Low-temperature fabrication of protonic ceramic fuel cells with BaZr0.8Y0.2O3−δ electrolytes coated by aerosol deposition method

•Highly Y-doped BaZrO3 (BZY20) powders for aerosol deposition (AD) were synthesized.•BZY-electrolyte cell was successfully fabricated by commercially-available AD.•Cell sintered at low temperature, 1200 °C, showed considerably high power density.•Increase of power density was due to increase of electrical conductivity of BZY.•Polarization resistance was larger than Ohmic resistance at or below 600 °C.

To overcome the difficulties of sintering yttrium (Y)-doped barium zirconate (BZY), an aerosol deposition (AD) method is suggested as an attractive alternative since it produces dense BZY films in commercially large areas with high deposition efficiency at low temperature. In this study, highly Y-doped BZY powder for use in AD method was synthesized successfully without use of sintering additives; the process involves a series of careful preparation processes including pre-doping of Y, high-energy milling, and calcination with an atmospheric powder which maintains controlled BaO vapour pressure. It is noted that Y-doping of BaZrO3 in starting powder is important in the AD method. The increased conductivity of BZY electrolyte film using this powder resulted in relatively small Ohmic resistance (∼0.5 Ω cm2 at 700 °C) and good cell performance (∼180 mW cm−2 at 700 °C). These are one of the best performance among the reported values of cells that employ BaZr0.8Y0.2O3−δ (or BZY20) as an electrolyte. The high performance is also remarkable although the firing temperature of this cell (1200 °C) is much lower than those (≥1400 °C) shown in literature studies. The performance can be further improved with appropriate choice of cathode and anode materials.