Template-Induced
Ni(OH)2 Nanosheet-Constructed
Hierarchically Porous Aerogel Boosts Superior Specific Capacitance
and Rate Performance for Supercapacitors
Hierarchically porous materials are promising electrode
materials
for supercapacitors due to their high surface area and large amounts
of interconnected active sites. As a three-dimensional (3D) porous
material, aerogels can further increase the exposure of active sites
and improve the ion transport by constructing hierarchically porous
structures. Herein, a kind of 3D hierarchically porous Ni(OH)2 aerogel (HP-NiA) constructed by a template-directed Ni(OH)2 nanosheet can be obtained via combining the sol–gel
method and template-etching method, in which the controllable pore
size was achieved via using the mesoporous silica-KIT-6 and silicon
template KH570 as sacrificial templates. The microporous cavities
are interconnected with mesopores and macropores, which enable full
contact of active sites with electrolytes and facilitate quick transport
of ions. Benefiting from the hierarchically porous structure and the
high active specific surface area (1577.5 cm2), the amorphous
HP-NiAs exhibit ultrahigh specific capacitance (5578 F/g at 1 A/g),
excellent rate performance (3698 F/g at 20 A/g), and superior cycling
stability (72.5% capacitance retention after 10,000 cycles), which
are superior to the state-of-the-art supercapacitor electrode materials.
This work highlights the importance of the rational design on the
hierarchical structure and provides a feasible strategy to construct
hierarchical porous materials for energy-storage applications.