Abstract
Recent fundamental studies have indicated the key requirement of low water crossover through the electrolyte membrane in order to enable the use of highly concentrated methanol in direct methanol fuel cells for portable electronics applications. In this paper, we shall demonstrate a single cell operated at 60oC with direct feed of methanol concentration ranging from 15M to pure methanol, while still achieving the power density of 60 mW/cm2 at 0.4V. Results of surprisingly low methanol and water crossover through a thin membrane, Nafion 112, will be reported and the interplay of water and methanol crossover will be discussed. Various components enabling such high cell performance and low crossover of water and methanol will be described, including fabrication and characterization of membrane-electrode assembly based on thin membranes (e.g. N112), methanol resistant anode structures, and cathode structures that control water crossover from the DMFC anode to the cathode.