(401d) Advanced Asymmetric Supercapacitor Based on Nanoporous Carbon and Fe3O4 from a Single Metal-Organic Frameworks (MIL-100(Fe))

Asymmetric supercapacitors (ASCs) have garnered considerable global interest due to their broader voltage window in comparison to symmetric supercapacitors (SCs). By integrating two electrodes that possess distinct charge storage methodologies or dissimilar redox reactions, an expanded operating voltage window may be achieved for ASCs. In this study, the influence of synthesis conditions was investigated by successfully synthesizing MIL-100 (Fe) using three different iron salts (iron powder, nitrate, and chloride). Subsequently, two carbon materials with different pore structures Fe₃O₄ metal oxide were obtained from a single MOF and the electrochemical performance was evaluated in a 6M KOH electrolyte. The carbon material derived from MIL-100 (Fe) synthesized with Fe(III) nitrate exhibited a specific capacitance of 241 F/g at 0.1 Ag. On the other hand, the Fe₃O₄ metal oxide derived from MIL-100 (Fe) synthesized with Iron powder had the highest specific capacitance of 383.2 F/g at 0.1 A/g. For high ACSs performance, the porous carbons and Fe₃O₄ metal oxide demonstrating superior performance were assembled as anode and cathode materials for ASCs, respectively. Additionally, the assembled ACSs demonstrated a capacity retention rate of over 80% in a 5000-cycle charge-discharge test at 5 A/g. This strategy exhibited similar specific capacitance or even higher values when compared to conventional carbon-based materials.