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摘要
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Background
Although high theoretical capacitance, low cost, and superior cycling reversibility make NiO a promising material for preparing supercapacitors, poor conductivity and ionic transport have limited its applicability.
Methods
To overcome these drawbacks, in this study we prepared ternary composites from porous NiO nanosheets, polyaniline:poly(sodium 4-styrenesulfonate) (PANI:PSS), and Ni/NiO-decorated multiwalled carbon nanotubes (MWCNTs). Using a spray-drying technique, the conductive PANI:PSS was bound tightly to the porous NiO nanosheets to form PANI:PSS/NiO (P-NiO) microspheres. Here, the PANI:PSS infiltrated the nanopores of NiO and modified the NiO surface, thereby decreasing the internal resistance and avoiding restacking of the NiO nanosheets. Moreover, we synthesized MWCNTs decorated with Ni/NiO dual-phase nanoparticles; here, the deposition of the Ni/NiO nanoparticles improved both the electrical conductivity and capacitive behavior of the MWCNTs.
Significant findings
As a result, the modified MWCNTs (m-MWCNTs) functioned as a novel additive that lowered the external resistance among the P-NiO microspheres. An asymmetric supercapacitor employing the designed ternary system and active carbon as electrodes achieved a remarkable specific capacitance of 105.6 F/g at 0.5 A/g, a maximum energy density of 33 W h/kg, and superior cycling stability. |