Solid electrolyte and fuel cell, hydrogen pump, oxygen concentration sensor and water vapor concentration sensor using the same

摘要

A solid electrolyte of the present invention has a perovskite structure including an alkaline earth metal site, a rare earth element site, and oxygen, wherein barium (Ba) exists in the alkaline earth metal site, and praseodymium (Pr) and at least one other rare earth element exist in the rare earth element site. This solid electrolyte has excellent proton conductivity and oxide ion conductivity and shows high electrical conductivity in a temperature range of 400 to 700.degree.C. This solid electrolyte is applied to construct fuel cells, a hydrogen pump, an oxygen concentration sensor, and a steam concentration sensor, which are favorably driven in the above temperature range.