Synthesis of Fe₃O₄/FeS₂ composites via MOF-templated sulfurization for high-performance hybrid supercapacitors

The development of advanced anode materials for supercapacitors is crucial for driving innovation in the field of new energy technologies. Although iron-based materials show promise, their electrical conductivity and cyclic stability remain challenges. In this study, Fe₃O₄/FeS₂ composites were synthesized using a sacrificial MOF template and a solid-state sulfurization process. The composite retained the morphology of Fe-MOF, with numerous nanoscale particles formed through heterogeneous sulfurization. The SMFO-2 composite exhibited a specific capacity of 208.5 mAh g^-1 at a current density of 1 A g⁻¹. In a hybrid supercapacitor (HSC) constructed with SMFO-2 as the anode and super-electric activated carbon (AC) as the cathode, the device demonstrated a capacity retention rate of 78.6% after 10,000 cycles at 2 A g⁻¹. Furthermore, the HSC achieved an optimal energy density of 28.8 Wh kg⁻¹ with a power density of 375 W kg⁻¹, successfully powering a small bulb, highlighting its strong potential for practical applications.