A novel MEA (membrane electrode assembly) structure of passive mu-DMFC (micro-direct methanol fuel cell) controls water management and decreases methanol crossover. The CNT (carbon nanotube) paper replacing CP (carbon paper) as GDL (gas diffusion paper) enhances water back diffusion which passively prevents flooding in the cathode and promotes low methanol crossover. Moreover, the unique structure of CNT paper can also enhance efficiency of oxygen mass transport and catalyst utilization. The passive mu-DMFC with CNT-MEA exhibits significantly higher performance than passive mu-DMFC with CP-MEA and can operate in high methanol concentration, showing the peak power density of 23.2 mW cm(-2). The energy efficiency and fuel utilization efficiency are obviously improved from 11.54% to 22.7% and 36.61% -4934%, respectively, and the water transport coefficient is 0.47 which is lower than previously reported passive mu-DMFC with CP. (C) 2015 Elsevier Ltd. All rights reserved.