The Australian Nuclear Science and Technology Organisation (ANSTO) has collaborated with researchers at the University of Queensland in Australia, and Shandong University and Nanjing Tech Universities in China on research investigating the possible synergistic effects of a new perovskite cathode material for a low-temperature solid-oxide fuel cell (LT-SOFC) that demonstrates impressive and stable electrochemical performance below 500 °C.

Solid-oxide fuel cells (SOFC) convert the chemical energy in fuel into electricity directly by the oxidation of the fuel. These cells are considered to be highly efficient, exhibit long-term stability, produce low emissions, and are relatively low cost.

Researchers at MIT tackled the known problem of degradation suffered when perovskite oxides, promising candidates for electrodes in energy conversion devices like fuel cells, are exposed to water or gases such as oxygen or carbon dioxide at elevated temperatures.

The scientists explain that this degradation occurs as the surfaces of these perovskites get covered up by a strontium oxide'related layer, and this layer is insulating against oxygen reduction and oxygen evolution reactions, which are critical for the performance of fuel cells, electrolyzers and thermochemical fuel production. This layer on the electrode surface is detrimental to the efficiency and durability of the device, causing the surface reactions to slow down by more than an order of magnitude.

Researchers at Purdue University have found that nickel-based perovskites have exceptional properties for use as solid electrolytes in fuel cells. Unlike conventional electrolytes, these nickel-based perovskites are chemically stable in the fuel cell's environment, which could lead to higher performing and longer lasting fuel cells.

Schematic of the perovskite samarium nickelate (SNO)-electrolyte solid-oxide fuel cell.

Solid-oxide fuel cells are considered as one of the most efficient types of fuel cells. They typically use polymers or ceramics as an electrolyte, but finding an effective solid electrolyte'one that conducts protons but blocks electrons'at low operating temperatures of 300'500°C has been a challenge. Most materials, when exposed to low pressure, start to lose oxygen and become electron conductors; The electrolyte separator becomes leaky so it can short circuit the fuel cell or it can start to crack and allow fuel to mix with oxygen.