Another Chance for Classic AFCs? Experimental Investigation of a Cost‐Efficient Unitized Regenerative Alkaline Fuel Cell, Using Platinum‐Free Gas Diffusion Electrodes

The big challenge of global phase‐down of carbon dioxide emissions leads us to alternatives in storing electric energy from renewable sources. For the worldwide use of batteries and fuel cells very high amounts of precious electrode materials are needed. Batteries require rare earth metals and environmentally harmful Lithium, PEM fuel cells require noble platinum and iridium. Thus, an economical and eco‐friendly alternative to lithium‐ion‐batteries should be found, especially for the use in domestic homes. In the on‐hand work, a well‐known type of fuel cell is revised and considered in the new context of global material usage. Therefore, an alkaline fuel cell with the classic design of an electrolyte gap in‐between the electrodes is observed. Gas‐diffusion‐electrodes are used, based on Raney‐nickel. Results are given for different catalysts: Raney‐nickel, Raney‐silver, manganic‐oxide, carbon and ruthenium. For the analysis current‐voltage‐characteristics, chronopotentiometry and SEM micrographs are used. The results are discussed in comparison to a unitized reversible PEM fuel cell. At low current density, the alkaline cell is obtaining round‐trip efficiencies close to 70%, while the PEM cell achieves only 60% efficiency. With Silver‐catalyst clear higher efficiencies up to 80% are presentable. The PEM fuel cell shows obvious better performance at high current densities.