especially the degradation mechanisms that occur in the fuel cell's different components and the relative contribution of each component’s degradation to the degradation of the entirefuel cell. However, such understanding is required for PEMFC developers to develop new materials that last longer but are not prohibitively expensive. As mentioned, in the past few years, much progress has been made in understanding how the polymer electrolyte membrane and platinum electrocatalyst degrade and the carbon supports corrode.