Novel solid acid fuel cell based on a superprotonic conductor Tl3H(SO4)2

We have fabricated a fuel cell based on a superprotonic conductor, a Tl3H(SO4)2 crystal, and have measured the electrical properties of this fuel cell. It is found that the open-circuit voltage in the fuel cell based on the Tl3H(SO4)2 crystal increases by supplying H2 fuel gas and typically becomes 0.83 V. Moreover, we have observed that the cell voltage decreases with increasing current density, as observed in fuel cells such as proton exchange membrane fuel cell, solid oxide fuel cell, etc. These results indicate that it is possible to use the Tl3H(SO4)2 crystal as the electrolyte of a solid acid fuel cell. In addition, we suggest that the selection of the electrode and the preparation of the very thin electrolyte are extremely important to achieve high-efficiency of power generation of this fuel cell.