TAILORING THE PROPERTIES OF A-SITE SUBSTITUTED Ba_(1-x)Gd_(0.8)La_(0.2+x)Co_2O_(6-δ)

摘要

The double perovskite BaGd_(0.8)La_(0.2)Co_2O_(6-δ) (BGLC) shows excellent performance as oxygen electrode for Proton Ceramic Fuel Cells (PCFCs) and electrolyzer cells (PCEC), with polarization resistances in wet oxygen of 0.04 and 10 Ωcm~2 at 650 and 350°C, respectively [1]. Compared with other reported PCFC cathodes [2], BGLC performs better both at high and low temperature. The excellent performance of BGLC in proton ceramic cells is rationalized by a suggested partial proton conductivity at intermediate temperatures, supported by significant hydration up to 400°C observed by thermogravimetric studies. However, the chemical stability of BGLC in high steam pressures under PCEC operation remains a concern due to its highly basic A-site. Thus, tailoring the A-site stoichiometry by partial substitution of Ba with La may be a viable route for further optimizing the balance between chemical stability and electrochemical performance.