Abstract:Core/shell structures of carbon-based materials/ metal oxide have been considered as potential candidates for electrochemical devices due to their improved pseudocapacitance/electrical double layer capacitance and high conductivity/ superior surface area. The development of multiple coreshell structures of MWCNT@MnO 2 @PPy was analyzed as a standard procedure for mass production of supercapacitor electrodes. The relative concentration of carbon nanotubes in the composite was varied to optimize the double layer… Show more
“…The polymerization of pyrrole on the surface of α-MnO 2 nanorods enhanced the surface coverage of C-Dots and as a result particle thickness of the rods increased, as clearly be seen in the SEM images shown in Fig. S3d,e 31 , 95 . Figure 6 ( a ) Schematic illustrations of the synthesis method of α-MnO 2 /PPy/C-Dot green hybrids from pre-synthesized α-MnO 2 nanorods and representing scanning electron microscope images.…”
Multi-colored, water soluble fluorescent carbon nanodots (C-Dots) with quantum yield changing from 4.6 to 18.3% were synthesized in multi-gram using dated cola beverage through a simple thermal synthesis method and implemented as conductive and ion donating supercapacitor component. Various properties of C-Dots, including size, crystal structure, morphology and surface properties along with their Raman and electron paramagnetic resonance spectra were analyzed and compared by means of their fluorescence and electronic properties. α-Manganese Oxide-Polypyrrole (PPy) nanorods decorated with C-Dots were further conducted as anode materials in a supercapacitor. Reduced graphene oxide was used as cathode along with the dicationic bis-imidazolium based ionic liquid in order to enhance the charge transfer and wetting capacity of electrode surfaces. For this purpose, we used octyl-bis(3-methylimidazolium)diiodide (C8H16BImI) synthesized by N-alkylation reaction as liquid ionic membrane electrolyte. Paramagnetic resonance and impedance spectroscopy have been undertaken in order to understand the origin of the performance of hybrid capacitor in more depth. In particular, we obtained high capacitance value (C = 17.3 μF/cm2) which is exceptionally related not only the quality of synthesis but also the choice of electrode and electrolyte materials. Moreover, each component used in the construction of the hybrid supercapacitor is also played a key role to achieve high capacitance value.
“…The polymerization of pyrrole on the surface of α-MnO 2 nanorods enhanced the surface coverage of C-Dots and as a result particle thickness of the rods increased, as clearly be seen in the SEM images shown in Fig. S3d,e 31 , 95 . Figure 6 ( a ) Schematic illustrations of the synthesis method of α-MnO 2 /PPy/C-Dot green hybrids from pre-synthesized α-MnO 2 nanorods and representing scanning electron microscope images.…”
Multi-colored, water soluble fluorescent carbon nanodots (C-Dots) with quantum yield changing from 4.6 to 18.3% were synthesized in multi-gram using dated cola beverage through a simple thermal synthesis method and implemented as conductive and ion donating supercapacitor component. Various properties of C-Dots, including size, crystal structure, morphology and surface properties along with their Raman and electron paramagnetic resonance spectra were analyzed and compared by means of their fluorescence and electronic properties. α-Manganese Oxide-Polypyrrole (PPy) nanorods decorated with C-Dots were further conducted as anode materials in a supercapacitor. Reduced graphene oxide was used as cathode along with the dicationic bis-imidazolium based ionic liquid in order to enhance the charge transfer and wetting capacity of electrode surfaces. For this purpose, we used octyl-bis(3-methylimidazolium)diiodide (C8H16BImI) synthesized by N-alkylation reaction as liquid ionic membrane electrolyte. Paramagnetic resonance and impedance spectroscopy have been undertaken in order to understand the origin of the performance of hybrid capacitor in more depth. In particular, we obtained high capacitance value (C = 17.3 μF/cm2) which is exceptionally related not only the quality of synthesis but also the choice of electrode and electrolyte materials. Moreover, each component used in the construction of the hybrid supercapacitor is also played a key role to achieve high capacitance value.
“…MC, mesoporous carbon. Moreover, hybrid materials such as carbon nanotubes/mesoporous carbon/MnO 2 [165], carbon nanotubes/3D graphene/MnO 2 [11], and carbon nanotube@MnO 2 @polypyrrole [12] have been developed. Table 4 shows the capacitance of exemplary composites based on carbon nanostructures and metal oxides.…”
This review is focused on the theoretical and practical aspects of electrochemical c a p a c i t o r sb a s e do nc a r b o nn a n o t u b e s .I np articular, recent improvements in the capacitance properties of the systems are discussed. In the first part, the charge storage mechanisms of the electrochemical capacitors are briefly described. The next part of the review is devoted to the capacitance properties of pristine single-and multi-walled carbon nanotubes. The major portion of the review is focused on the capacitance properties of modified carbon nanotubes. The electrochemical properties of nanotubes with boron, nitrogen, and other atoms incorporated into the carbon network structure as well as nanotubes modified with different functional groups are discussed. Special attention is paid to the composites of carbon nanotubes and conducting polymers, transition metal oxides, carbon nanostructures, and carbon gels. In all cases, the influences of different parameters such as porosity, structure of the electroactive layer, conductivity of the layer, nature of the heteroatoms, solvent and supporting electrolyte on the capacitance performance of hybrid materials are discussed. Finally, the capacitance properties of different systems containing carbon nanotubes are compared and summarized.
“…Hence, extensive researches have been focused to find proper electrode materials for SCs. Pseudocapacitors mainly store charges from reversible redox reactions and generally composed of transition metal oxides/hydroxides like tin oxide 2 , titanium oxide 3 , cobalt oxide 4,5 , nickel oxide [6][7][8] , vanadium oxide 9 , zinc oxide 10 , manganese oxides [11][12][13][14][15] , cobalt hydroxides [16][17][18][19][20] , nickel hydroxides [21][22][23][24][25] and iron oxides [22][23][24][25][26][27][28][29][30][31][32] . This type of SCs could deliver high specific capacitance, but present poor cycle stability.…”
A one-pot electrosynthesis platform is reported for fabrication of Y 3+ doped iron oxide nanoparticles (Y-IONPs). In this procedure, Y-IONPs are electro-deposited from an additive-free aqueous solution of iron(III) nitrate, iron(II) chloride and yttrium chloride. The analysis data provided by X-ray diffraction (XRD), field emission electron microscopy (FE-SEM) and energy-dispersive X-ray (EDX) confirmed that the deposited Y-IONPs sample is composed of magnetite nanoparticles (size≈20nm) doped with about 10wt% Y 3+ cations. The performance of the prepared Y-IONPs as supercapacitor electrode material was studied using cyclic voltammetry (CV) and galvanostat charge-discharge (GCD) tests. The obtained electrochemical data showed that Y-IONPs provide SCs as high as 190.3 and 138.9 F g −1 at the discharge loads of 0.25 and 1 A g −1 , respectively, and capacity retentions of 95.9% and 88.5% after 2000 GCD cycling. Furthermore, the results of vibrating sample magnetometer measurements confirmed better superparamagnetic behavior of Y-IONPs (Mr=0.32 emu g-1 and H Ci = 6.31 G) as compared with pure IONPs (Mr=0.95 emu g-1 and H Ci = 14.62 G) resulting from their lower Mr and Hci values. Based on the obtained results, the developed electro-synthesis method was introduced as a facile procedure for the preparation of high performance metal ion doped magnetite nanoparticles.
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