Preparation and electrochemical performance of Pr_2Ni_(0.6)Cu_(0.4)O_4 cathode materials for intermediate-temperature solid oxide fuel cells

摘要

Cathode material Pr_2Ni_(0.6)Cu_(0.4)O_4 (PNCO) for intermediate-temperature solid oxide fuel cells (IT-SOFCs) is synthesized by a glycine-nitrate process using Pr_6O_(11), NiO, and CuO powders as raw materials. X-ray diffraction analysis reveals that nanosized Pr_2Ni_(0.6)Cu_(0.4)O_4 powders with K2NiF_4-type structure can be obtained from calcining the precursors at 1000℃ for 3 h. Scanning electron microscopy shows that the sintered PNCO samples have porous microstructure with a porosity of more than 30% and grain size smaller than 2μm. A maximum conductivity of 130S cm~(-1) is obtained from the PNCO samples sintered at 1050℃. A single fuel cell based on the PNCO cathode with 30 μm Sm_(0.2)Ce_(0.8)0_(1.9) (SCO) electrolyte film and a 1 mm NiO-SCO anode support is constructed. The ohmic resistance of the single Ni-SCO/SCO/PNCO cell is 0.08Ωcm~2 and the area specific resistance (ASR) value is 0.19 Ωcm~2 at 800℃. Cell performance was also tested using humidified hydrogen (3% H_2O) as fuel and air as oxidant. The single cell shows an open circuit voltage of 0.82 V and 0.75 V at 700℃ and 800℃, respectively. Maximum power density is 238mWcm~(-2) and 308mWcm~(-2) at 700℃ and 800℃, respectively. The preliminary tests have shown that Pr_2Ni_(1-x)CuxO_4materials can be a good candidate for cathode materials of IT-SOFCs.