In summary, this work has shown the

In summary, this work has shown the possibility to use the cold sintering process (CSP) to densify a proton refractory electrolyte material with incongruent dissolution issue (BCZY). Different parameters have been optimized and the electrolyte material was successfully cold sintered leading to a high relative density of 83 %, at low temperature equal to 180 °C under 375 MPa using 5 % wt of water. Compared to the 63 % relative density of the "dry" pressed specimen, this result shows the power of the CSP technique. Subsequent annealing at temperature lower than that of the traditional sintering (1200℃ instead of 1400℃) further improves the relative density which reaches 94%, and remarkably increases the total conductivity to 4 10−2 S. cm−1 at 700 °C by mostly increasing the grain boundary conductivity. In contrast, the grain conductivity exhibits a small variation in accordance with the lack of structural change confirmed by X-ray powder diffraction. The process demonstrated here can offer opportunities to manufacture in one-step solid oxide fuel cell by co-pressing and co-firing the electrolyte and electrodes at lowered temperature and for shorter duration.