Abstract. In this communication, we explore the cobalt based metal–organic-frameworks (Co-MOF) as a promising material for supercapacitors. The doctor bladed Co-MOF film exhibits a good pseudocapacitor behavior with the specific capacitance up to 206.76 F g-1. The electrochemical redox switching is reversible perfectly for a long run which leads to the loss of only 1.5% in capacitance fo…
Abstract: Nanocarbon/polyaniline (PANI) composites were prepared by in situ polymerization of aniline on carbon blacks (CB), carbon nanotubes (CNTs) and graphene nanosheets (GNSs). The GNS/PANI composite has the highest PANI content with high specific capacitance, low internal resistance as well as improved cycling stability and rate capability. Of the three, the GNS/PANI composite shows bett…
Abstract. Nitrogen-doped microporous carbons (N-MCs) were prepared by the carbonization of the polyvinylidene fluoride (PVDF)/melamine mixture without chemical activation. The electrochemical performance of the N-MCs was investigated as a function of PVDF/melamine ratio. It was found that, without additional activation, the N-MCs had a high specific surface area (greater than 560 m2/g) beca…
Abstract. Mesoporous binary nickel–cobalt (Ni–Co) oxy-hydroxides have been obtained through the microwaveassisted hydrothermal annealing (MAHA) method. The porosity control of the nanostructured Ni–Co oxy-hydroxide nanoparticles is achieved through adding the pluronic triblock copolymer F127 as the surfactant. The structural and electrochemical properties of porous Ni–Co oxy-hydroxi…
Abstract. Nano-porous oxide layers on the surface of 302-type stainless steel were synthesized by galvanostatic anodization process carried out at two current densities, 7 and 15 mA cm-2 for the time periods of 15 and 30 min. A relatively thinner (~300 nm) and compact oxide layer formed when anodization was performed at a current density of 7 mA cm-2. However, with increase in anodization…
Abstract. Dispersed Na0.6CoO2·yH2O and Li0.5CoO2 powders have been obtained at room temperature by rapid precipitation in aqueous solutions of LiOH or NaOH in the presence of a strong oxidizer. The precipitates are well crystallized and consist of nanoscale platelets with high specific area (above 100 m2/g). The Li0.5CoO2 phase is stable in aqueous electrolytes whereas the Na0.6CoO2·yH2O …
Abstract. A porous nanowall Co3O4 film is prepared by a facile cathodic electrodeposition. The as-prepared porous nanowall Co3O4 film shows a net-like porous structure with huge porosity. The porous network is made up of free standing interconnected Co3O4 nanoflakes with a thickness of 20 nm. As cathode material for pseudocapacitors, porous nanowall Co3O4 film exhibits weaker polarization, …
Abstract. Multi-walled carbon nanotubes grown on the carbon paper substrate are prepared by in situ growth in a chemical vapor deposition system. Co(OH)2 is deposited on carbon nanotubes/carbon paper by electrodeposition methods. SEM images show that the successful growth of nanometer-sized Co(OH)2 nanosheets on the surface of carbon nanotubes/carbon paper substrate. The electrodes of Co(OH…
Abstract. A precipitation method is proposed for the synthesis of nanostructured Mn oxide in the use of supercapacitor electrodes. Here, ethanol is used as a solvent, instead of water. The nanostructured Mn oxide synthesized has been characterized by various analytical methods. Experimental results reveal that the alkyl chain of ethanol plays an important role in forming the nanostructured Mn …
Abstract. A porous net-like -Ni(OH)2/γ-NiOOH composite film is prepared by a chemical bath deposition. The as-prepared porous composite film shows a highly porous structure built up by many interconnected nanoflakes with a thickness of about 20 nm. The pseudocapacitive behavior of the porous composite film is investigated by cyclic voltammograms (CV) and galvanostatic charge–discharge …
Abstract. A simple method for activating polyaniline (PANI) using NH3 for the synthesis of high performance electrode materials in supercapacitors is described. The PANI is activated at various temperatures (750–1050 ◦C) with a mixed stream of NH3 and N2. Because of the corrosive properties of NH3, the surface area of PANI (46.6 m2 g−1) is significantly increased up to 1719.8 m2 g−1…
Abstract. Nanoparticles of the Li–Ti–O precursors have been prepared using a reverse micelle method. Transmission electron microscopy (TEM) analysis showed that the precursor had an amorphous structure. The average diameter of the amorphous Li–Ti–O particles was approximately 5 nm (within a range of ±2 nm). X-ray diffraction measurement (XRD) results showed that the conversion of th…
Abstract. A nanostructured Ni(OH)2 electrode was prepared and evaluated in supercapacitor application. Mesoporous Ni(OH)2 tubes were integrated onto carbon fiber paper without the use of a binder. The large surface area and porous structure of Ni(OH)2 combined with the effective diffusion of electrolytes through carbon network resulted in an excellent charge storage capacity and good long-t…
