Microwave-assisted synthesis of hybrid supercapacitors consisting of Ni, Co-layered double hydroxide shell assembled around wood-derived activated carbon fiber core

Activated carbon fibers (ACFs) are prepared from the discarded fir wood using two-step melt-spinning and CO2 activation post-treatment. Then, composites composed of these ACFs and Ni, Co-layered double hydroxides (NiCo-LDH@ACF) are synthesized by a microwave-assistant hydrothermal strategy. NiCo-LDHs agglomerated around ACFs, forming core-shell structures with sheet-or microsphere-like morphologies, which provide large surface area, hierarchical porosity, and numerous active sites for efficient charge and mass transfer. The NiCoLDH@ACFs are used as an active material to construct the supercapacitors, the highest of capacitance and the corresponding rate performance of which are equal to 1453.3 F/g at 1 A/g and 78% at 10 A/g by microwave assistant hydrothermal at 120 ?, respectively. We also use this material to assemble an asymmetric super capacitor using activated carbon derived from fir bark as a negative electrode. The resulting device demonstrates excellent capacitance (equal to 146.9 F/g at 1.6 V), very high energy density (equal to 52.2 Wh/kg at 800 W/kg), and cycle life (judging by the 79.8% capacitance retention after 10000 cycles).

Automated summary

In this study, activated carbon fibers (ACFs) were prepared from discarded fir wood and composites composed of these ACFs and Ni, Co-layered double hydroxides (NiCo-LDH@ACF) were synthesized using a microwave-assistant hydrothermal strategy. The resulting core-shell structures with sheet-or microsphere-like morphologies provide a large surface area and numerous active sites for efficient charge and mass transfer. The NiCoLDH@ACFs were used to construct high-performance supercapacitors, and an asymmetric supercapacitor was also assembled using activated carbon derived from fir bark. The resulting devices exhibited excellent capacitance, energy density, and cycle life.