The effects on the performance of direct methanol fuel cell(DMFC)with oxygen humidifying, oxygen preheating at the cathode and placement ways of the cell were studied. Electrochemical impedance spectroscopy (EIS) test results revealed that oxygen humidifying led to a 10.3% reduction of internal resistance and improvement of the cell performance at low temperature,but oxygen humidifying resulted in flooding in the cathode and decreased the cell performance at high temperature. Oxygen preheating could ensure temperature balance in the cathode and avoid the condensation of H2O steam produced from cathode into water,improving the mass transfer ability and then enhanced the power density of cell from 46.70 Mw/cm2 to 52.48 Mw/cm2 at 55 t, which was especially notable at higher running temperature. Four feeding patterns were designed, the vertical feeding way promoted CO2 being emitted,reduced methanol crossover and obtained the maximum performance(54.13 Mw/cm2)at lower rate of methanol.%研究阴极氧气加湿、预热及电池放置方式对直接甲醇燃料电池(DMFC)性能的影响.电化学阻抗谱(EIS)测试结果显示:氧气加湿使电池内阻降低10.3％,改善了低温运行时的电池性能；在较高温度下,氧气加湿导致阴极出现水淹,降低了电池性能；氧气预热在保证阴极温度平衡的同时,避免了产物水分遇冷凝结,改善了阴极的传质性能,电池的功率密度在55℃时从46.70 mW/cm2提高到52.48 mW/cm2；运行温度越高,氧气预热对性能的改善越显著.设计了4种进料方式,其中垂直进料方式使CO2最易排出、甲醇渗透最少,甲醇流速较低时可得到最高的功率密度(54.13 mW/cm2).
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