This research addresses the issue of particle agglomeration and a low catalytic activity in the traditional sol–gel preparation of LaNi 0.5 Co 0.5 O 3 (LNCO). A new synthetic strategy is proposed, leveraging the combination of polyvinylpyrrolidone (PVP) serving as a complexing agent and graphene nanosheet (GN) functioning as a template, successfully producing a high-activity LNCO cathode material (GN-LNCO) with a layered structure. Various characterizations confirmed that incorporating PVP and GN effectively suppressed particle agglomeration at high temperatures. The optimized GN-LNCO exhibited excellent physicochemical properties, including a specific surface area of 45.21 m 2 g −1 , a more regular mesoporous structure, a higher electronic conductivity, and a greater oxygen vacancy concentration. Electrochemical performance tests showed that the GN-LNCO cathode demonstrated an outstanding performance in solid oxide fuel cells at 800 °C, with a peak power density of 350.91 mW cm −2 . This represented an improvement of 28.65% over the conventional LNCO. Additionally, a 72 h long-term stability test of a GN-LNCO single cell revealed a voltage decay rate of only 1.60%, indicating its excellent stability. Overall, this study provides a novel material design strategy for developing high-performance cathodes, which has significant implications for advancing solid oxide fuel cell technologies.
Fibrous perovskite oxide has been the most promising cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs) due to its efficient mass and charge transfer. Herein, a core–shell fiber-structured YCo0.5Fe0.5O3 (YCF)–Gd0.1Ce0.9O1.95 (GDC) cathode is synthesized via the modified electrospinning technique. These unique YCF–GDC fibers exhibit a uniform diameter of 300 nm, and the GDC particles are attached to the YCF fiber cores. The electrochemical performance demonstrates a relatively low area-specific resistance of 0.66 Ω·cm2 at 550 °C in air, which is much lower than 1.56 Ω·cm2 of pure YCF fiber cathode. Moreover, the distribution of relaxation times (DRT) analysis results indicate that the introduction of GDC nanoparticles and the core–shell structure greatly facilitate oxygen-ion conduction and charge transfer processes, and the oxygen incorporation process plays a major role in the total polarization resistance. The NiO–GDC|GDC|fibrous YCF–GDC fuel cell shows a maximum power density of 426.5 mW·cm–2 at 550 °C. These results display that the core–shell fiber-structured YCF–GDC composite oxide is a promising candidate of highly active cathode for IT-SOFCs.
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