High‐performance protonic ceramic fuel cells with electrode‐electrolyte composite cathode functional layers

This study reports the enhanced performance of protonic ceramic fuel cells by adopting electrode-electrolyte cathode functional layers (CFLs). PrBa0.5Sr0.5Co1.5Fe0.5O5+δ (PBSCF) and BaZrxCe0.8−xY0.1Yb0.1O3−δ (BZCYYb) were used as cathode and electrolyte materials, respectively. Thin-film CFLs comprising PBSCF and BZCYYb composites were inserted between the electrode and the electrolyte. Power output in the cells with CFLs was enhanced by approximately 4% to 20% at a temperature range of 450°C to 550°C, compared to those without CFLs. Impedance analysis confirmed that the polarization electrode resistance significantly reduced with the adoption of CFLs. The extended interface between the cathode and electrolyte in the CFLs was considered to have contributed to the reduced electrode impedance. The distribution of relaxation times analyzed by fitting the impedance data revealed the charge transfer and proton incorporation steps along with the PBSCF/BZCYYb interface in CFLs as the main contribution to the electrode performance enhancement in cathodic polarization reactions.