Core–shell metal sulfide composite materials and PEDOT:PSS decorated with MnO2 on nickel foam for high-performance super-capacitor applications

Abstract

Great attention has been paid to the design and synthesis of distinct core/shell hetero-structures for high-performance supercapacitors. We prepared unique hetero-structures on a nickel foam through a facile and cost-effective chemical bath deposition method and hydrothermal method combined with a dip-coating process and drop casting. Metal sulfides have attracted substantial attention owing to their outstanding properties and are used in multiple application areas, such as electrochemical energy conversion and energy storage. Herein, we describe a cost-effective and facile solution approach for the preparation of two different metal sulfides (NiS and CuS) grown on ZnO NRs as a good electrical conductor, facilitating the growth of polymer. The synthesized ZnO NRs@NiS/CuS@PEDOT:PSS@MnO₂ core–shell supercapacitor electrode materials were then thoroughly characterized. A CuS nanoparticle-supported electrode (ZnO NRs@CuS@PEDOT:PSS@MnO₂) was constructed and exhibited a high capacitance of 2554.61 F g⁻¹ at 0.71 A g⁻¹, which is higher than that of ZnO NRs@NiS@PEDOT:PSS@MnO₂ electrodes (2072.52 F g⁻¹ at 0.71 A g⁻¹). After 3000 cycles at a high current density of 1.2 A g⁻¹, the retention rate was 98%, indicating good long-term cycling stability. These results indicate that the ZnO NRs@CuS@PEDOT:PSS@MnO₂ electrode is promising for high-performance supercapacitor applications.