The
sluggish charge transport kinetics that exist in the energy
storage process of all-solid-state supercapacitors (ASSSCs) can be
improved by designing open hierarchical porous structures for binder-free
electrodes. Herein, a template-directed strategy is developed to fabricate
open hierarchical porous Ni–Co–Zn–P nanoplate
arrays (NCZP6T) through phosphating the electrodeposited
NiCo–LDH nanosheets loaded on a template. At first, porous
conductive NiZn alloy nanoplate arrays are rationally devised as the
template by a strong magnetic field (SMF)-assisted electrodeposition.
The Lorentz force caused by coupling the SMF with the electrical current
induces a magnetohydrodynamic (MHD) flow (including the micro-MHD
flow), which homogenizes the deposition coating, tunes the nucleation
and growth of the NiZn alloy, and produces pores in the nanoplates.
The open hierarchical porous structure offers a larger specific surface
area and pore volume for accelerating charge transport and gives a
synergistic effect between the inner porous conductive NiZn array
template and the outer electrochemical active phosphides for high-performance
hybrid ASSSCs. Accordingly, the battery-type electrode of NCZP6T shows a much higher specific capacitance of 3.81 F cm–2 at 1 mA cm–2, enhanced rate capability,
and remarkable cycling stability at progressively varying current
densities. Finally, the NCZP6T//FeS ASSSC delivers a high
energy density of 77 μW h cm–2 at a large
power density of 12 mW cm–2, outperforming most
state-of-the-art supercapacitors.