This article provides an up-to-date perspective on the use of anion-exchange membranes in fuel cells, electrolysers, redox flow batteries, reverse electrodialysis cells, and bioelectrochemical systems (e.g. microbial fuel cells). The aim is to highlight key concepts, misconceptions, the current state-of-the-art, technological and scientific limitations, and the future challenges (research priorities) related to the use of anion-exchange membranes in these energy technologies. All the references that the authors deemed relevant, and were available on the web by the manuscript submission date (30th April 2014), are included.

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Anion-exchange membranes in electrochemical energy systems

Anion exchange membranes for alkaline fuel cells: A review

Polymeric materials as anion-exchange membranes for alkaline fuel cells

https://www.engr.uvic.ca/~ndjilali/Papers/IJHE_McLean%20et%20al_2002.pdf

An assessment of alkaline fuel cell technology

Nitrogen is a fundamental constituent for all living creatures on the Earth and modern industrial society. The current nitrogen industry is largely powered by fossil fuels with huge energy consumption and carbon dioxide emission, and nitrogen pollution in surface water bodies induced by the indiscriminate discharge of industrial and domestic wastewater has become a worldwide environmental concern. Electrochemical techniques for nitrogen fixation and transformation under mild conditions are promising approaches to meet the challenge of efficiently managing and balancing the nitrogen cycle, where the rational design of advanced electrocatalysts from both structural and compositional aspects down to the nanoscale plays the most essential role. Herein, important nitrogen species including dinitrogen (N2), ammonia (NH3) and hydrazine (N2H4), their transformation processes between each other including the nitrogen reduction reaction (NRR), ammonia oxidation reaction (AOR) and hydrazine oxidation reaction (HzOR), and research progress on the development of related electrocatalysts are systematically summarized, aiming at establishing a general picture of the whole nitrogen cycle instead of a certain single reaction. Strategies combining theoretical computations and experimental optimizations are proposed to improve the catalytic performance including activity, efficiency, selectivity and stability, finally contributing to a self-sufficient and carbon-free "green" nitrogen economy.

Electrochemical nitrogen fixation and utilization: theories, advanced catalyst materials and system design.

The air depolarized cell comprises a laminated cathode assembly including an air cathode and an auxiliary cathode in combination with a layer of a thin film nonporous gas permeable membrane which is disposed with one side over the air cathode and with the opposite side having substantially unrestricted access to the atmosphere through a gas diffusion member. The nonporous membrane controls the transfer of oxygen from the ambient atmosphere to the air cathode exclusively by gas solubility with its permeability to oxygen selected to correspond to a predetermined average current density for the cell.

Air depolarized cell

A fuel cell is an electrochemical device that continues to generate electrical power as long as reactants are supplied and products are removed at properly controlled rates. An assembly of cells is required within which the conversion of chemical to electrical energy occurs; also required is a set of auxiliary components to supply the reactants and remove the products (including waste heat) under controlled steady-state conditions. In addition to the desired energy-conversion reactions, there are deleterious side reactions that can impair fuel economy. From knowledge of these factors influencing the possible reactions, and guided by principles of elementary chemical thermodynamics, the electrochemist can select optimum conditions for cell performance. It is then the job of the engineer to design auxiliary components and controlling devices to provide the electrochemical cells with the best possible approach to these optimum conditions.

Karl V Kordesch

Papers

Air depolarized cell

Hydrazine-air fuel cells. Hydrazine-air fuel cells emerge from the laboratory.

Apparatus for hydrogen generation

Porous conductive electrode having at least two zones

Fuel cell electrode