Aluminum Cathode Research Articles

Polarized polymer light-emitting electrochemical cells using polyfluorene and polycaprolactone blend film by floating-film transfer method

Abstract Sandwich-type structured polarized Polymer Light-emitting Electrochemical Cells (PLECs) of poly(9,9-dioctylfluorene) (PFO) successfully fabricated by combination of floating-film transfer method (FTM) and Post-blending ionic liquid (IL) procedure. An ion-solvating polymer, polycaprolactone (PCL), was blended in PFO for improving IL penetration. The PFO:PCL film showed clear optical dichroism due to the PFO backbone orientation. The IL, 1-Ethyl-3-methylimidazolium (trifluoromethylsulfonyl)imide (EMIm-TFSI), easily post-blended into the PFO:PCL blend FTM film without disordering PFO backbone orientation. The fabricated thickness varied PLECs with ITO anode and aluminum cathode were demonstrated distinct anisotropy, whole device area emission and low turn-on voltage compared to PLEDs.

Investigation of arc spot splitting behavior on aluminum, titanium, and their alloy cathodes under different gas flows

This paper presents an experimental study on the spot splitting behavior of aluminum, titanium, and their alloy cathodes during electric arc discharge. Utilizing high-speed digital cameras, we dynamically captured the splitting motion of cathode arc spots and analyzed their behavior under different pressures of argon, nitrogen, and oxygen. The study also examined the effects of pulsed arc current parameters on spot splitting. We observed a ringlike expansion of pulsed arc spots during splitting, with aluminum cathodes showing better performance than titanium in promoting spot splitting and stabilizing the subsequent motion of the split spots. Oxygen was found to enhance spot splitting more effectively than nitrogen. Furthermore, the parameters of the pulsed arc can control the extent of spot splitting and expansion. These findings provide valuable insights for optimizing arc parameter control in metal film deposition processes.

Study of burst mode for enhancing the ps-laser cutting performance of lithium-ion battery electrodes

The demand for lithium-ion batteries (LIBs) has increased significantly, leading to an increased focus on high quality production methods. In response to this growing demand, laser technology has been increasingly used for electrode notching and cutting. In addition, the advent of high-power ultrashort lasers equipped with burst mode capabilities represents a promising option for electrode cutting of LIBs. On the other hand, these types of lasers for this purpose are relatively unexplored in the literature. This study investigates the effect of various parameters, including the number of pulses per burst (ranging from 1 to 8), the pulse repetition rate (200.0, 550.3, and 901.0 kHz), and the burst shape (equal pulse peak and increasing pulse peak), on the laser cutting process of aluminum foil, cathode, copper foil, and anode. The results indicate that increasing the number of pulses per burst and the pulse repetition rate improves productivity and quality for all materials, with a more significant effect observed for metal foil than for cathode and anode materials due to the different laser-material interactions for metal foil and active material. The burst shape with equal pulse peaks was found to be a more suitable temporal distribution for cutting all materials compared to an increasing pulse peak distribution. The ablation efficiency was evaluated as a function of the peak fluence of a single pulse within the burst. The results emphasize that higher productivity at higher average power can be achieved by increasing the pulse repetition rate toward the MHz range with moderate pulse energies.

Performance improvement of ZnO quantum dot-based white light-emitting diodes enabled by an insulating passivation interlayer

In this work, solution-processed white quantum dot light-emitting diodes (WQLEDs) were demonstrated by using the zinc oxide quantum dots (ZnO-QDs) as both a white fluorescent emitter as well as an effective electron injection layer. Meanwhile, a thin insulating passivation layer of polystyrene (PS) was inserted between the ZnO-QDs layer and aluminum cathode to optimize the electron injection into the device and reduce the non-radiative recombination at the interface between ZnO-QDs layer and cathode. Our findings reveal that strategically incorporating a thin PS insulating passivation interlayer between the ZnO-QDs and the aluminum cathode effectively reduces the surface defects of the ZnO-QDs as well as the infiltration of metal atoms into the ZnO-QD layer. Consequently, the WQLEDs with such an insulating PS interlayer exhibit a high brightness of 1076 cd/m2, showing a great improvement of∼40 % compared with that of WQLEDs without PS passivation interlayer (780 cd/m2). This work provides an efficient method to realize single component WQLEDs, thus bringing a feasible solution for next-generation solid-state lighting technologies.

