Designed Assembly of Porous Cobalt Oxide/Carbon Nanotentacles on Electrospun Hollow Carbon Nanofibers Network for Supercapacitor

Abstract

Porous and hollow nanomaterials have been an exciting research area for numerous next-generation technological applications. However, it is still a challenge to assemble porous and hollow nanostructures of appropriate composition and characteristics in designed architectures. Here, we report a self-templated metal− organic frameworks based strategy for the synthesis and engineering of porous and hollow nanostructures in designed architectures by developing graphitic-carbonintermingled porous Co 3 O 4 nanotentacles, for the first time, on electrospun hollow carbon nanofibers in a designed 3D pattern (3D Co 3 O 4 /C@HCNFs). The asdeveloped nanocomposite sheet, as a free-standing electrode for supercapacitors, shows a high specific capacity of 199 mA h g −1 (1623 F g −1 ) at 1 A g −1 with good cyclic life and outstanding rate capability. Moreover, the assembled asymmetric supercapacitor device supplies an energy density of 36.6 W h kg −1 at the power density of 471 W kg −1 with significant cyclic life and rate capability indicating its potential practical application. This synthetic strategy suggests a simple, cost-effective and convenient route for the synthesis and assembly of porous and hollow structured nanomaterials in designed architectures for diverse applications.

Structural design toward functional materials by electrospinning: A review

“…The third method is to use coaxial electrospinning to prepare electrospun fiber precursor with core-shell structure and then the precursor electrospun fibers were calcined at high temperature, which can also result in the hollow structure fiber (131). Dai et al (132) reported a onepot direct electrospinning, using coaxial electrospinning to prepare hollow nanofibers.…”

“…Another interesting work for the functional hollow electrospun composite fibers was reported by Mukhiya et al (131). They used coaxial electrospinning and hydrothermal methods to prepare hollow Co 3 O 4 with threedimensional (3D) structure ( Figure 10).…”

A Review of Electrospun Carbon Nanofiber-Based Negative Electrode Materials for Supercapacitors

“…(i) CNFs are very economical compared to graphene and carbon nanotubes and can be easily fabricated on a mass scale. (ii) With proper modifications of the electrospinning technique, precursor composition, or position, followed by a postmodification, carbon nanofibers with extraordinary porosity, a high specific surface area, and diverse functionalities can be fabricated [83][84][85][86][87][88]. (iii) CNFs can be directly used as a free-standing electrode without the use of a conductive additive, binder, or current collector.…”

The Application of Metal–Organic Frameworks and Their Derivatives for Supercapacitors

“…The sulfur-doped ZIF-67 derived Co 3 O 4 on NF (S-Co 3 O 4 /NF), prepared via the hydrothermal, annealing and sulfurization methods ( Figure 5 b), delivered superior specific capacity of 178 mAh g −1 (1424 F g −1 ) at 1 A g −1 and good cycling stability (81.5% capacitance retention after 8000 cycles at 3 A g −1 ). Mukhiya et al [ 94 ] synthesized binder-free 3D porous Co 3 O 4 /C@HCNFs (HCNFs = hollow carbon nanofibers) by the preparation of graphitic-carbon-intermingled porous Co 3 O 4 nanotentacles, which exhibit an excellent specific capacity of 1623 F g −1 at 1 A g −1 and long cyclic life, as well as good rate capability ( Figure 5 c). Bao et al [ 95 ] utilized ZIF-67 as the template and NaH 2 PO 2 as the etching agent to construct a series of Co 3 O 4 embedded α-Co/Ni(OH) 2 hollow nanocages ( Figure 5 d).…”

“… Schematic illustration for the preparation and electrochemical properties of ( a ) hollow Co 3 O 4 arrays on carbon cloth: Step I, electrochemical deposition; Step II, in situ growth; and Step III, two steps annealing [ 92 ]. ( b ) S-Co 3 O 4 electrode [ 93 ], ( c ) 3D Co 3 O 4 /C@HCNFs nanocomposite [ 94 ] and ( d ) α-CoNi(OH) 2 @Co 3 O 4 -70 nanocage [ 95 ]. ( a , b , d ) Elsevier, 2020.…”