Exploring the storage applications of FeS–ZnO nanocomposite as a negative electrode for asymmetric supercapacitors

Abstract

This paper reports a low-cost and facile wet-chemical method to fabricate FeS–ZnO nanocomposites, offering promising potential for next-generation supercapacitor applications. The FeS–ZnO electrode exhibits rapid faradaic redox reactions and sufficient electrochemical double-layer charge storage in an aqueous medium, achieving a high specific capacitance of 485.10 F g⁻¹ within a potential range of −0.8 to 0.0 V. The FeS–ZnO composite outperforms its components, FeS and ZnO, by exhibiting enhanced electrochemical properties. An asymmetric supercapacitor utilizing a FeS–ZnO‖MnO₂ configuration in KOH electrolyte demonstrates exceptional rate capability, delivering a capacitance of 145.62 F g⁻¹, an extended voltage window of 1.6 V, and reliable performance over 10 000 cycles. The FeS–ZnO nanocomposite shows great promise as an efficient electrode material for next-generation energy storage, delivering a high energy density of 51.77 Wh kg⁻¹ along with a power density of 4000 W kg⁻¹.