Ceramics-Silikáty

The choice of cathode material critically affects the performance of intermediate-temperature proton-conducting solid oxide fuel cells (H^⁺-SOFCs). A key challenge is the high polarization resistance associated with water formation at the cathode. In this work, LiCoO₂-based cathodes were doped to improve triple conduction (H^⁺/O^²⁻/e^⁻). LiCo_₀.₈M_₀.₂O₂ (LCMO; M = Ca or Zr) were prepared using the glycine-nitrate combustion method. At 800 °C, LiCo_₀.₈Ca_₀.₂O₂ (LCCO) and LiCo_₀.₈Zr_₀.₂O₂ (LCZO) exhibited high electrical conductivities of 977.0 and 1094.5 S·cm^⁻¹, respectively, which exceed the typical minimum requirement for SOFC cathodes. The area-specific resistance (ASR) in dry air was 1.7441 Ω·cm² for LCCO and 2.470 Ω·cm² for LCZO. LCZO exhibited slightly better ASR values (3.154 Ω·cm²) in wet air compared to LCCO (3.442 Ω·cm²). Cross-sectional analysis showed excellent contact between the cathodes and the BZCY electrolyte, with no interdiffusion after sintering. After exposure to wet air, LCZO showed better dimensional stability than LCCO. These results indicate that the glycine-nitrate combustion method successfully produced well-performing LiCoO_₂-based cathodes with high electrical conductivity and good electrode-electrolyte contact. Doping with Ca and Zr clearly improved the electrical and electrochemical performance compared to the undoped material. Among the studied compositions, the Zr-doped cathode (LCZO) demonstrated improved dimensional stability, while Ca-doped cathode (LCCO) showed lower ASR under most conditions; overall, both compositions exhibit promising but still moderate electrochemical performance.