PERFORMANCE EVALUATION OF A SIMPLE ELECTROCHEMICAL TREATMENT MODEL FOR SALINE WASTEWATERS: PART A

This paper investigated the performance of the electrochemical treatment technique in removing chloride from saline (salty) wastewaters (brine). Saline wastewaters (between 10 x 103 mg/l and 40 x 103 mg/l of chloride) were prepared and subjected to electrochemical treatment using developed carbon–resin (anode) and aluminium (cathode) electrodes. Electrochemical treatment of the simulated brine was conducted on a laboratory scale. The influence of selected factors on the performance of the electrochemical process was monitored using fractional factorial experiments. These selected factors were optimized using steepest descent technique (between the minimum and maximum concentrations) and rate change of chloride removal efficacy through Microsoft Excel Solver. The optimum values of these selected factors were used to purify typical raw saline water. Efficacies of the process in removing chloride ions from the typical raw saline water was used to predict efficacy of the system using typical chloride concentration in seawater based on literature and previous studies. The study revealed the relationship between chloride removal efficacy (%), initial concentration of chloride, current through the wastewater and separation distance between the electrodes were best in the form of exponentials with coefficient of determination of 0.979, 0.920 and 0.977, respectively. The optimum values of these selected factors such as current, pH, treatment period and separation distance between the electrode (centre to centre of the electrode) were 10.5 A equivalent to 0.795 A cm-2 , 6.7, 2.75 hr and 42mm, respectively. It was concluded that electrochemical treatment with carbon electrodes is an effective tool for removing chloride from saline wastewater during electrochemical treatment.

The impact of a ZnO space layer on enhancing the efficiency of P3HT: PCBM blend-based organic solar cells

The performance of Organic Solar Cells (OSCs) based on a composite photoactive of poly(3-hexylthiophene) (P3HT) and 6,6-phenylC61-butyric acid methyl ester (PCBM) as the donor and acceptor electrons, respectively, is examined in this paper through a simulation study. Optical Zinc oxide (ZnO) spacers between the active layer and the Aluminum (Al) cathode contact layer, serving as a hole transport layer (HTL), are compared to the usual configuration without a ZnO spacer in the second device construction. With and without the ZnO optical spacer, we calculate the electric field intensities and generation rates (G) for a range of incident wavelengths. Under AM 1.5 G at 100 mW cm−2 illumination and in the dark, the short-circuit current density (Jsc) is improved by up to 9.47% after adding the ZnO layer as an optical spacer. In addition, there is a gain of up to 11.42% in external quantum efficiency (EQE). Furthermore, the ZnO spacer layer device has a markedly higher incident photon-to-electron conversion efficiency (IPCE), going from 77% in the control device (without ZnO) to 90% with ZnO spacer layer. The numerical simulation results based on the finite element method (FEM) are consistent with the published experimental data.

Performance evaluation of a simple electrochemical treatment model for saline wastewaters: Part B

This paper investigated the performance of the electrochemical treatment technique in removing chloride from saline wastewater (brine) with the critical objective of purifying the wastewater, evaluated the efficacies of selected mathematical models and particular attention to selected polynomial regression models as a follow-up to previous studies. The saline wastewaters were prepared and subjected to electrochemical treatment using developed carbon–resin (anode) and aluminium (cathode) electrodes. Electrochemical treatment of the synthesised saline wastewaters (between 10 x 10^3 mg/l and 40 x 10^3 mg/l of chloride) was conducted on a laboratory scale. The influences of selected or picked-out operational factors on the functioning or efficacy of the electrochemical purification process of the wastewater were monitored using fractional factorial experiments. Three mathematical models were formulated using Microsoft Excel Solver and evaluated statistically. The study revealed that the current, the time and the interval distance between the electrodes were significant and vital factors that impacted on the performance of the electrochemical purification treatment of brine. The factors with negative special effects on the performance of the treatment process of brine were separation distance between the electrodes, pH, the depth of the electrode, the initial and primary concentration of the chloride and the flow and discharge rate of the wastewater. The performances or efficacy of the polynomial regression models in predicting the performance of the treatment technique were with average errors of 2.99 %, 2.97 % and 2.94% and accuracy of 97.01 %, 97.03 % and 97.06 % for Models A, B and C, respectively. It was concluded that the electrochemical treatment of brine with carbon-resin electrodes is efficient in removing chloride from brine and the selected models predicted the performance of the treatment technique well.

