“…Among all kinds of technologies, proton exchange membrane fuel cells (PEMFCs), directly converting chemical energy into electric energy, have gained great interests, and been regarded as potential substitutes to the future power sources due to the advantages such as zero pollution, low noise, and high energy efficiency, compared to fossil-fuel engines [1][2][3]. Moreover, the good compatibility of PEMFCs with other sustainable sources, such as solar and wind sources, expanded their application in renewable energy systems [4][5][6].…”