Pseudocapacitance Properties of Co3O4 Nanoparticles Synthesized Using a Modified Sol-Gel Method (original) (raw)
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Sol–Gel synthesis of Co3O4 nanoparticles as an electrode material for supercapacitor applications
Journal of Sol-Gel Science and Technology, 2020
Cobalt Oxide (Co3O4) nanoparticles were synthesized with an aid of urea by sol–gel method. The results of X-ray diffraction revealed that the formation of face-centered cubic (Fd3m) structure and the average crystallite size of the product were found to be 13.76 nm. The formation of cobalt oxide is confirmed by FT-IR analysis. The results of HR-TEM images reveal that Co3O4 nanoparticles were found to have within the range of 13–15 nm. At 3 M KOH, electrochemical analyses were investigated with impedance spectroscopy and an intrinsic pseudo capacitance and the results were reported. The results of Galvanostatic charge-discharge (GCD) tests revealed the capacitive properties of Co3O4 with the highest specific capacitance of 761.25 F g−1. The specific capacitance of Co3O4 nanoparticles was found to be 761.25 F g−1 at 11 mA/cm2 current density. The Co3O4 nanoparticles were synthesized by a simple sol–gel method. The crystallite size of Co3O4 nanoparticles was found to be 13.76 nm. The specific capacitance of Co3O4 nanoparticles was found to be 761.25 F g−1 at 11 mA/cm2 current density. The Co3O4 nanoparticles were synthesized by a simple sol–gel method. The crystallite size of Co3O4 nanoparticles was found to be 13.76 nm.
Enhancing pseudocapacitive properties of cobalt oxide hierarchical nanostructures via iron doping
Heliyon, 2023
Through co-precipitation and post-heat processing, nanostructured Fe-doped Co 3 O 4 nanoparticles (NPs) were developed. Using the SEM, XRD, BET, FTIR, TGA/DTA, UV-Vis, and techniques were examined. The XRD analysis presented that Co 3 O 4 and Co 3 O 4 nanoparticles that had been doped with 0.25 M Fe formed single cubic phase Co 3 O 4 NPs with average crystallite sizes of 19.37 nm and 14.09 nm, respectively. The as prepared NPs have porous architectures via SEM analyses. The BET surface areas of Co 3 O 4 and 0.25 M Fe-doped Co 3 O 4 NPs were 53.06 m 2 /g and 351.56 m 2 /g, respectively. Co 3 O 4 NPs have a band gap energy of 2.96 eV and an extra sub-band gap energy of 1.95 eV. Fe-doped Co 3 O 4 NPs were also found to have band gap energies between 2.54 and 1.46 eV. FTIR spectroscopy was used to determine whether M-O bonds (M = Co, Fe) were present. The doping impact of iron results in the doped Co 3 O 4 samples having better thermal characteristics. The highest specific capacitance was achieved using 0.25 M Fe-doped Co 3 O 4 NPs at 5 mV/s, which corresponding to 588.5 F/g via CV analysis. Additionally, 0.25 M Fe-doped Co 3 O 4 NPs had energy and power densities of 9.17 W h/kg and 472.1 W/kg, correspondingly.
IOP Conference Series: Materials Science and Engineering, 2017
In this work, Co 3 O 4 nanoparticles were synthesized by hydrothermal method at different temperatures. The synthesized Co 3 O 4 nanoparticles were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS) and nitrogen adsorption-desorption. The Co 3 O 4 nanoparticles prepared at the hydrothermal temperature of 140 ℃ and at the annealing temperature of 350 ℃ have a shorter crystal spacing distance associated to the (220) crystal planes, larger BET surface area and more bivalent cobalt on the surface than these of Co 3 O 4 nanoparticles prepared at higher hydrothermal temperature or higher annealing temperature. The supercapacitor performances of synthesized Co 3 O 4 nanoparticles were analysed by cyclic voltammograms (CVs), Galvano static charge/discharge (GCD) and the electrochemical impedance spectroscopy (EIS) in 6 M KOH aqueous electrolyte solution. The Co 3 O 4 nanoparticles produced at lower temperatures exhibit good pseudo capacitance behaviour. Also, owning to the low hydrothermal temperature and the annealing temperature of Co 3 O 4 nanoparticles, they can be relatively low cost in favour of a promising candidate for electrochemical supercapacitors.
Cubic spinel Co 3 O 4 nanoparticles with spherical (0D) and hexagonal platelet (2D) morphologies were synthesized using a simple solvothermal method by tuning the reaction time. XRD and HRTEM analyses revealed pure phase with growth of Co 3 O 4 particles along [111] and [110] directions. UV−vis studies showed two clear optical absorption peaks corresponding to two optical band gaps in the range of 400−500 nm and 700−800 nm, respectively, related to the ligand to metal charge transfer events (O 2-→ Co 2+,3+ ). Under the electrochemical study in two electrode assembly system (Co 3 O 4 /KOH/ Co 3 O 4 ) without adding any large area support or a conductive filler, the hexagonal platelet Co 3 O 4 particles exhibited comparatively better characteristics with high specific capacitance (476 F g −1 ), energy density 42.3 Wh kg −1 and power density 1.56 kW kg −1 at current density of 0.5 Ag −1 , that suited for potential applications in supercapacitors. The observed better electrochemical properties of the nanoporous Co 3 O 4 particles is attributed to the layered platelet structural arrangement of the hexagonal platelet and the presence of exceptionally high numbers of regularly ordered pores.
