Supercapacitors (SCs) are gaining attention in energy storage due to their high-power density, rapid charge/discharge ability, and long life cycle. Improving these features relies on developing advanced electrode materials with better energy storage properties. This study explores UiO-66, a zirconium-based metal-organic framework (MOF), which offers advantages like a large surface area, tunable pore sizes, and stability. However, its poor electrical conductivity limits its use in supercapacitors. Herein, we applied the Hummers' method to oxidize UiO-66, creating an oxidized form, H-UiO-66, with enhanced conductivity. This material was characterized by various techniques, including SEM-EDX, XRD, XPS, FTIR, and BET analysis, while electrochemical tests (GCD, CV, and EIS) confirmed a significant improvement in specific capacitance-82.8 F g-1 for H-UiO-66 versus 0.18 F g-1 for pristine UiO-66 at 1 mA. These improvements stem from increased conductivity and electrochemical activity due to UiO-66 graphitization, highlighting the Hummers' method's effectiveness in transforming UiO-66 into a viable supercapacitor material.

The present work aimed to study the effect of single-sided UV-C successive exposures and sequential chemical etching on the different track parameters of bulk etch rate, Vb, detector diameter, D, detector length, L, track etch rate, Vt, detection sensitivity, and etched track shape. For this, PADC detectors initially irradiated with high energy-long range ions of 7 GeV Si and 17.48 GeV Ni were used. Fission fragment irradiations were also performed before UV-C exposure to determine the PADC bulk etch rate in exposed and non-exposed UV-C sides. Track parameters of bulk etch rate, Vb, detector diameter, D, detector length, L, track etch rate, Vt, and corresponding sensitivity were determined and compared on both sides. The relative differences between the track parameters on both sides are thus determined. It was found that exposure of PADC detectors to sequential UV-C followed by etching gives a strong increase in the two etching rates, Vb and Vt. Sensitivity measurements indicate that the rate of increase of Vb is greater than that of Vt. Track parameters data by direct track cone length and by indirect track diameter versus depth evidence the existence of two regions under the polymer surface. These two regions were attributed to the polymer crosslinking and degradation processes resulting from exposure to UV-C. Region 1 and Region 2 have different etching rates. Region 1 has a constant rate, while Region 2 has an increasing rate as it goes deeper. Sequential UV-C followed by etching makes it possible to generate unusual rocket-shaped (or amphora-shaped) tracks. One possible application of the described technique is the production of nuclear track membranes.

Manganese dioxide (MnO2) films are developed by potentiostatic electrodeposition on a stainless steel sheet as a current collector using manganese acetate tetrahydrate solution at a concentration of 0.25 mol L−1. The deposited sample layer is found to be amorphous as confirmed by the scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses. The capacitive property of the prepared electrodes is characterized by charging/discharging, cyclic voltammetry, and electrochemical impedance spectroscopy techniques in four different aqueous solutions; sodium sulfate, magnesium acetate, nickel acetate, and a mixture of sodium chloride + sodium bicarbonate + borax. Charge–discharge curves reveal higher specific capacitance (Cs) of 1580 F g−1 at 0.5 mA cm−2 for the investigated MnO2 film which is characterized in Ni acetate aqueous solution. The structural, morphological, and electrochemical properties of the electrodeposited manganese oxide films are also studied. The results indicate that the specific capacitance of the deposited samples showed a strong dependency on the electrolyte aqueous solutions, resulting in developing new electrolytes which is a top priority effort in comparison to seeking new electrode materials. It is found that the matching between the pore size structure of the electrode and the ion size of the electrolyte is of great importance for the improved capacity of prepared capacitors.

