Comparison of solvation behavior and ionic conductance of A-site Sr and Ca doped and B-site Cu doped LaAlO3

Enhancing ionic conductivity while reducing the sintering temperature remains a critical challenge in solid oxide fuel cell (SOFC) research. In this study, we first employed Cu doping at the B-site to lower the sintering temperature and identify an optimal doping ratio of 10 mol% LaAl_0.9Cu_0.1O_3-δ(LAC10). Density functional theory (DFT) calculations further indicate that LAC10 exhibits favorable ionic conduction characteristics. Building upon this Cu-doped matrix, we systematically investigated the effects of A-site substitution with divalent cations (Ca²⁺, Sr²⁺) on microstructure and electrochemical performance. Compared to undoped LaAlO₃ (9.82 * 10^-6 S·cm⁻¹) and Cu-only LAC10 (1.05 * 10^-2 S·cm⁻¹), the La_0.8Sr_0.2Al_0.9Cu_0.1O_3-δ composition demonstrates significantly enhanced ionic conductivity (1.44 * 10^-2 S·cm⁻¹) and a relatively low activation energy of 0.481 eV. Moreover, a single cell employing this electrolyte achieved a peak power density of 611.76 mW·cm⁻² at 700°C. These results demonstrate that the combined incorporation of Sr and Cu into the LaAlO₃ lattice substantially improves SOFC-relevant properties, making La_0.8Sr_0.2Al_0.9Cu_0.1O_3-δ a promising electrolyte candidate.