• Energy Research

The overpotentials of the oxygen reduction on perovskite oxide catalysts were significantly reduced simply by mixing the catalyst particles with polypyrrole/carbon composites (pPy/C).

We demonstrate excellent performance and durability at intermediate temperatures (500–650 °C) upon reversible operation of an electrochemical cell incorporating a proton-permeable, high-activity mixed conducting oxide as the air electrode, a highly proton-conductive and chemically stable perovskite oxide as the electrolyte, and a composite of Ni and the electrolyte as the fuel electrode.

Over the past several years, important strides have been made in demonstrating protonic ceramic fuel cells (PCFCs). Such fuel cells offer the potential of environmentally sustainable and cost-effective electric power generation. However, their power outputs have lagged behind predictions based on their high electrolyte conductivities. Here we overcome PCFC performance and stability challenges by employing a high-activity cathode, PrBa_(0.5)Sr_(0.5)Co_(1.5)Fe_(0.5)O_(5+δ) (PBSCF), in combination with a chemically stable electrolyte, BaZr_(0.4)Ce_(0.4)Y_(0.1)Yb_(0.1)O_3 (BZCYYb4411). We deposit a thin dense interlayer film of the cathode material onto the electrolyte surface to mitigate contact resistance, an approach which is made possible by the proton permeability of PBSCF. The peak power densities of the resulting fuel cells exceed 500 mW cm^(−2) at 500 °C, while also offering exceptional, long-term stability under CO_2.