Reasonable design of materials with complex nanostructures
and
diverse chemical compositions is of great significance in the field
of energy storage. Cu7KS4 (CKS) is considered
a potential electrode material for supercapacitors due to its superior
electrical conductivity. Transition metal hydroxides are widely used
as electrode materials for supercapacitors due to their high theoretical
specific capacitance (C
s); however, single
metal species with limited active sites restrict their further applications
for energy storage. Herein, through a hydrothermal reaction, CKS nanorods
were prepared, and then binary metal hydroxide Ni
x
Co1–x
(OH)2 nanosheets
were generated directly on CKS nanorods through a one-step hydrothermal
reaction to form a nano-core–shell structure (NCSS). By regulating
the mole ratio of nickel nitrate to cobalt nitrate, the resulting
Ni0.75Co0.25(OH)2 nanosheets with
the best electrochemical activity were prepared and supported on CKS
nanorods to form a CKS@N0.75C0.25OH NCSS. The
as-prepared CKS@N0.75C0.25OH NCSS has a larger
specific surface area, which can provide more active sites, while
the abundant metal species composition can generate abundant redox
reactions to boost the pseudocapacitance. The prepared CKS@N0.75C0.25OH/NF electrode exhibits outstanding specific capacitance
and cycle life. The assembled CKS@N0.75C0.25OH/NF//AC all-solid-state asymmetric supercapacitor achieves a high
energy density of 88.7 Wh kg–1 at a power density
of 849.9 W kg–1 with superior cycle life. Therefore,
the use of polymetallic hydroxides to construct NCSS electrodes has
great research significance and broad application prospects.