Ni3S2@NiCo-LDH cross-linked nanosheet arrays on Ni foam for high-performance all-solid-state asymmetric supercapacitors

Abstract

Nickel-Cobalt layered double hydroxide (NiCo-LDH) nanosheets have the advantages of large interlayer spacing, adjustable structure, and high theoretical capacity, which has attracted extensive attention. However, the poor conductivity and structural instability limit their application in electrode materials. Herein, a high-performance all-solid-state asymmetric supercapacitor (ASC) is designed with AC as the anode and Ni3S2@NiCo-LDH as the cathode. The open Ni3S2@NiCo-LDH cross-linked nanosheets arrays are uniformly arranged on the Ni foam (NF), which not only increases the sufficient contact area between electrode and electrolyte, but also facilitates the rapid transfer of electrons. Therefore, the assembled ASC exhibits high area-specific capacitance of 1267.2 mF cm−2 at 5 mA cm−2, high energy density of 450.60 μW h cm−2 at the power density of 3.99 mW cm−2, and excellent cyclic stability with 85.2 % capacity retention over 5000 cycles. This work demonstrates the feasibility of the cross-linked nanosheets arrays of Ni3S2@NiCo-LDH on NF, which shows great potential as electrode for novel energy storage devices.