Evaluation of an Electrocoagulation Process Modified by Fenton Reagent

This article is oriented to the degradation of nickel in an ionic state at laboratory level from synthetic water made with nickel sulfate, using the electrocoagulation process with aluminum cathodes and modifying this process by the addition of the Fenton reagent, which results from the combination of hydrogen peroxide (H2O2) and ferrous sulfate (FeSO4) being this reagent a catalyst and oxo-coagulant agent, The efficiency of this reagent will be compared with the typical treatment with aluminum sulfate, which is a typical process based on ion exchange/coagulation at the same percentage concentrations as the Fenton reagent. For this purpose, the optimum conditions of the advanced electrocoagulation process were determined, which consisted of determining the concentrations of Fenton’s reagent at concentrations of 150 ppm, 300 ppm, and 450 ppm, in addition to the operating variables such as pH of 8 and 10, voltage of 17.5 V and 19 V and their reaction time, which were compared with aluminum sulfate at 300 ppm, 600 ppm, and 900 ppm. The results obtained with respect to the typical treatment were 0% nickel degradation. However, with the advanced oxidation treatment, an average reduction of 97.5% was found at the conditions of 19 V, pH 10, and Fenton 150 ppm in a time of 30 min.

A zinc porphyrin-amidine as a green carbon-based electron transport material for organic-light emitting diodes

Charge injection and transport interlayers based on artificial green carbon materials are imperative for a sustainable future of many classes of optoelectronic devices, including organic light-emitting diodes (OLEDs). Especially, porphyrin derivatives can act as efficient energy and charge funnels mimicking their successful photosynthetic function. Here, we report on the application of a novel green carbon material, in particular, a zinc porphyrin derivative bearing an amidine functional group (referred to as ZnP-amidine), as an electron transport material in fluorescent OLEDs based on a green-yellow co-polymer emitter. ZnP-amidine is processed from environmental friendly solvents without any annealing requirements thus being suitable for low-cost sustainable optoelectronics. It is applies as an ultra-thin interlayer between the aluminum cathode and the emissive layer to enable efficient electron transport and stable performance. This work paves the path towards low-cost green carbon materials inspired by natural processes for organic optoelectronics.

Evaluation of treatment and energy efficiencies of an advanced electrochemical system for Chlorella removal equipped with aluminum, graphite, and RGO nanoparticles-coated cathodes

Advanced material sciences and technologies can help to address environmental challenges in order to achieve sustainable development goals by developing innovative materials capable of mitigating energy consumption in treatment systems. In this study, an innovative electrocoagulation unit for algae removal was optimized, and the effects of various variables, including novel cathode materials (i.e., graphite and reduced graphene oxide nanoparticles), on treatment efficiency and energy consumption were evaluated. Reduced graphene oxide nanoparticles were synthesized and then immobilized on the graphite cathode surface with the modified Hummer's method. Stabilization of nanoparticles was achieved with polytetrafluoroethylene. The use of the reduced graphene oxide nanoparticles-coated cathode led to a significant decrease (42.93%) in energy consumption, compared to the case with an aluminum cathode. In the optimum conditions (a current density of 3 mA/cm2, an electrolyte concentration of 2 g/L, an electrode surface area of 56 cm2, a processing time of 60 min, and a sedimentation time of 30 min), the novel electrocoagulation unit, equipped with an aluminum anode and a reduced graphene oxide nanoparticles-coated cathode electrode, achieved removal efficiencies of 72.69% for Chlorella species and 72.96% for turbidity.

Measurement of the Photoelectron Yield from the Synchrotron Radiation for the NEG-coated Tubes

NEG-coated chambers have been adopted as the beam ducts for large particle accelerators and synchrotron light sources for the sake of the lower yields of the photon stimulated desorption (PSD) and the photoelectrons (PE) from the NEG films in addition to their pumping performance. Measurement of the photoelectron yield (PEY) was performed at the BL19B (PSD) beamline of the 1.5 GeV Taiwan Light Source (TLS) which simultaneously measures the PSD-yield. An aluminium cathode was inserted in the tubes and a positive bias of voltage for extraction of the photoelectrons applied. The PEY was obtained by dividing the photoelectron current by the photon flux of the synchrotron radiation. Measurements of the PEY include various types of NEG-coated stainless steel tubes and the bare tubes of titanium and aluminium alloys for the comparison. The experimental system and the results will be described in this presentation.