Abstract. The exciting development of advanced nanostructured materials has driven the rapid growth of research in the field of electrochemical energy storage (EES) systems which are critical to a variety of applications ranging from portable consumer electronics, hybrid electric vehicles, to large industrial scale power and energy management. Owing to their capability to deliver high power…
Abstract. NiO nanofibers modified by citric acid (NiO/CA) for supercapacitor material have been fabricated by electrospinning process. The characterizations of the nanofibers are investigated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Electrochemical properties are characterized …
Abstract. A series of uniform composite networks consisting of CuO nanosheets (NSs)/single-wall carbon nanotubes (SWCNT) were fabricated through a facile and green method with the aid of electrostatic interaction in aqueous solution. The capacitance was investigated by using various electrochemical methods including cyclic voltammetry (CV), constant-current galvanostatic charge/discharge cu…
Abstract. In the present study, ZnO-doped manganese (Mn) oxide coatings were prepared as a function of ZnO content (≤40 at.%) by sol–gel process. After post heat treatment at 300 °C, the influences of ZnO on the microstructural characteristics and pseudocapacitive performance of the Mn-oxide films were investigated. The structural analyses identified the sol–gel ZnO-doped Mn-oxide powd…
Abstract. Hierarchical porous carbon anode and metal oxide cathode are promising for supercapacitor with both high energy density and high power density. This Letter uses NiO and commercial carbon nanotubes (CNTs) as electrode materials for electrochemical capacitors with high energy storage capacities. Experimental results show that the specific capacitance of the electrode materials for 10…
Abstract. Flexible supercapacitors show a great potential for applications in wearable, miniaturized, portable, largescale transparent and flexible consumer electronics due to their significant, inherent advantages, such as being flexible, lightweight, low cost and environmentally friendly in comparison with the current energy storage devices. In this report, recent progress on flexible supe…
Abstract. A superior electrode for high-performance supercapacitors has been designed by growing homogeneous NiO nanoparticles on conductive Ni foam substrate through a facile two-step method. The preparation strategy involves the electrodeposition of nickel hydroxide precursor on Ni foam and subsequent low temperature annealing process. These NiO nanoparticles are interconnected with each …
Abstract. The nanoporous RuO2·3.38H2O was synthesized with a surfactant template using sodium dodecyl sulfate. The surface area of the material amounted to 220 m2 g−1 while the maximum specific capacitance obtained was 870 Fg−1 at a scan rate of 10 mV s−1. The specific capacitance of nanoporous RuO2·3.38H2O electrode exhibits enhancement, compared with other porous RuO2 materials sy…
Abstract. Ordered porous carbon with pore size of 80 nm (C80) was treated in concentrated nitric acid to investigate the effect of the functional groups on the electrochemical properties in supercapacitors. The optimum oxidation time for C80 with good supercapacitive performance in acidic and basic electrolytes was determined. The increase of nitrogen and oxygen groups in the surface result…
Abstract. MnO2 nanoparticles (NPs) with 1.8±0.2 nm in diameter were successfully produced using an ethylene glycolassisted synthesis with successive hydrolysis and condensation reactions. The tiny NPs were used as precursors for producing three-dimensionally ordered macroporous (3DOM) electrodes using a colloidal crystal-templating method. The specific capacitances of 3DOM MnO2 electrodes dep…
Abstract. This study is intended to determine if the capacitive properties are improved when a specific amount of crystalline ruthenium oxide (c-RuO2) is added to an amorphous hydrous ruthenium oxide (a-RuO2) electrode fabricated by the spark plasma sintering technique. For at the cyclic voltammetry scan rates higher than 10 mV s−1, the capacitance of a highly pseudo-capacitive, but less …
Abstract. NiO–MnO2/MWCNT composite was formed by a simple chemical precipitation method using a chelating agent and Ni and Mn hydroxides on MWCNT. The NiO–MnO2/MWCNT was pretreated by ultrasonication, followed by thermal annealing at 300 ◦C. The material obtained was applied as an electrode in a supercapacitor. FT-IR, EDS, XRD, FE-SEM and FE-TEM were used to characterize the structura…
Abstract. A novel 3D nanostructure consisting of Ni(OH)2 nanoparticles, carbon nanotubes (CNTs), and reduced graphene oxide with an extremely high electrocapacitance is described. The nanostructure consists of CNTs with embedded Ni(OH)2 nanoparticles as pillars for reduced graphene oxide sheets. Electrochemical results show that the composite displays specific capacitances as high as 1235 a…