skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Cobalt Oxide-Decorated Silicon Carbide Nano-Tree Array Electrode for Micro-Supercapacitor Application
A cobalt oxide (Co3O4)-decorated silicon carbide (SiC) nano-tree array (denoted as Co3O4/SiC NTA) electrode is synthesized, and it is investigated for use in micro-supercapacitor applications. Firstly, the well-standing SiC nanowires (NWs) are prepared by nickel (Ni)-catalyzed chemical vapor deposition (CVD) method, and then the thin layer of Co3O4 and the hierarchical Co3O4 nano-flower-clusters are, respectively, fabricated on the side-walls and the top side of the SiC NWs via electrodeposition. The deposition of Co3O4 on the SiC NWs benefits the charge transfer at the electrode/aqueous electrolyte interface due to its extremely hydrophilic surface characteristic after Co3O4 decoration. Furthermore, the Co3O4/SiC NTA electrode provides a directional charge transport route along the length of SiC nanowires owing to their well-standing architecture. By using the Co3O4/SiC NTA electrode for micro-supercapacitor application, the areal capacitance obtained from cyclic voltammetry measurement reaches 845 mF cm−2 at a 10 mV s−1 scan rate. Finally, the capacitance durability is also evaluated by the cycling test of cyclic voltammetry at a high scan rate of 150 mV s−1 for 2000 cycles, exhibiting excellent stability.  more » « less
Award ID(s):
1903188
PAR ID:
10326353
Author(s) / Creator(s):
; ; ; ; ;
Date Published:
Journal Name:
Materials
Volume:
14
Issue:
16
ISSN:
1996-1944
Page Range / eLocation ID:
4514
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; (, ACS Applied Polymer Materials)
    Supercapacitor energy storage devices are well suited to meet the rigorous demands of future portable consumer electronics (PCEs) due to their high energy and power densities (i.e., longer battery-life and rapid charging, respectively) and superior operational lifetimes (10 times greater than lithium-ion batteries). To date, research efforts have been narrowly focused on improving the specific capacitance of these materials; however, emerging technologies are increasingly demanding competitive performance with regards to other criteria, including scalability of fabrication and electrochemical stability. In this regard, we developed a polyaniline (PANI) derivative that contains a carbazole unit copolymerized with 2,5-dimethyl-p-phenylenediamine (Cbz-PANI-1) and determined its optoelectronic properties, electrical conductivity, processability, and electrochemical stability. Importantly, the polymer exhibits good solubility in various solvents, which enables the use of scalable spray-coating and drop-casting methods to fabricate electrodes. Cbz-PANI-1 was used to fabricate electrodes for supercapacitor devices that exhibits a maximum areal capacitance of 64.8 mF cm–2 and specific capacitance of 319 F g–1 at a current density of 0.2 mA cm–2. Moreover, the electrode demonstrates excellent cyclic stability (≈ 83% of capacitance retention) over 1000 CV cycles. Additionally, we demonstrate the charge storage performance of Cbz-PANI-1 in a symmetrical supercapacitor device, which also exhibits excellent cyclic stability (≈ 91% of capacitance retention) over 1000 charge–discharge cycles. 
    more » « less
  2. ; ; ; ; ; ; ; ; (, Chemistry – A European Journal)
    Abstract In this work, an organic‐inorganic hybrid crystal, violet‐crystal (VC), was used to etch the nickel foam (NF) to fabricate a self‐standing electrode for the water oxidation reaction. The efficacy of VC‐assisted etching manifests the promising electrochemical performance towards the oxygen evolution reaction (OER), requiring only ~356 and ~376 mV overpotentials to reach 50 and 100 mA cm−2, respectively. The OER activity improvement is attributed to the collectively exhaustive effects arising from the incorporation of various elements in the NF, and the enhancement of active site density. Furthermore, the self‐standing electrode is robust, exhibiting a stable OER activity after 4,000 cyclic voltammetry cycles, and ~50 h. The anodic transfer coefficients (αa) show that the first electron transfer step is the rate‐determining step on the surface of NF‐VCs‐1.0 (NF etched by 1 g of VCs) electrode, while the chemical step involving dissociation following the first electron transfer step is identified as the rate‐limiting step in other electrodes. The lowest Tafel slope value observed in the NF‐VCs‐1.0 electrode indicates the high surface coverage of oxygen intermediates and more favorable OER reaction kinetics, as confirmed by high interfacial chemical capacitance and low charge transport/interfacial resistance. This work demonstrates the importance of VCs‐assisted etching of NF to activate the OER, and the ability to predict reaction kinetics and rate‐limiting step based onαavalues, which will open new avenues to identify advanced electrocatalysts for the water oxidation reaction. 
