Efficient water recirculation for portable direct methanol fuel cells using electroosmotic pumps

초록

We present an efficient water recirculation method for air-breathing direct methanol fuel cells (DMFC) by utilizing so-called electroosmotic (EO) pumps. The fuel management system includes three EO pumps for the delivery of methanol solution, pure methanol, and pure water, respectively. Water recirculates from the fuel cell back to the fuel supply stream with the aid of these pump systems. We characterized the performance of the air-breathing DMFC for 2 M and 4 M methanol solutions using a syringe pump and EO, pumps, respectively. The DMFC performance is similar for both types of pumps as long as the EO pump operates with the applied voltage of 6 V or higher. The maximum net power density (fuel cell power generation minus pump power consumption) was 50 mW cm(-2) for 2 M methanol solution and the applied pump potential of 8 V. The minimum parasitic power ratio (pump power consumption divided by fuel cell power generation) was merely 2.1% for 4 M methanol solution and the applied pump potential of 6 V. We successfully demonstrated that the air-breathing DMFC integrated with the EO pumps operated in a stable condition in 1-h galvanostatic measurement. (C) 2012 Elsevier B.V. All rights reserved.

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