Interlaced Ni-Co LDH nanosheets wrapped Co9S8 nanotube with hierarchical structure toward high performance supercapacitors

Abstract

High electrochemical performance of supercapacitor electrodes largely rely on the smart design of nanoarchitectures with scrupulous combination of different active materials. We present a facile method for the multicomponent design of hierarchical Co9S8 hollow nanotubes (CS NTs) wrapped with Ni-Co layered double hydroxides nanosheets (Ni-Co LDH NSs) core-shell high-performance supercapacitors. The CS NTs serve as an ideal backbone with pentagonal cross-section to enhance the conductivity for acting as a “superhighway” for electron transport, whereas the Ni-Co LDH NSs with high electrochemical activity electrodeposited on the surface of CS NTs provide the electroactive sites and enhance the structural stability for faradaic reaction. The CS NTs@Ni-Co LDH NSs hierarchical electrode presents a high specific capacitance of 1020 C g−1 and high cycling stability of 90.4% after 10,000 cycles. Moreover, an asymmetric supercapacitor (ASC) was assembled with CS NTs@Ni-Co LDH NSs as the anode and active carbon as cathode. The as-fabricated ASC shows high energy density of 50 Wh kg−1 and exhibit superior cyclic stability of 86.4% retention over 5000 cycles, suggesting this electrode is promising for efficient electrochemical capacitors.