On demand micro-fuel-droplets supply system for self-sustained direct methanol fuel cells

In this paper, a micro droplets system fuel supply method was used in direct methanol fuel cells (DMFCs) by PZT actuation. The system was easily assembled and tested without large energy consumption. Compared to the circulatory system, microdroplets system, could greatly improve power density by at same condition. The electrochemical tests showed that it enables the usage of higher concentration methanol fuel (5M) of micro droplets system relative to normal circulatory flow system (2M), resulting in a higher peak power density at 32.5mW·cm^-2 than that (20.5mW·cm^-2) of the circulatory system at constant voltage mode. An automatic feedback scheme is applied to incorporate the accuracy of micro droplets spray and control of voltage drop of DMFCs for keeping high efficient fuel usage and power density.