Special Issue "Advancements in Membranes for Electrochemical Energy Applications"

Guest Editor
Prof. Dr. Bruno Scrosati
Department of Chemistry, University Sapienza, Piazzale Aldo Moro 5, 00185 Rome, Italy
E-Mail: bruno.scrosati@uniroma1.it
Phone: +39 06 4991 3530
Interests: polymer electrolyte membrane fuel cells; lithium polymer batteries

Dear Colleagues,

This Special Issue came as the natural consequence of the great success of the previous one “Membranes for Electrochemical Energy Applications”.

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 second 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 second 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

Submission

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. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as 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 refereed through a 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 quarterly 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 300 CHF (Swiss Francs). English correction and/or formatting fees of 250 CHF (Swiss Francs) will be charged in certain cases for those articles accepted for publication that require extensive additional formatting and/or English corrections.

• hydrogen conducting membranes
• perfluorosulfonic membranes
• fuel cells
• lithium conducting membranes
• gel-type membranes
• solvent-free, solid-state membranes
• lithium batteries

Type of Paper: Article
Title: Testing the Chemical/Structural Stability of Proton Conducting Perovskite Ceramic Membranes by in situ Autoclave Raman Microscopy
Author: Aneta Slodczyk, Settakorn Upasen and Philippe Colomban *
Affiliation: LADIR, UMR7075 CNRS, Université Pierre et Marie Curie (UPMC), 4 Place Jussieu, Paris 75005, France
Abstract: Ceramics exhibiting high proton conductivity at moderate temperature are researched as electrolyte membranes or electrode components of fuel cells, electrolysers or CO2 converters. In severe operating conditions: under high partial pressure and high temperature, a significant increase of the chemical activity of potentially reacting atmospheres (water, CO2, etc.) is systematically observed. This can lead to mechanical, chemical and structural instability of membranes and premature efficiency loss. Since a device lifetime duration determines the economical interest, the stability/ageing tests are then essential. Consequently, we developed the autoclave allowing in situ study of perovskite ceramics in the 25–620 °C temperature range, under 1–50 bar of water vapour or CO2 pressure, with or without application of an electric field, equipped with a sapphire window and coupled with Raman microspectrometer (532 or 785 nm excitation). Taking examples of different compositions (LiNbO3, BaZr1-xLnxO3, SrZr1-xLnxO3, …) we will demonstrate the high potential of our unique set-up to discriminate between good/stable and instable electrolytes (accelerating stability test) as well as to detect and monitor in situ: (i) the sample surface reaction with surrounding atmosphere and the formation of crystalline or amorphous second phases (carbonates, hydroxides, hydrates, etc.) hardly or not detectable by X-ray diffraction, and (ii) structural modifications of the host structure as a function of operating conditions. The results of these studies allow to determine the conditions preserving the membrane stability and to go further in comprehension of ageing mechanism.

Type of Paper: Article
Title: Interface Properties between Lithium Metal and a Composite Polymer Electrolyte of PEO18Li(CF3SO2)2N-tetra(ethylene) Glycol Dimethyl Ether
Author: H.Wang ¹, M.Matsui ¹, T.Takeda ¹, O.Yamamoto ¹,*, D.Im ², D.J.Lee ² and N.Imanishi ¹
Affiliation: ¹ Graduate School of Engineering, Mie University, Tsu, Mie, 514-8507, Japan
² Samsung Advanced Institute of Technology, Samsung Electronic, Yongin, 446-712, Korea
Abstract: The electrochemical properties of a composite solid polymer electrolyte consisting of polyethylene oxide (PEO)-lithium trifluoromethanesulfonylimide (LiTFSI) and tetra (ethylene) glycol dimethyl ether (TEGDME) was studied as a protect layer between lithium metal and a water-stable lithium ion-conducting glass ceramic of Li1.35Ti1.75Al0.25P0.9Si0.1O12. The lithium ion conductivity and salt diffusion coefficient of PEO18LiTFSI at 60 °C were dramatically enhanced by addition of TEGDME. The composite polymer electrolyte of PEO18LiTFSI-2TEGDME exhibited a quite low stable interface resistance with lithium metal of 85 Ω•cm2 after 28 days and a low over-potential for lithium plating and striping.