%0 Journal Article
%K Electrochemical electrodes
%K Catalysts
%K Cobalt compounds
%K Alkaline fuel cells
%K Lanthanum compounds
%A Churl Kyoung Lee
%A Kathryn A Striebel
%A Frank R McLarnon
%A Elton J Cairns
%B Journal of The Electrochemical Society
%D 1997
%N 11
%P 3801-3806
%R 10.1149/1.1838095
%T Thermal Treatment of La<sub>0.6</sub>Ca<sub>0.4</sub>CoO<sub>3</sub> Perovskites for Bifunctional Air Electrodes
%V 144
%! J. Electrochem. Soc.
%X <p>The perovskite La<sub>0.6</sub>Ca<sub>0.4</sub>CoO<sub>3</sub> has been of interest as a bifunctional electrocatalyst for the bifunctional air electrode. The calcination and subsequent cooling steps in the amorphous citrate precursor (ACP) process have been optimized to prepare La<sub>0.6</sub>Ca<sub>0.4</sub>CoO<sub>3</sub> powders with high surface area, and consequently improved electrocatalytic performance in an air electrode. The surface area of the final powder depends on the thermal treatment and the surface area increases with increasing the cooling rate. A sample quenched rapidly from 650°C had a surface area of 33 m<sup>2</sup>/g, which is more than double the value obtained with a slower cooling rate. Polytetrafluorene-ethylene (PTFE) bonded gas diffusion electrodes loaded with La<sub>0.6</sub>Ca<sub>0.4</sub>CoO<sub>3</sub> catalysts prepared by the ACP method show good bifunctional performance. An electrode loaded with only 10 mg/cm<sup>2</sup> of powder prepared by quenching from 650°C showed the best bifunctional performance, i.e., 280 mA/cm<sup>2</sup> for oxygen reduction and 300 mA/cm<sup>3</sup> for the oxygen evolution, at 0.6 and 1.6 V vs. RHE, respectively. This performance compares well with results from lower area La<sub>0.6</sub>Ca<sub>0.4</sub>CoO<sub>3</sub> at much higher loadings.</p>