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Fuel Cells: Polymers, Platinum and a Poster Prize

02 May 2016

Fuel cells are an important area of research at the Heinz Maier-Leibnitz Zentrum (MLZ), where JCNS operates its largest outstation. Polymer electrolyte fuel cells convert hydrogen and oxygen into electrical energy. This process takes place at the heart of the fuel cell in the membrane-electrode unit. The membrane of this unit is coated on both sides with electrodes of nano-porous carbon and platinum particles. This type of fuel cell is very versatile, but has serious disadvantages: cooling and water management are complex procedures and the catalyst is sensitive to carbon monoxide. These disadvantages are eliminated in the so-called high-temperature variant (HT-PEFC), which operates at temperatures of 160-180 °C.

Fuel CellsThe Jülich instrument SPHERES is one of the best backscattering spectrometers in the world, suitable, for example, for use in high-resolution proton diffusion measurements.
Copyright: Astrid Eckert / TUM

To find out how to improve the efficiency of the catalytic layers on the HT-PEFC membranes by optimizing their composition, scientists at JCNS together with colleagues from the Institute of Energy and Climate Research (IEK-3) have examined proton diffusion in more detail using quasi-elastic neutron scattering (QENS). “An important consideration here is the proton transfer in the phosphoric acid present in the electrode layer, and the connection this has with the catalyst’s platinum concentrations. QENS at the SPHERES instrument provides an ideal method to study this in detail,” explained Dr. Marina Khaneft, Instrument Scientist at the JCNS outstation at the MLZ.

The researchers found that proton diffusion, which determines the conductivity in the system, is dependent upon the catalyst concentration. Phosphoric acid appears to be “caught” by the platinum particles. Results show that with neutron scattering, it is possible to study how fuel cells function in such detail which is not accessible using other techniques. Consequently, the individual components of the fuel cell can thus be optimized for longer cell life and better efficiency.

An in-depth report has recently been published online. In summer 2015, Khaneft had already been awarded the poster prize at the 5th European Fuel Cell Forum (EFCF2015) in Lucerne, Switzerland, for the presentation of this research work.

Fuel CellsDr. Marina Khaneft was awarded the Christian Friedrich Schönbein Prize for Best Poster at the European Fuel Cell Forum 2015.
Copyright: EFCF

Original publication:
M. Khaneft et al.,
Structure and Proton Dynamics in Catalytic Layer of HT‐PEFC,
Fuel Cells 2016, DOI: 10.1002/fuce.201500167

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