The sintering temperature effect on electrochemical properties of Ce0.8Sm0.05Ca0.15O2- (SCDC)-La0.6Sr0.4Co0.2Fe0.8O3- (LSCF) heterostructure pellet

Recently, semiconductor-ionic materials (SIMs) have emerged as new functional materials, which possessed high ionic conductivity with successful applications as the electrolyte in advanced low-temperature solid oxide fuel cells (LT-SOFCs). In order to reveal the ion-conducting mechanism in SIM, a typical SIM pellet consisted of semiconductor La0.6Sr0.4Co0.2Fe0.8O3- (LSCF) and ionic conductor Sm and Ca Co-doped ceria Ce0.8Sm0.05Ca0.15O2- (SCDC) are suffered from sintering at different temperatures. It has been found that the performance of LSCF-SCDC electrolyte fuel cell decreases with the sintering temperature, the cell assembled from LSCF-SCDC pellet sintered at 600 degrees C exhibits a peak power density (P-max) of 543mW/cm(2) at 550 degrees C and also excellent performance of 312mW/cm(2) even at LT (500 degrees C). On the contrary, devices based on 1000 degrees C pellet presented a poor P-max of 106mW/cm(2). The performance difference may result from the diverse ionic conductivity of SIM pellet through different temperatures sintering. The high-temperature sintering could severely destroy the interface between SCDC and LSCF, which provide fast transport pathways for oxygen ions conduction. Such phenomenon provides direct and strong evidence for the interfacial conduction in LSCF-SCDC SIMs.