Recovery of Platinum Catalyst and Polymer Electrolyte from Used Small Fuel Cells by Particle Separation Technology

Abstract

There are several conventional methods for recycling the membrane electrode assemblies (MEA) found in fuel cells. There are chemical techniques that deal with MEAs in bulk, including a method that dissolves the electrolyte film and a method that recovers the catalyst as a residue after incinerating it harmlessly. There are also physical techniques where the electrodes are detached from the MEA one by one. The former approach has a tendency to ignore the recovery of electrolyte film. Moreover, consideration should be given to the fact that the environmental load increases because it is a high-temperature and high-pressure technique that uses a large quantity of chemicals. The target of the latter approach is mainly on-vehicle fuel cells, and in many cases it is unsuitable for the mass processing of the MEAs on fuel cells used in mobile equipment, which are smaller than the above cells. A physical method that detaches the electrodes in organic solvents, which was an early development, offers a promising way to recover both electrodes and electrolyte films, and it can be used to deal with many small MEAs simultaneously. However, it has been pointed out that it is difficult to reuse the recovered electrolyte films, which are deformed and degraded when this method is used. In this study, the individual recovery of electrodes, which include a platinum group metal (PGM) catalyst, and the electrolyte films from MEAs on fuel cells used in mobile equipment, has been studied by using a milder organic solvent so that the deformation and deterioration of the electrolyte film are minimized.