As a universal demand due to global water scarcity, capacitive deionization (CDI) has emerged as an energy-effective, eco-friendly desalination technology for removing dissolved salts from brackish water by forming electric double-layers through adsorption onto electrode surfaces, and there is a potential direction to be used for desalination of drinking water. It is still necessary to enhance desalination performance to desalinate raw salty water. In this work, commercial activated carbon electrodes were prepared for investigation in a CDI cell for water desalination with a minimum required construction at two different masses, and the investigated cells were subjected to 25 cycles of adsorption and desorption (each cycle 800 s) in a direction to investigate the deep cycles of stability and refreshment methods. The CDI cell with low-mass electrodes shows a higher electrosorption capacity of 33.77 mg/g using NaCl solution with an initial concentration of 870 ppm at the applied voltage of 2 V. An interesting refreshment behavior was observed and investigated for the high-mass cell electrodes after stability measurement for 25 cycles using different strategies. This refreshment behavior will open the route for more understanding of the ion’s kinetics by adsorption and desorption on the electrode surfaces and the changes in the electrode structures. This paper presented a relatively simple and easily scalable treatment for recovering the stability of the capacitive deionization cells and demonstrated the great potential of its use in water desalination applications.

Annular energy distribution, AED is a new concept deduced from radial dose, RDD that enables one to draw a map of energy-dose distribution around the ion's path at the nanometer scale better than the ordinary radial dose. The distribution of energy for different equal LET groups of ions of the same LET (keV/μm) were studied using this concept. Annular energy distributions, AEDs for 185 ions impeded in water medium were studied using Katz radial dose formula. AED was calculated using Butts-Katz and Tabata electron range-energy (R-E) relations and were compared. AED and shell annular energy distribution, SAED for those ions were mapping and confirming that energy distributions for ions of the same LET are not the same. AED growth with annular width r=0.1(nm)⟶Rmin(nm) showing a peak at the maximum annular energy width, rMAEW. Butts-Katz and Tabata show same annular energy distribution peaks of the same value, however, Tabata shows that energy is distributed over a wide range than Butts-Katz. Thus, Butts-Katz R-E relation is recommended and considered. AED for the studied 185 ions shows a peak at certain width called the maximum annular energy width, rMAEW. This rMAEW showed a monotonic increasing function with ion's β2. The total annular energy distribution, TAED for the different ions were determined and it shows a linear increasing function of the ion's (Z*/β)2.

Activated carbon granules present in our household filters used in water purification are significant waste. Activated carbon waste (ACW) was ground to a fine powder, then impregnation of SnO2 on ACW was performed under mild conditions followed by calcination of SnO2-ACW at 700 °C for 2 h, producing a SnO2-ACW hybrid composite. This hybrid composite material was used in the preparation of electrodes for supercapacitor and capacitive deionization applications. The electrochemical performance of the electrodes was investigated by using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. Calcination and addition of SnO2 contributed to an obtained electrode with a high specific capacitance of 30.46 F g-1 in a solution of 1 M Na2SO4 compared to the original ACW (0.122 F g-1) and calcined-ACW (1.42 F g-1) at an actual current of 1 mA. This electrode was also investigated for water desalination through the capacitive deionization technique and exhibited an electrosorption capacity of 6.44 mg/g compared to the commercial AC (8.9 mg/g) so it is a highly promising and economic electrode.

Double-layer capacitor electrode including activated carbon with multi-walled carbon nanotube as a conductive additive (AC/MWCNTs) and pseudocapacitor electrode with nano-structural porous manganese oxide (NP-MnO2) were prepared and used to improve the capacitive performance of the negative (N−ve) and positive (P+ve) electrodes for asymmetric hybrid supercapacitor. The investigated asymmetric NP-MnO2//AC/MWCNTs hybrid supercapacitor device was assembled with positive and negative electrodes using tissue paper as a separator. Galvanostatic charge–discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) techniques were employed for measuring the electrochemical characterization of the individual electrodes and supercapacitor cell. The specific capacitance of the NP-MnO2 positive electrode and the AC/MWCNTs negative electrode was 333 F g−1 at 5 A g−1 and 250 F g−1 at 0.5 A g−1, respectively. Furthermore, after 1000 CV cycles and 2000 GCD cycles, the positive and negative electrodes demonstrated superior stability of cycles with capacitance retention of 100%. The asymmetric NP-MnO2//AC/MWCNTs hybrid supercapacitor device manifests a wide working potential window (0–1.8 V) and highest specific energy of 50 Wh kg−1 with a specific power of 1085 W kg−1 at 1 A g−1. After 10,000 cycles at 12 A g−1, an excellent cycling stability behavior with 95% capacitance retention was obtained.