Electrochemical capacitance study on Co3O4 nanowires for super capacitors application
One-dimensional Co 3 O 4 nanowires have been prepared by utilizing the ordered mesoporous silica material SBA-15 as template. The results of transmission electron microscope (TEM) and N 2 adsorption-desorption characterizations show that the Co 3 O 4 nanowires possess a uniform size and a large Brunauer-Emmett-Teller (BET) surface area. Its electrochemical performance was investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques in various concentration of KOH solution. This nanomaterial shows a small resistance, a high specific capacitance (SC), and a strong cyclic stability. The maximal SC value of 373 FÁg -1 was obtained in 6 M electrolyte under the scan speed of 3 mVÁs -1 at the first CV cycle. After 500 CV cycles, the SC value is about 90% of the original value. It is considered that the short path of ion transfer given by nanomaterial brought on the great pseudo capacitance performance.
Fabrication and Characterization of Nanoporous Co Oxide (Co3O4) Prepared by Simple Sol-gel Synthesis
Physical Chemistry Research, 2016
Cobalt oxide (Co 3 O 4) nanorods were prepared by a simple co-precipitation method using ethanol solution of cobalt nitrate as precursor and cetyl trimethylammonium bromide (CTAB) as surfactant. Morphological properties of the nanoparticles were characterized. XRD measurement exhibited the structure of Co 3 O 4 nanocrystals for annealed samples. The SEM images revealed that the particles changed from spherical shape to rod-like shaped by increasing annealing temperature. The TEM results exhibited that the size of cobalt oxide nanoparicles decreased from 25 nm for as-made particles to 50 nm for annealed samples with increasing temperature. The FTIR analysis confirmed the functional group presents in the cobalt oxide nanoparticles. The sharp peaks in FTIR spectrum determined the purity of Co 3 O 4 nanoparticles and existence of CoO group. Absorbance peak of UV-Vis spectrum showed the band gap energy of 3.69 eV corresponding to wavelength about 335 nm for as-prepared samples and the band gap energy of 3.49 eV corresponding to wavelength about 355 nm for annealed Co 3 O 4 nanoparticles. The results of magnetic measurements indicated a good coercive field and saturation magnetism around 447.81 G and 17.295 emu g-1 , respectively.
High Performance Asymmetric Supercapacitor based on spinel Co 3 O 4 nanoparticles
We report a facile synthesis and characterization of spinel Co 3 O 4 nanostructures on its utilization as electrode material for asymmetric supercapacitors by co-precipitation method. The as-synthesized nanostructure was characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR) and Scanning electron microscopy(SEM). Electrochemical behaviour of the Co 3 O 4 electrode performance was characterized by cyclic voltammetry(CV) in 1 M KOH electrolyte using a three electrode system. Galvanostatic charge-discharge measurements made on the fabricated asymmetric supercapacitor gave a high specific capacitance of 17.33 F/g at a discharge current density of 0.2 A/g. Moreover, they showed an excellent cycle stability and better capacity retention of 92% after 2000 continuous charge-discharge cycles.
Journal of Materials Engineering and Performance, 2018
A simple hydrothermal process was used to design self-assembled Co 3 O 4 nanoparticles in nanorod structure in the presence of graphene oxide as a template. The as-prepared Co 3 O 4 sample in a loose powder form was calcined at 450°C to get the well-crystalline phase of the same compound. The obtained Co 3 O 4 powder sample was characterized by using the powder XRD and SEM. The XRD pattern shows totally nine distinct reflection peaks of (111), (220), (311), (222), (400), (422), (511), (440), and (533) planes. The most intense peaks were chosen to evaluate the structural parameters. The lattice parameters (a), volume (V), and density (q) of the samples are 8.09 Å , 529.47 Å 3 , 6.06 g/cc, which are comparable to the value of lattice parameter (a = 8.056 Å), volume (V = 528.30 Å 3), and density (q = 6.055 gm/cc) for bulk Co 3 O 4. The average size of the Co 3 O 4 nanoparticles is 14 nm which is smaller than the SEM size of 50 nm corresponding to the agglomeration of tiny particles. Further, the formation of Co 3 O 4 nanoparticles were also confirmed by obtaining the band at 569, 1334,1337, 1566, and 3397 cm 21 in FTIR spectrum. Totally five characteristics peaks from Co 3 O 4 at 182.57, 456.49, 505.84, 605.80, and 618.02 cm 21 and peaks from GO-Co 3 O 4 at 182.57, 483.44, 505.84, 605.80, and 618.02 cm 21 corresponding to F 2g , E g , F 2g , F 2g, and A g modes of the crystalline Co 3 O 4 , respectively, in the Raman spectra. In the case of GO-Co 3 O 4 composite, lowintensity peaks of D and G bands are observed. The specific capacitance in rGO-Co 3 O 4 nanocomposite is about 65.15 Fg 21 .
Authorea (Authorea), 2023
Supercapacitors can be useful in many fields of modern technology due to their high energy storage capacity and fast chargedischarge cycle. It is replacing conventional electrical energy storage devices such as capacitors and batteries. The supercapacitor electrodes are efficient for sustainable energy storage and conversions due to their long lifespan and high cyclic rate. Recently, supercapacitors are used in every field of technology like transportation, consumer electronics, electrical instruments, wearable and portable devices, etc. Cobalt hydroxide thin films were prepared by the electrochemical deposition of CoCl2, Co(NO3)2, and Co(OAc)2 onto stainless steel (SS) substrate. The cobalt-based chemical compounds of 0.1M electrolyte solution is prepared in 100ml double distilled water at room temperature. Further, structural, morphological and capacitive properties were studied. In addition, the electrochemical characteristics of the obtained cobalt hydroxide thin films were determined experimentally to predict their application efficiency in advanced energy storage devices such as supercapacitors.