Proton Conductors And Their Application

There has been a great deal of scientific and technological interest in developing improved battery systems for use in portable electronic devices, backup power systems to electric vehicles. Solid-state protonic conductors have also extensively been used in the following electrochemical devices (i) gas sensors, (ii) electro-chromic displays, and (iii) fuel cells. However, relatively less attention has been paid towards their application from solid state battery point of view. Compared to others like lithium and silver solid-state batteries, these are very simple to fabricate and economic. A solid proton conductor of crystalline / amorphous form allows the passage of electrical current through the bulk material exclusively by movement of protons, H+. The electrochemical transfer of H-2 from one electrode to the other has taken place due to applied potential difference to the electrodes when proton conductor is placed in between the two noble metals / hydrogen. The H+, H3O+, OH- or NH4+ have been the known conducting species of this class. Some of the reported good proton conductors have been acidic and basic hydrates like, HUP, HUAS, PSA, PMA, etc. In general, the charge transfer in solid by motion of protons has been the major problem in the field of proton conduction. So, it has become all the more necessary to understand a clear-cut difference between electron, ion and proton conduction, and also to obtain convincing proof of charge transfer by proton species. In this paper, a brief work on proton conductors and solid-state battery is presented.