Microwave synthesis of FeNiSb medium-entropy alloy as a high-performance electrode for symmetric supercapacitors

Supercapacitors, due to their unique energy storage mechanism, hold promise for alleviating the energy crisis. Electrode materials play a crucial role in supercapacitors, determining their overall performance. In this study, FeNiSb medium-entropy alloy (MEA) nanoparticles were successfully synthesized on nickel foam (NF) via a one-step microwave method. Benefiting from its unique surface morphology and the characteristic high configurational entropy and elemental synergistic effects of MEA, which collectively lead to superior ion-transport kinetics and abundant active sites, the material exhibited exceptional electrochemical performance. The FeNiSb electrode demonstrated a high specific capacitance of 1487.2 F g ^− 1 at 1 A g ^− 1 . Furthermore, a fabricated FeNiSb//FeNiSb symmetric supercapacitor (SSC) achieved an impressive energy density of 97.5 Wh kg ^− 1 at 750.2 W kg ^− 1 and superior cycling stability (80% retention after 5000 cycles). This study successfully employed FeNiSb MEA for SSC, demonstrating outstanding electrochemical performance and providing a viable solution for designing advanced energy storage materials.