The spinel compounds are a class of intriguing electrode
materials
for redox-based supercapacitors owing to their high specific capacity
and variable redox sites, but they are constrained by cyclic instability
and an inadequate rate capability. The integration of suitable two-dimensional
(2D) electrode nanomaterials with spinel compounds not only facilitates
an effective charge transfer but also introduces more redox active
sites, presenting significant electrochemical performance. Herein,
a 0D/2D ZnNi2O4/WS2 (WZNO) hybrid
nanostructure has been developed where WS2 nanoflakes (WNFS)
act as a supportive matrix, allowing effective dispersion of ZnNi2O4 nanoparticles (ZNO) over its surface and thereby
exposing numerous electrochemically active sites. The developed flexible
electrode shows remarkable faradaic redox phenomena, exhibiting significant
specific capacitance (184.8 F/g), impressive cyclic stability (38.5
± 0.03%), and coulombic efficiency (94.7 ± 0.004%) up to
10,000 cycles. The ab initio calculations have demonstrated synergistic
coupling between the constituents of the metallic ZnNi2O4/WS2 hybrid nanostructure, via interfacial
charge transport, elucidating its significant electrochemical properties.
The asymmetric supercapacitor exhibits superior specific capacitance
(171.3 F/g), showcasing remarkable energy (61.6 W h/kg) and power
density (1236.5 W/kg). Conversely, the quasi-solid-state supercapacitor
demonstrates significant power (20.4 W h/kg) and energy density (921.2
W/kg) with impressive capacitance retention (97.2 ± 0.03%). The
fabricated devices can illuminate different-colored LEDs, along with
a fully operational clock and calculator, highlighting their significant
potential as electrode materials in storage applications.