Fuel cell reactors are the most conventional way of converting “green” hydrogen or methanol into electrical energy, and as such are central to Germany’s energy transition. A special research unit called CAN at Fraunhofer Institute for Applied Polymer Research (IAP) has therefore been working on a variety of new catalyst materials to improve the performance and consistency of fuel cell (FC) reactions.
The problem is that the quality and composition of the catalyst materials currently used in FCs varies greatly, which contributes to losses in efficiency and inconsistent results. In the IAP’s HiKAB project, which is funded by the German Federal Ministry for Economic Affairs and Energy, scientists hope to eliminate these deficiencies.
Christoph Gimmler, overseeing CAN at the Fraunhofer IAP, explains how they are achieving it: "We have converted the batch process into a continuous manufacturing process. We rely on a bottom-up process – building up the nanoparticles atom by atom. In this way, we cannot only produce nanoparticles with consistent, high quality via synthesis guidance, but also selectively adjust the size, type and composition of the catalyst particles," he says.
In the special reactor built by his team, the synthesis process runs continuously, especially at the critical nucleation phase – which has been separated spatially and temporally from the growth phase to allow for more control over reaction temperatures and therefore greater reproducibility. Furthermore, the platinum element of the catalyst has been replaced (in part) with a less expensive material, which not only has improved material costs but is also proving to be more efficient and durable.
The researchers have tested the new catalysts in methanol fuel cells with promising results. The next step is to analyse how much the new materials will save in costs and to test them in hydrogen fuel cells.