    more » « less
  3. ; ; (, CrystEngComm)
    Germanium nanowires (NWs) have attractive properties for a variety of applications, including micro- and optoelectronics, memory devices, solar energy conversion, and energy storage, among others. For applications that involve exposure to air, the poor chemical stability and electronic surface passivation of native oxides have remained a long-standing concern. Termination by sulfur-rich surface layers has emerged as a promising strategy for passivation of planar Ge surfaces. Here we discuss experiments on solid-state sulfurization of Ge nanowires in sulfur vapor at near-ambient pressures and at different temperatures. Combined transmission electron microscopy imaging and chemical mapping establishes that Ge NWs remain intact during vapor-phase reaction with S at elevated temperatures, and show the formation of sulfur-rich shells with T-dependent morphology and thickness on the Ge NW surface. Photoluminescence of ensembles of such core–shell nanowires is dominated by strong emission at ∼1.85 eV, consistent with luminescence of GeS. Cathodoluminescence spectroscopy on individual NWs establishes that this luminescence originates in thin GeS shells formed by sulfurization of the NWs. Our work establishes direct sulfurization as a viable approach for forming stable, wide-bandgap surface terminations on Ge NWs. 
    more » « less
  4. ; ; ; ; (, Journal of energy storage)
    In this study, we synthesized carbyne by a simple chemical route and then this was coated on nickel foam. On this carbyne coated nickel foam, FeCo2O4 was grown by the solvothermal process to serve as a nanohybrid electrode for supercapacitor applications. This nanohybrid electrode has shown high specific capacitance due to the large surface area, high electrical conductivity and improved rate characteristics. The specific capacitance of FeCo2O4 @ Carbyne nanohybrid electrode was about 2584.8 Fg-1 at the current density of 3 Ag-1. Furthermore, the asymmetric supercapacitor device integrated with FeCo2O4 @ Carbyne and activated carbon (FeCo2O4 @ Carbyne || AC) shows better performance with an energy density of about 96.59 WhKg-1 at a high-power density of 2.25 kW kg-1 with a capacitance decay of about 14.52 % even at 5000 cycles. These outcomes provide a new approach for the development of supercapacitors with superior characteristics. 
    more » « less
  5. ; ; ; ; ; ; ; (, Journal of Materials Chemistry A)
    Synthesis of nitrogen doped mesoporous graphitic carbon spheres with dispersed metal oxide nanoparticles using a single temperature treatment step serves as one of the big challenges in materials research. To date only a few reports have been published on the soft-templating synthesis of mesoporous graphitic carbons. The preparation of graphitic carbons with dispersed Fe 2 O 3 using a single carbonization step at relatively low temperatures is yet to be explored. The first phase of this work shows the potential of graphitization of polyvinylpyrrolidine (PVP) stabilized cubic Prussian blue nanoparticles (CPB) in phenolic resin spheres to produce graphitic carbon spheres through a facile Stöber-like method. In the second phase, the Pluronic F127 soft template was used along with PVP stabilized Prussian blue nanoparticles (PB) in carbon spheres to generate mesopores and graphitic domains with uniformly dispersed Fe 2 O 3 nanoparticles in these spheres. Due to the presence of graphitic layers, doped N species and Fe 2 O 3 nanoparticles in the carbon matrix, the yielded carbon spheres feature a high surface area and magnetic properties. Moreover, these graphitic spheres exhibited excellent capacitive behavior with rectangular cyclic voltammetry (CV) profiles and large capacitance up to 247 F g −1 at 1 mV s −1 scan rate in 6 M KOH solution. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email