Enhanced cathodic activity by tantalum inclusion at B-site of La_0.6Sr_0.4Co_0.4Fe_0.6O₃ based on structural property tailored via camphor-assisted solid-state reaction

Lanthanum strontium cobalt ferrite (LSCF) is an appreciable cathode material for solid oxide fuel cells (SOFCs), and it has been widely investigated, owing to its excellent thermal and chemical stability. However, its poor oxygen reduction reaction (ORR) activity, particularly at a temperature of ≤ 800 ℃, causes setbacks in achieving a peak power density of > 1.0 W·cm^-2, limiting its application in the commercialization of SOFCs. To improve the ORR of LSCF, doping strategies have been found useful. Herein, the porous tantalum-doped LSCF materials (La_0.6Sr_0.4Co_0.4Fe_0.57Ta_0.03O₃ (LSCFT-0), La_0.6Sr_0.4Co_0.4Fe_0.54Ta_0.06O₃, and La_0.6Sr_0.4Co_0.4Fe_0.5Ta_0.1O₃) are prepared via camphor-assisted solid-state reaction (CSSR). The LSCFT-0 material exhibits promising ORR with area-specific resistance (ASR) of 1.260, 0.580, 0.260, 0.100, and 0.06 Ω·cm² at 600, 650, 700, 750, and 800 ℃, respectively. The performance is about 2 times higher than that of undoped La_0.6Sr_0.4Co_0.4Fe_0.6O₃ with the ASR of 2.515, 1.191, 0.596, 0.320, and 0.181 Ω·cm² from the lowest to the highest temperature. Through material characterization, it was found that the incorporated Ta occupied the B-site of the material, leading to the enhancement of the ORR activity. With the use of LSCFT-0 as the cathode material for anode-supported single-cell, the power density of > 1.0 W·cm^-2 was obtained at a temperature < 800 ℃. The results indicate that the CSSR-derived LSCFT is a promising cathode material for SOFCs.