Hierarchical FeCoSe2@NiCo-layered double hydroxide nanosheet arrays with boosted performance for hybrid supercapacitors

Abstract

For constructing high-performance hybrid supercapacitor devices, it is vital to exploit a battery-type cathode with enhanced kinetics and improved cyclic performance to match with a capacitive anode. Herein, highly porous FeCoSe2@NiCo-LDH core-shell nanosheet arrays were in situ decorated on face of carbon cloth via an electrodeposition approach and a selenylation treatment. The hierarchical heterostructure consisting of two types of vertically aligned interconnected two-dimensional nanosheets not only offers huge surface area and available diffusion pathways for quick electron/ion transport, but also generates plentiful heterointerfaces with modified electronic structure and enables synergetic effect between dual components. Consequently, the well-designed FeCoSe2@NiCo-LDH electrode displays a greatly boosted specific capacity of 220.9 mA h g−1 at 1 A g−1, 83.5% capacity retention at 20 A g−1, and wonderful cyclic stability, which are superior to those of single component. Furthermore, the hybrid supercapacitor device with a FeCoSe2@NiCo-LDH electrode and a hierarchical porous carbon electrode illustrates an extensive energy density of 65.9 Wh kg−1 at 1.248 kW kg−1 combined with long lifetime with 87.6% capacity retention over 10,000 cycles. These superb properties manifest that the integrated FeCoSe2@NiCo-LDH electrode owns a desirable application prospect in hybrid energy storage systems.