Halogenated Bromide (Br −) was subsequently dosed to aqueous electrolyte solution to enforce the capacitance features of activated carbon (AC) electrodes in electric double-layer supercapacitor devices for electrical energy storage. Physicochemical properties for AC with sodium sulfate (Na2SO4) and KBr redox additive were assessed by different characterization tools such as XRD, SEM, EDS, surface roughness, and BET techniques. Cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), electrochemical impedance spectroscopy (EIS), and the stability after 1000 cycles have been used to monitor the electrochemical behaviors of the prepared electrodes. The presence of halogen atom exhibited large faradaic resembling battery like-type in charge–discharge curves. In the aqueous solution, the investigated electrode showed a high specific capacitance of 957.8 F g−1 at a specific current of 0.46 A g−1 using a certain concentration of KBr added to Na2SO4. The single AC electrode showed specific energy of 133 Wh kg−1 and specific power of 859.6 W kg−1. Besides, the AC electrode displayed excellent long-term stability in Na2SO4@KBr electrolyte, preserving retention capacitance of 174%. AC/AC symmetric supercapacitor cell demonstrated excellent electrochemical performance, including specific energy of 57.15 Wh kg−1, specific capacitance of 127 F g−1, specific power of 5262 W kg−1 at a specific current of 3.8 A g−1, and 82.8% capacitance retention after 10,000 cycles.

Manganese dioxide thin films are prepared by anodic potentiostatic electrochemical deposition on etched stainless-steel substrates as a single supercapacitor electrode. Effects of different mass loadings of 25, 50, 100 µg/cm2 for manganese dioxide films deposited on stainless-steel current collector, and concentrations of Na2SO4 electrolyte solution in the range, from 0.1 to 0.9 mole/L, on the specific capacitance of the developed electrode are investigated using the cyclic voltammetry, galvanostatic charging-discharging curves, and electrochemical impedance spectra. The highest specific capacitances (484.7, 483.4 and 481.1 F/g) are obtained at 20 A/g (or 0.5 mA/cm2) with the electrode having mass loading of 25 µg/cm2 at 0.1, 0.3 and 0.7 mole/L of Na2SO4 electrolyte concentrations, respectively. This paper gives new vision on the charge storage mechanism in manganese dioxide/stainless-steel film as an active supercapacitor electrode material, and its transition between the pseudo-capacitive and double layer behaviors as an effect to the mass loading of the manganese dioxide film, and Na2SO4 electrolyte concentration.

The structural properties and capacitive behavior of manganese dioxide (MnO 2 ) films prepared by potentiostatic cathodic deposition were examined in presence and absence of pre-electrophoretically deposited reduced graphene oxide (rGO) film. The FTIR analysis reflects the formation of a MnO 2 /rGO composite film structure. SEM and TEM characterization show that the MnO 2 film deposited on rGO film has finer and less compact nanostructure and grown as sparsely aggregated particles follow the open structure of underlying rGO platelets. The specific capacitance and rate capability of MnO 2 /rGO film are higher than that of pristine MnO 2 film; it exhibits specific capacitance of 292 Fg -1 at 1 mA cm -2 and better cyclic stability at 3 mA cm -2 . The presence of 3D underlying defective rGO film creates an open structure with larger area, facilitates the electron transfer and access of the electrolyte ions through the surface of MnO 2 film and hence offering the potential of the unique capacitive behavior.

Shape and size of micro-tubes produced by high energy Au, Ni, Si and Fe ions on thick CR-39 polymer processed in strong etching solution were studied. Deep internal polymer track parameters of sensitivity (V); bulk (V-b) and track etch rates (V-t) were intensively investigated by measuring the track opening as well as the track cone length. Development of track envelope with etching was studied using track profile technique, TPT. Variations in V-b, V-t, and V with deep depth inside the polymer were studied down to approximate to 100 mu m depth or more. CR-39 sensitivity was reduced to 60-70% at the first 25 mu m inwards. Microphotographs for the developed track profile for each ion was shown. Fe and Si profiles show new and interesting track profile for the first time where their profiles deviate from the normal cone shape of the track. Ion's track membranes (TMs) for thick CR-39 polymer were produced and their properties were determined.

