Recent advances in understanding of mass transfer phenomena in direct methanol fuel cells operating with concentrated fuel

Running direct methanol fuel cells (DMFC) with concentrated fuel is desirable to maximize the specific energy of the fuel cell system and to improve the performance by mitigating the water flooding problem associated with diluted methanol operation. This article provides a comprehensive review of recent advances in understanding mass transport phenomena in DMFCs operating with concentrated fuel. The review starts with elaborating the key issues of mass transport of reactants and products associated with highlyconcentrated methanol operation, followed by summarizing and discussing past experimental and numerical investigations into the effects of the membrane electrode assembly (MEA) design, flow field structure and operating conditions on the mass transport characteristics and the cell performance. Finally, future opportunities and challenges regarding the mass transport of DMFCs operating with concentrated fuel are also highlighted.