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

[1] We present an assessment of biofuel use and agricultural field burning in the developing world. We used information from government statistics, energy assessments from the World Bank, and many technical reports, as well as from discussions with experts in agronomy, forestry, and agro-industries. We estimate that 2060 Tg biomass fuel was used in the developing world in 1985; of this, 66% was burned in Asia, and 21% and 13% in Africa and Latin America, respectively. Agricultural waste supplies about 33% of total biofuel use, providing 39%, 29%, and 13% of biofuel use in Asia, Latin America, and Africa, and 41% and 51% of the biofuel use in India and China. We find that 400 Tg of crop residues are burned in the fields, with the fraction of available residue burned in 1985 ranging from 1% in China, 16–30% in the Middle East and India, to about 70% in Indonesia; in Africa about 1% residue is burned in the fields of the northern drylands, but up to 50% in the humid tropics. We distributed this biomass burning on a spatial grid with resolution of 1 1, and applied emission factors to the amount of dry matter burned to give maps of trace gas emissions in the developing world. The emissions of CO from biofuel use in the developing world, 156 Tg, are about 50% of the estimated global CO emissions from fossil fuel use and industry. The emission of 0.9 Pg C (as CO2) from burning of biofuels and field residues together is small, but nonnegligible when compared with the emissions of CO2 from fossil fuel use and industry, 5.3 Pg C. The biomass burning source of 10 Tg/yr for CH4 and 2.2 Tg N/yr of NOx are relatively small when compared with total CH4 and NOx sources; this source of NOx may be important on a regional basis. INDEX TERMS: 1610 Global Change: Atmosphere (0315, 0325); 1803 Hydrology: Anthropogenic effects; 1615 Global Change: Biogeochemical processes (4805); KEYWORDS: biofuel use, global biofuel burning, agricultural waste burning, biofuel emissions

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An assessment of biofuel use and burning of agricultural waste in the developing world

Hydrogen: Trends, production and characterization of the main process worldwide

In a time of unprecedented change in environmental, geopolitical and socio-economic world affairs, the search for new energy materials has become a topic of great relevance. Sodium borohydride, NaBH 4 , seems to be a promising fuel in the context of the future hydrogen economy. NaBH 4 belongs to a class of materials with the highest gravimetric hydrogen densities, which has been discovered in the 1940s by Schlesinger and Brown. In the present paper, the most relevant issues concerning the use of NaBH 4 are examined. Its basic properties are summarised and its synthesis methods are described. The general processes of NaBH 4 oxidation, hydrolysis, and monitoring are reviewed. A comprehensive bibliometric analysis of the NaBH 4 publications in the energy field opens the discussion for current perspectives and future outlook of NaBH 4 as an efficient energy/hydrogen carrier. Despite the observed exponential increase in the research on NaBH 4 it is clear that further efforts are still necessary for achieving significant overchanges.

Sodium borohydride as a fuel for the future

A direct borohydride fuel cell (DBFC) is a device that converts chemical energy stored in borohydride ion (BH4−) and an oxidant directly into electricity by redox processes. Usually, a DBFC employs an alkaline solution of sodium borohydride (NaBH4) as fuel and oxygen or hydrogen peroxide as oxidant. DBFC has some attractive features such as high open circuit potential, ease of electro-oxidation of BH4− on non-precious metals such as nickel, low operational temperature and high power density. The DBFC is a promising power system for portable applications. This article discusses prominent features of DBFC, reviews recent developments in DBFC research, and points out future directions in DBFC research.

Halil Ibrahim Sarac

Papers

Effects of operation conditions on direct borohydride fuel cell performance

Influences of sodium borohydride concentration on direct borohydride fuel cell performance

Improving the direct borohydride fuel cell performance with thiourea as the additive in the sodium borohydride solution

Sugar cane as an alternative energy source for Turkey

An experimental study for H2S and CO2 removal via caustic scrubbing system