Bulk etch rate of PADC CR-39 detector in a mixture of NaOH and ethanol alcohol aqueous solution of (8 ml of NaOH + X ml of ethanol: X = 0, 1, 2, 3) at 70 degrees C was determined using fission track diameter method. Wide range of NaOH concentration, never covered before, from 2 to 30 N was studied. Higher NaOH concentrations and ethanol increase the detector etching rate dramatically leading to a reaction rate far from equilibrium. Arrhenius and multi hit equations are no longer hold and therefore a need for new equations is arise. Viscosity of (NaOH + ethanol) in such wide concentration range was also studied at different temperatures to explain the reaction rate. Many efforts and different fitting equations were used to manipulate the data. Some of these equations are statistically as well as chemically rejected and finally three equations seem to read the data quit well are suggested.

Alkali-Silica Reaction (ASR) is considered one of the most significant critical internal deterioration mechanisms for concrete. ASR produces internal stresses that causes expansion and extended cracks threatening the country's wealth of existing infrastructure. Since ASR recognition in 1940 by Stanton, many studies had been conducted to evaluate the degree of reactivity for different types of gravel. However, limited research has focused on studying the effect of specimens’ shape and size, and casting direction on the accuracy of measured ASR expansion and find a correlation between cylindrical and standard prismatic specimens. Moreover, few studies have attempted to evaluate the optimum expansion level for controlling ASR expansion by strengthening ASR-damaged concrete. An experimental work divided into three phases was conducted to evaluate; (1) The effect of these new approaches on ASR expansion using fused silica (FS) as a fast-acting material, (2) The selection of a suitable jacketing materials based on target performance rather than focusing only on the achieved strength investigating concrete mixtures incorporating four types of fibre and fine crumb rubber aggregates (FCRA) with and without silica fume, (3) The effectiveness of six different strengthening materials as CFRP, BFRP, mortar with GG mesh, mortar with BFRP mesh, FRC, and CRC with BFRP to suppress ASR expansion, and evaluate sensitivity of strengthening time and testing time vs. the strengthening types on the concrete mechanical properties. The results exhibited addition of FS caused a drastic increase in the expansion, and plays a crucial role to adversely affect concrete mechanical properties and durability index until age 180 day, then the effectiveness decreased until 548 days. Specimen geometry and size, and casting direction had a significant effect on the rate of expansion. Cylindrical specimens expanded at a higher rate than the prisms until 56 days in the range from 43% to 37%, and from 9% to 15% at 90 days until test termination at 548 days. Specimens cast vertically exhibited an increase in expansion over the others cast horizontally in the range from 2.63% to 8.41%. Specimens O100×200mm reveal lower expansion in the range from 5.89% to 9.52% than specimens O75×285mm. Concrete mixtures incorporating steel, macro, and micro polypropylene, micro nylon fibres, and FCRA with and without SF were examined. Based on balancing between mechanical properties, durability indices, and electrical resistivity, FRC incorporating micro polypropylene with SF, and CRC contained FCRA with silica were selected as FRC and CRC jacketing. Strengthening type, strengthening time, and testing time after applying strengthening materials showed a significant effect to control ASR expansion and enhanced the damaged concrete properties. For instance, CFRP exhibited a significant reduction in expansion compared to that with control specimens and followed by BFRP, CRC with BFRP, Mortar with GG, Mortar with BFRP, and FRC, respectively. Moreover, strengthening at early ages revealed decreases mechanical properties as a result of high residual expansion. However, testing at early ages showed higher results proved the exposure conditions had an adverse effect on the strengthening materials.

MnO2-chitosan hybrid nanocomposite films with low and high chitosan's molecular weights are synthesized by one-step cathodic electrodeposition on nickel foam substrate for electrochemical capacitors (ECs) application. The films have been characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), fourier transform infrared (FTIR) spectroscopy, cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The MnO2-chitosan hybrid nanocomposite films show better specific capacitance and rate capability than chitosan-free MnO2 film. For the MnO2-chitosan composite films, the highest specific capacitance is 424 F g(-1) obtained at a current density of 1 mA cm(-2). The deposited film retains a very stable capacitance over 400 cycles by charging and discharging at 3 mA cm(-2), and only 3% capacity loss is observed. The presence of chitosan promotes both ion and electron transport in the matrix of MnO2. Besides, it allows the formation of porous and crack-free deposited films. A deposition mechanism for MnO2-chitosan hybrid nanocomposite films is proposed. (C) 2013 Elsevier B.V. All rights reserved.

