The practical implementation of supercapacitors is hindered by low utilization and poor structural stability of electrode materials. Herein, to surmount these critical challenges, a three-dimensional hierarchical α-Co(OH)
2
/α-Ni(OH)
2
heterojunction nanorods are built
in situ
on Ni foam through a mild two-step growth reaction. The unique lamellar crystal structure and abundant intercalated anions of α-M(OH)
2
(M = Co or Ni) and the ideal electronic conductivity of α-Co(OH)
2
construct numerous cross-linked ion and electron transport paths in heterojunction nanorods. The deformation stresses exerted by α-Co(OH)
2
and α-Ni(OH)
2
on each other guarantee the excellent structural stability of this heterojunction nanorods. Using nickel foam with a three-dimensional network conductive framework as the template ensures the rapidly transfer of electrons between this heterojunction nanorods and current collector. Three-dimensional hierarchical structure of α-Co(OH)
2
/α-Ni(OH)
2
heterojunction nanorods provides a large liquid interface area. These result together in the high utilization rate and excellent structure stability of the α-Co(OH)
2
/α-Ni(OH)
2
heterojunction nanorods. And the capacitance retention rate is up to 93.4% at 1 A g
−1
from three-electrode system to two-electrode system. The α-Co(OH)
2
/α-Ni(OH)
2
//AC device also present a long cycle life (the capacitance retention rate is 123.6% at 5 A g
−1
for 10000 cycles), a high specific capacitance (207.2 F g
−1
at 1 A g
−1
), and high energy density and power density (72.6 Wh kg
−1
at 196.4 W kg
−1
and 40.9 Wh kg
−1
at 3491.8 W kg
−1
), exhibiting a fascinating potential for supercapacitor in large-scale applications.
Fiber-shaped supercapacitors have drawn much attention for their great potential application in future portable and wearable electronics because of their outstanding flexibility, tiny volume, and good deformability. In this work, commercial poly(ethylene terephthalate) (PET) thread was successfully converted into an electrically conductive and electrochemically active thread by introducing copper sulfide (CuS) and polyaniline (PANI) via simple chemical bath deposition and electrochemical deposition. The obtained PANI/CuS/PET electrode combined all the advantages of PET, CuS, and PANI, showing an excellent physical and electrochemical performance. The fiber-shaped supercapacitor exhibits a high specific capacitance of 29 mF cm −2 (116 mF cm −2 for a single electrode) and good cycling stability with 93.1% retention after 1000 cycles. With the simple preparation method and low-cost raw materials, this strategy provides a reference for the fabrication of portable/wearable energy storage devices.
Layered double hydroxides (LDHs) were synthesized by a coprecipitation method. The synergistic flame retardant effect of nano-silicon dioxide (nano-SiO2) on ethylene vinyl acetate (EVA)/LDHs composites was studied using limiting oxygen index (LOI), cone calorimeter test (CCT), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Results showed that the LOI values of the EVA/LDHs/nano-SiO2 composites were basically higher than that of the EVA/LDHs composite, and the EVA composite with 48% LDHs and 2% nano-SiO2 reached an LOI value of up to 31.2%. The CCT results indicate that the addition of nano-SiO2 greatly reduced the heat release rate, total heat release, mass loss, smoke production rate, total smoke release, and smoke factor. The morphology and structures of residues investigated by SEM gave positive evidence that char layers formed from the EVA/LDHs/nano-SiO2 composites were improved. The TGA data showed that the EVA/LDHs/nano-SiO2 composites show a higher thermal stability than the EVA/LDHs composites.
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