Application of electrocoagulation process for the treatment of reactive blue 19 synthetic wastewater: Evaluation of different operation conditions and financial analysis

The aim of this study was to treat reactive blue 19 (RB 19) in solution by electrocoagulation (EC) process, using aluminum cathodes modified by zinc oxide nanoparticles (ZnO-NPs). Cyclic voltammetry methodology (CVM) was used to investigate the effect of coating aluminum electrodes with ZnO-NPs. The response surface methodology (RSM) based on central composite design (CCD) and analysis of variance (ANOVA) were used to evaluate and optimize the variables and the response, which was dye removal efficiency. The economic and energy analyses confirmed that this process was a promising method for pretreatment and treatment of industrial textile wastewater.

(Best Student Presentation) Extending the NaCl-AlCl3 Phase Diagram to Enable Low-Cost, Long-Duration Na-Al Batteries for the Grid

Achieving deep grid decarbonization via intermittent renewable power sources requires extensive grid-scale energy storage technologies to deliver stable power during periods of low generation. Doing so at scale and at low cost further adds to this challenge, as current solutions generally rely on geographically limited solutions such as pumped hydro storage, or costly battery chemistries focusing primarily on Li-ion technologies. As an alternative, battery systems based on lower cost materials such as sodium offer an attractive alternative for low-cost, scalable, and non-geographically limited electrochemical energy storage.This work combines an abundant and inexpensive molten sodium metal anode with a cost-effective aluminum cathode to provide a proof-of-concept alternative for grid-scale energy storage. Building on prior work utilizing the high reversibility of the neutral sodium chloroaluminate (NaAlCl4) molten salt electrolyte commonly used for classic molten sodium batteries, this work demonstrates greater capacity utilization of the NaCl-AlCl3 binary system by ‘overcharging’ this Na-Al battery to form an acidic chloroaluminate catholyte, NaAl2Cl7. Leveraging the reaction between NaAlCl4 and NaAl2Cl7 in conjunction with that between Al/NaCl and NaAlCl4 advantageously utilizes the majority of Na available in the cathode for capacity, in addition to providing a higher discharge voltage (~ 2 V compared to ~ 1.6 V for the NaAlCl4 reaction), thereby adding ~ 119 Wh kg-1 additional specific energy, on top of the 493 Wh kg-1 theoretical specific energy of the neutral Na-Al battery reaction between Al/NaCl and NaAlCl4.Fundamental aspects of the acidic chloroaluminate reaction are investigated, showing that cells using only the acidic reaction are able to cycle for hundreds of cycles. The acidic reaction between NaAlCl4 and NaAl2Cl7 occurs via a solution-phase reaction, unlike the two-phase neutral reaction between NaCl/Al and NaAlCl4, and we confirm via Raman and NMR spectroscopies that complete conversion to NaAl2Cl7 occurs at end of charge. Na-Al batteries utilizing both reactions demonstrate high areal capacity (~ 46 mAh cm-2) and excellent reversibility. Enabled by the rapid mass transfer and solid-liquid reaction mechanism of the chloroaluminate catholyte, a higher areal capacity cell with ~ 132 mAh cm-2 is demonstrated, allowing a discharge duration of 28.2 h, implying that this Na-Al battery chemistry may be suitable for long-duration energy storage for grid applications. Finally, the raw active materials cost of this battery is estimated to be only ~ $7 kWh-1, which is promising for enabling low-cost renewable power utilization for the grid. Figure 1

Cathode stripping behavior: Simulation by the finite element method and experimental effect of cathode surface roughness and its repeated use

In order to increase productivity and reduce operating costs, a moderate adhesion between the electroplated metal and the mother blank is required. In this study, the influence of deposit thickness and adhesion strength on the stripping behavior of zinc deposits was investigated using finite element analysis (FEA), while the effect of cathode surface roughness and repeated use of the cathode (i.e., without intermediate brushing between plating cycles) was measured experimentally. The results showed that the aluminum cathode roughness increased with the number of plating cycles. The adhesion strength increased as the cathode roughness increased. Increasing the number of plating cycles also increased the amount of residual zinc particles on the aluminum surface. The FEA significantly improved the understanding of the stripping behavior. This analysis considered the adhesion, bending, and friction forces involved in the operation in relation to the stripping force. The bending force, which was found to be proportional to the variation in deposit thickness, represents the major component of the stripping force. Adhesion strengths have been shown to be responsible for the bend angle and consequently the amount of deposit deformation after stripping. The results of this study contribute to current knowledge and the implementation of operating conditions and routines that maximize productivity and reduce operating costs by reducing zinc sticking.

