Durability and stability of vapor-feed microfluidic fuel cells, a preliminary study

Vapor-feed microfluidic fuel cell (VF-MFC) can achieve much higher energy density than conventional liquid-feed microfluidic fuel cell, but its durability and stability have never been investigated yet. In this work, a preliminary experimental study is conducted specifically on this issue. First, the long-term durability of VF-MFC is studied by consecutively discharging the cell at its peak power point for ten times in total and 5hrs for each time. It is found that the relative degradation rate for each discharge is similar, which is ~3.6%/h. Also, the cell performance keeps identical throughout the durability test. Therefore, it is concluded that no irreversible degradation such as catalyst poisoning or contact resistance increment occurs and the cell durability is satisfactory. Next, several possible mechanisms responsible for the short-term stability degradation are investigated separately, including the effect of fuel dilution, the effect of carbonate precipitation on the anode side, and the effect of water flooding on the cathode side. These issues will be further optimized in the future in order to obtain a much better discharge stability.