“…Their applications in these devices require high energy density and the performance should be comparable to that of large systems. In general, among the existing types of fuel cells, proton exchange membrane fuel cell (PEMFC) [1,2] and direct methanol fuel cell (DMFC) [3,4] are considered to be suitable candidates for miniature fuel cells because of their low operating temperature, high power density, and feasibility for miniaturization. While recently, a novel design of miniature fuel cell based on microfluidic devices has emerged as another type of miniature fuel cells.…”