Thin film solid oxide fuel cell using a pinhole-free and dense Y-doped BaZrO3

•The proton conducting material (Y-doped BaZrO3) is utilized as the electrolyte.•The thin film solid oxide fuel cells are fabricated via fully vacuum processes.•The peak power density of 44 mW/cm2 is measured at 450 °C.

The proton conductor Y-doped BaZrO3 (BZY) is a promising electrolyte material for solid oxide fuel cells operating in the low-temperature regime of 300–500 °C. We characterize BZY thin films with different thicknesses and oxygen pressures via a pulsed laser deposition method. The surface morphology is porous and coarse when an oxygen pressure of 13,300 Pa is applied during the deposition, but a dense BZY thin film is acquired when the oxygen pressure is 2600 Pa. As a result, a thin-film solid oxide fuel cell with fully dense BZY is fabricated, resulting in a peak power density of 44 mW/cm2 at 450 °C.