The fuel cell represents a promising way of generating electrical power from a variety of fuels, which converts the chemical energy of a fuel and oxidant directly into electrical power. Polymer electrolyte membrane fuel cells (PEMFC) are an environment-friendly and high efficient alternative of conventional energy sources [1-2].
A key component of PEMFC is a proton conducting membrane. It has two main functions – providing of proton transfer from anode to cathode and separation of fuel and oxidizing agent .
The PEMFC can be operated using various types of fuel, including hydrogen, natural gas, biogas, alcohols, and other organic compounds, the oxidizing agent of is usually oxygen of the air .
Commercially available membranes, such as Nafion, have good mechanical properties and high conductivity. However, the high cost of the membranes leads to an increase in the cost of the fuel cell . There is also an urgent need to dispose of the membrane after the end of its life cycle. The use of more efficient and cheaper proton-exchange membranes in PEMFC will lead to cost reduction and widespread application of these power sources. The use of biodegradable components in the composition of the membranes will contribute to their more efficient disposal. Therefore, the objective of this work is the synthesis and study of new proton-exchange membrane materials for sustainable energy conversion and fuel cell applications with eco-friendly process.
The synthesis of proton-exchange membranes was carried out in accordance with the principles of "green chemistry" using a biodegradable polymer – polyvinyl alcohol. Sulfosuccinic acid was used as a crosslinker. The membranes were doped with zeolites of ZSM and BEA types. Proton conductivity of synthesized membranes was measured by impedance spectroscopy in the temperature range of 30-80 C. Ion exchange capacity was measured by the back titration method (GOST 17552-72).
A convenient method for the synthesis of proton-exchange membranes based on polyvinyl alcohol, sulfosuccinic acid and zeolites was developed and main physicochemical characteristics of the samples were investigated. The samples obtained are characterized by proton conductivity of the order of 10–3 –10–2 S cm-1. The membrane with the addition of zeolite BEA has lower activation energy for the proton transfer process than the sample with ZSM zeolite - 18.56 and 26.17 kJ / mol, respectively. Water absorption of the synthesized samples is 19.5% and 40% for samples with the addition of zeolites ZSM and BEA, respectively. The ion exchange capacity of the membrane sample with zeolite ZSM additive was 1.22 mg • eq / g, and for the membrane doped with zeolite BEA - 1.28 mg • eq / g.
The results show that the obtained protonconductive membranes possess similar physicochemical characteristics compare with commercial Nafion membranes ("DuPont", USA). The advantage of the developed membranes is lower production cost and environmental friendliness. In this regard, the proposed membranes are promising materials for use in PEMFC. The use of fuel cells as sources of electricity will significantly reduce the harmful effects on the environment and increase the performance properties of energy systems based on them.
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|Affiliation of speaker||Irkutsk National Research Technical University|
|Publication||Journal of Cleaner Production|
|Position of speaker||post-graduate student|