**Conflict of interest**

The authors declare no conflict of interest.

*Proton Conductivity in Chitin System DOI: http://dx.doi.org/10.5772/intechopen.96799*

*Chitin and Chitosan - Physicochemical Properties and Industrial Applications*

improved by nearly 24 times by using the structure. In the future, it is expected that the key to practical use will be the improvement of output by chemical modification and the development of technology for producing oriented chitin at low cost.

*Schematic diagram of fuel cell using oriented chitin (left) and its i-V characteristics (right) [11].*

Since chitin functions as an electrolyte membrane for fuel cells, it has been clarified that it is a proton conductor. It was found that the presence of water molecules is very important for the appearance of proton conductivity in chitin, and that these water molecules behave like conductors in chitin hydrate to conduct protons. Furthermore, it was suggested that the orientation dependence of the proton conductivity appearing in the oriented chitin is due to the bottleneck caused by the different hydrogen bond distances with the water molecules formed in the chitin depending on the position. It was also indicated that the high proton conductivity of oriented chitin appears by increasing the number of pathways by utilizing the bottleneck and the pathway in the fiber vertical direction, which is the low activation energy pathway. When a fuel cell using the fiber direction of oriented chitin having high proton conductivity was prepared, an improvement in proton conductivity of nearly 24 times was observed. In the future, chitin orientation methods and chemical approaches are expected to provide a foothold for more practical polysaccharide-based electrolyte membranes and to clarify new value in the energy field.

Professor Yasumitsu Matsuo of Setsunan University provided appropriate advice

and research facilities in carrying out this research. I'm really thankful to you.

**174**

**4. Conclusions**

**Figure 11.**

**Acknowledgements**

**Conflict of interest**

The authors declare no conflict of interest.
