3D hierarchical NiCo2O4@Co3S4@MnS@PPy core-sheath nanowire arrays as high-performance electrode for all-solid-state asymmetric supercapacitors

To cater to the mushrooming advanced energy storage devices need, designing and preparing novel electrode materials with excellent electrochemical properties (including high capacitance and prominent cycling stability) are urgent but challenging. Here, we successfully synthesized 3D hierarchical NiCo2O4@Co3S4@MnS@PPy (NC@CS@MS@PPy) core-sheath nanowire arrays grown on highly conductive carbon cloth using a multistage process. Owing to a lot of synergy between the multiple components in the as-obtained composite, the prepared electrode material indicates an excellent specific capacitance of 2.67 F cm−2 at 1 mA cm−2 or 2557.58 F g−1 at 1 A g−1 and high cycling stability (83.64 % capacitance retention after 20,000 cycles even at a high current density of 20 mA cm−2). When coupled with the activated carbon (AC, as a negative electrode), the assembled all-solid-state NC@CS@MS@PPy//AC asymmetric supercapacitor (ASC) device showed outstanding electrochemical properties with a high area specific capacitance 684.38 mF cm−2 at 3 mA cm−2 and better long-term cycling stability (96.76 % retention of the initial capacitance after 20,000 cycles). More importantly, by taking advantaging of the multiple compositional merits and structural features of the positive electrode, the device delivered the highest energy density of 81.1 Wh kg−1 at 800 W kg−1 and retained 26.2 Wh kg−1 at the highest power density of 16 KW kg−1. Furthermore, two ASCs connected in series powered 20 red light-emitting diodes (LEDs) for >10 min. This work manifests that the prepared hierarchical NC@CS@MS@PPy core-sheath nanowire arrays have impressive potential as high-performance electrodes for supercapacitor.