Structure Design and Implementation of the Passive μ-DMFC

A dual-chamber anode structure is proposed in order to solve two performance problems of the conventional passive micro direct methanol fuel cell (μ-DMFC). One of the problems is the unstable performance during long time discharge. The second problem is the short operating time. In this structure, low concentration chamber is filled with methanol solution with appropriate concentration for the μ-DMFC. Pure methanol in high concentration chamber diffuses to the low concentration chamber to keep the concentration of methanol solution suitable for long-term discharge of μ-DMFC. In this study, a Nafion-Polytetrafluoroethylene (PTFE) composite membrane is inserted between the two chambers to conduct pure methanol. The experimental results during long-term discharge show that the stable operating time of passive μ-DMFC increases by nearly 2.3 times compared to a conventional one with the same volume. These results could be applied to real products.