MnO2/carbon nanowalls electrode with a specific capacitance of 1170 F g−1, energy density of 162.5 W h kg−1and power density of 915.7 W kg−1.

MnO2/graphene electrode was developed via anodic deposition of nanostructured MnO2 film on electrophoretically reduced graphene oxide (EPD-rGO) film. The electrodeposited MnO2, EPD-rGO and MnO2/EPD-rGO electrodes were characterized and investigated for supercapacitor application using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, fourier transform infrared spectroscopy, cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. The electrophoretic deposition enables the development of rGO film composed of overlapped platelets of defective graphene sheets. The MnO2/EPD-rGO electrode shows better specific capacitance and rate capability than MnO2 electrode; it exhibits specific capacitance of 822 Fg(-1) and better cyclic stability at a current density of 1 mA cm(-2). The large surface area and defective nature of EPD-rGO film in conjunction with an efficient utilization of MnO2 nanoparticles facilitated rapid ion transport and electrochemical cyclic stability, and hence offering the potential of the unique capacitive behavior. The obtained results indicate electrophoretic deposition could set a facile base for providing graphene-based materials, at room temperature without using harsh and toxic chemicals or high synthesis temperature.

Amorphous MnO2/carbon nanowalls composite films are developed for the supercapacitor applications. Synthesis of carbon nanowalls template is performed by plasma-enhanced chemical vapor deposition in a CO/H-2 microwave discharge system. A well dispersion of amorphous MnO2 domains throughout carbon nanowalls template is obtained by potentiostatic anodic deposition technique. Carbon nanowalls enable to improve the capacitive behavior and rate capability of MnO2, a specific capacitance of 851 F g(-1) at a current density of 1 mA cm(-2) and charge transfer resistance of 1.02 Omega are obtained. MnO2/carbon nanowalls composite film exhibits energy density of 118 wh kg(-1), power density of 783 wh kg(-1), and capacitance retention of 92% after long cycle life of 2000 cycles by charging and discharging at 3 mA cm(-2). The high density of atomic scale graphitic edges and large surface area of carbon nanowalls in conjunction with the presence of amorphous MnO2 domains facilitate rapid electron and ion transport and hence offering the potential of the improved capacitive behavior. (C) 2013 Elsevier B.V. All rights reserved.

Amorphous manganese dioxide thin films were prepared by galvanostatic cathodic deposition at current densities of 0.5-1 mA/cm 2 on etched stainless-steel substrate from 20 mM KMnO4 solution. The structure of the deposited oxides was investigated using X-ray diffraction analysis. The capacitive behavior of the manganese dioxide electrodes was characterized by cyclic voltammetry and electrochemical impedance spectroscopy in 0.5 M Na2SO4 electrolyte. The capacitive performance was found to increase with the increase in the deposition current density. The electrode deposited at current density of 1 mA/cm 2 showed specific capacitance of 174 F/g at a scan rate of 10 mV/s, equivalent series resistance of 3.53 Ω, and charge transfer resistance of 1.39 Ω. The improvement in the capacitive behavior of the electrode with the increase in the deposition current density was attributed to the increase in the electronic properties of the deposited oxides.

Nano-structured MnO2-chitosan hybrid composite electrodes containing low and high chitosan's M-w were synthesized by one-step cathodic electrodeposition on nickel foam substrate for electrochemical capacitors (ECs) application. The effect of chitosan molecular weight (M-w) on the structure and capacitive behaviour of the tailored electrodes was examined. The electrodes have been characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The presence of CH promotes both ion and electron transport in the matrix of MnO2. Furthermore, the use of CH with its inherent binding properties allowed the formation of adherent and cracks free deposits. The MnO2-chitosan hybrid nanocomposite electrodes showed better specific capacitance and rate capability than MnO2 electrode. The highest specific capacitance of 424 F/g was obtained for the MnO2-chitosan composite electrode with low chitosan's M-w at a current density of 1 mA/cm(2). The electrode retained a very stable capacitance over 400 cycles by charging and discharging at 3 mA/cm(2), as the capacity loss is only 3%, indicative of long term electrochemical cycling stability.