyte uptake due to the optimized porosity and the good affinity of SiO2 and guar gum microstructure towards organic liquid electrolytes. Additionally, the separator shows high thermal stability and no dimensional-shrinkage at high temperatures due to the use of the ceramic filler and the thermally stable natural polymer. The electrochemical tests show the good electrochemical stability of the separator in a wide range of potential, as well as its outstanding cycle performance. Full article
(This article belongs to the Special Issue Membranes for Electrochemical Energy Applications 2015)
Figures

Figure 1

Review

Jump to: Research

Open AccessReview NMR Studies of Solvent-Free Ceramic Composite Polymer Electrolytes—A Brief Review
Membranes 2015, 5(4), 915-923; https://doi.org/10.3390/membranes5040915
Received: 19 November 2015 / Revised: 8 December 2015 / Accepted: 8 December 2015 / Published: 14 December 2015
Cited by 1 | PDF Full-text (751 KB) | HTML Full-text | XML Full-text
Abstract
Polyether-based polymer electrolytes containing ceramic inorganic oxide fillers often exhibit improved mechanical and ion transport properties compared to their filler-free counterparts. The nature of local scale interactions that give rise to these enhanced properties is explored by nuclear magnetic resonance measurements. Full article
(This article belongs to the Special Issue Membranes for Electrochemical Energy Applications 2015)
Figures

Figure 1

Membranes EISSN 2077-0375 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top