Zn–Ni–Se@NiCo2S4 Core–Shell Architectures: A Highly Efficient Positive Electrode for Hybrid Supercapacitors

To meet the demand for the prominent electrode materials having a battery-like nature for hybrid supercapacitors, the suitable designs of promising core–shell structures are greatly needed. Herein, hierarchical Zn–Ni–Se@NiCo 2 S 4 nanoarchitectures on the surface of nickel foam (ZNSe@NCS@NF) as a highly efficient cathode electrode are successfully prepared using a hydrothermal and selenization technique for NiZnSe nanowires and an electrodeposition strategy for NiCo 2 S 4 nanosheets. Field emission scanning electron microscopy images demonstrate that the core one-dimensional ZNSe and shell two-dimensional NCS are interconnected to form a three-dimensional hierarchical and porous ZNSe@NCS nanoarchitecture, leading to the efficient and fast transfer/transmission of both electrons and electrolyte ions. In a three-electrode cell, the ZNSe@NCS@NF electrode acquires excellent capacity (393.7 mAh g –1 /1417.3 C g –1 at 1 A g –1 ), considerable rate performance (maintaining 79.25% at 24 A g –1 ), and an amazing durability (maintaining 95.5% after 10 000 cycles at 24 A g –1 ), which are superior to the ZNSe@NF electrode. Besides, the sandwiched hybrid device using ZNSe@NCS@NF as an attractive cathode electrode and activated carbon@nickel foam (AC@NF) as an anode electrode represents the notable capacity of 65.42 mAh g –1, desirable rate performance of 69.15% at 24 A g –1, desirable life span (93.3% capacity retention after 10 000 cycles at 18 A g –1 ), and promising energy density of 52.37 Wh kg –1 at 800.5 W kg –1 . The present synthesis protocol offers a meritorious reference for the fabrication of other kinds of metal selenide/sulfide electrode materials with core–shell structures for various applications.