Overcoming the sluggish activity of cathode materials is critical to realizing the wide‐spread application of intermediate‐temperature solid oxide fuel cells. Herein, a new way is reported to tune the performance of perovskite‐type materials as oxygen reduction electrodes by embedding anions (F − ) in oxygen sites. The obtained perovskite oxyfluorides SrFeO 3− σ − δ F σ and SrFe 0.9 Ti 0.1 O 3− σ − δ F σ (σ = 0.05 and 0.10) show improved electrocatalytic activity compared to their parent oxides, achieving area specific resistance values of 0.875, 0.393, and 0.491 Ω cm 2 for SrFeO 3− δ , SrFeO 2.95− δ F 0.05 , and SrFeO 2.90− δ F 0.10 , respectively, at 600 °C in air. Such improved performance is a result of the improved bulk diffusion and surface exchange properties due to anion doping. Moreover, favorable stability in performance is also demonstrated for the F − anion‐doped perovskites as oxygen reduction electrodes at 650 °C for a test period of ≈200 h. A combination of anion doping and cation doping may provide a highly attractive strategy for the future development of cathode materials.
Developing supercapacitors with simultaneous superior power and energy density for energy-storage devices remains a challenge. In this work, single-phase NiS2 microflowers were synthesized through a hydrothermal process coupled with subsequent sulfidation. The obtained NiS2 microflowers perfectly inherited the flowerlike structure of the precursor, which was composed of nanosheets with firmly integrated nanoparticles. With the benefit of the single-phase crystal structure, suppressed surface oxidation, relatively high apparent conductivity, and unique nano/microstructure, the NiS2 microflowers presented outstanding electrochemical performance in the LiOH electrolyte. Specifically, the NiS2 microflowers exhibited high specific capacities of 813 C g–1 at 1 A g–1 and 580 C g–1 at 20 A g–1 and retained 93% of its initial capacity after 10,000-time cycling test. Moreover, an optimized NiS2//activated carbon (AC) hybrid supercapacitor fabricated with NiS2 microflowers as the positive electrode and AC as the negative electrode operated stably at a large voltage window of 1.8 V. It further delivered a considerable energy density of 39.8 W h kg–1 at 900 W kg–1. Impressively, the intriguing nano/microstructure further endowed the almost unabated capacitance after continuous cycling of 10,000 times. This study will definitely promote the design and preparation of high-performance nickel-based sulfides for hybrid supercapacitors.
Developing a strategy for the resource utilization of spent zeolite catalysts is essential for addressing the environmental hazards of spent catalysts.
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