Membranes for Electrochemical Energy Applications

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