Currently, many studies on fuel cells are conducted toward the realization of a hydrogen energy society. Significantly, many investigations concerning fuel cell electrolytes of low cost and high-proton conductivity are carried out. It is also well known that biomaterials are abundant in nature and environmentally friendly materials. In this study, we have fabricated a new fuel cell using ion channel membrane as electrolytes, which are biomaterials with high ionic conductivity, and investigated their electrical properties. The squid axon is used as the ion channel electrolyte. Squid axons have often been used to study ion channels and have suitable properties as electrolytes of fuel cells. The i-V characteristics in the fuel cell using the squid axon electrolyte at 100% relative humidity. The maximum power density of the fuel cell with the ion channel membrane was 0.78 mW/cm2. Furthermore, we have obtained the result that the power of the fuel cell using the squid axon membrane remarkably decreases by blocking the ion channels using a channel blocker. These results indicate that the fuel cell using the squid axon as the electrolyte operates by the function of the ion channel. In addition, in order to investigate the relationship between proton conductivity and relative humidity, we have carried out the impedance measurement. It was found that the proton conductivity of the squid-axon electrolyte drastically increases at a relative humidity of 85% to 96%. From these results, it is deduced that higher proton conductivity of the squid-axon electrolyte above 96% relative humidity is caused by the activation of ion channels closely related to the fractionalization of water molecule clusters. These results indicate that the fuel cell using the squid-axon membrane becomes the fuel cell using the activation of the ion channel above 96% relative humidity.
Tomoki Furuseki is a Ph.D. student at Setsunan University majoring in life sciences.
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