A proton conductor of the present disclosure contains a compound represented by a chemical formula BaZrYbCuO. In the chemical formula. 0.95≤a≤1.05, 0.1≤x≤0.4.0.01

What is provided are a proton-conducting solid electrolyte which can exhibit high proton conductivity and stability in a low-temperature range and a medium-temperature range, an electrolyte layer formed of the proton-conducting solid electrolyte, and a bat...

The electrolyte material comprises an electronically insulating oxide of a base metal and at least one additional metal or oxide of an additional metal, which enhances the base metal with ionic conductivity. According to the invention, the electrolyte mate...

The electrolyte sheet for solid oxide fuel cell of the present invention has different surface roughnesses between the peripheral region and the region other than the peripheral region at least on one side. The surface roughness Ra(b) in the peripheral reg...