Effects of F− ions on the electrochemical and interface behavior of cathodes in zinc electrowinning

The increasing use of Zn metal in the energy and industrial sectors necessitates a higher level of research into the zinc electrowinning process. In this work, the effects of fluoride ions (F−) in zinc electrolyte on the cathodic kinetics and zinc product quality during zinc electrodeposition was systematically investigated via a series analysis. The results revealed that the addition of F− in the electrolyte showed a polarization effect, with an increase in the apparent cathodic exchange current density increased by 104 orders of magnitude, and a decrease in the zinc deposition overpotential by 46 mV at a concentration of 400 mg/L. However, F− also reduces the hydrogen evolution overvoltage, when the electrolyte contains 400 mg/L F−, the hydrogen evolution overvoltage on aluminum cathode and zinc cathode decreases by 121 mV and 97 mV, respectively. The promoted hydrogen evolution kinetics increases energy consumption and surface porosity. Additionally, F− ions corrode the Al2O3 oxide film on the cathode surface, accelerating the corrosion of the aluminum cathode plate. This results in increased adhesion of zinc deposition to the damaged aluminum substrate, making it difficult to peel off.

Non-contact gaseous microplasma electrode as anode for electrodeposition of metal and metal alloy in molten salt

Microplasma based on glow discharge could act as a non-contact gaseous electrode and has attracted much attention in both fundamental research and application. Herein, with microplasma as the anode, the electrodeposition process of a series of metal and metal alloys in molten salt has been systemically studied. Four metal cations with different valence states, silver (Ag+), nickel (Ni2+), copper (Cu2+), and iron (Fe3+), could all be reduced on the solid cathode with high current efficiency and the corresponding metal products were of high purity. The electrodeposition of aluminum-lanthanum (Al-Ln) alloy on the aluminum cathode was also successfully carried out with microplasma as the anode, and the same alloy was obtained by using the conventional anode electrode. These results indicated that microplasma anode based on non-contact direct-current (DC) glow discharge is a promising electrode to be applied in molten salt electrolysis.

Electrocoagulation treatment of compost leachate using aluminium alloy, carbon steel and zinc anode

Analysis of surface changes and corrosion occurrence at the electrode surface, electro-generated sludge analysis, and electrocoagulation (EC) treatment efficiency using aluminium alloy, low carbon steel, and zinc sacrificial anode as electrodes for the treatment of compost leachate with the medium organic load were compared for the first time. Different operating conditions (initial pH values in the range of 4–8, stirring rates in the range 70–270 rpm, and contact times in the range of 10–30 min) were used to study the EC process. Light microscopy analysis show the significant corrosion of anodes, while minor corrosion damage was also observed on the cathodes. Pitting was found on carbon steel and aluminium electrodes, and general corrosion on the zinc electrodes, which increase with the duration of EC (10 to 30 min). Weight loss analysis of electrodes shows a decrease in anode mass in all experiments and aluminium cathode mass, while steel cathode mass increases. Zinc cathode mass increases in initially acid and decreases in an alkaline environment. The highest anode consumption was obtained in the experiment with the Zn electrode (in the range of 0.3300–0.6469 g). SEM/EDS analysis of the electro-generated sludge confirmed the presence of aluminium, zinc, and iron, with oxygen as the main elements, while carbon indicated collected organic matter from the compost leachate. PXRD analysis of sludge shows a mixture of amorphous phase with the a semicrystalline phase of AlO(OH) and the crystalline phase of AlPO4 obtained with Al electrodes, an amorphous structure of the sludge obtained with Fe electrodes, and structurally well-ordered phases of Zn7Cu(OH)13((SiO(OH)3)0.7(O4H7)0.3(SO4)) and (Zn0.9Cu0.1)O obtained with Zn electrodes. In addition, the treatment efficiency was analysed and Taguchi's L9 orthogonal array design was performed.

Timing resistive plate chambers for thermal neutron detection with 3D position sensitivity

An optimized design of a neutron detector based on timing RPCs (Resistive Plate Chambers) with boron-10 neutron converters is presented. The detector is composed of a stack of ten double gap RPCs with aluminium cathode plates coated on both sides with 10B4C. This design enables simultaneous determination with high accuracy of both the neutron time-of-flight (down to ns resolution) and the interaction position in 3D (down to 0.25 mm resolution across and ∼1 mm along the beam). It is shown that the detection efficiency can approach 60% for neutrons with lambda = 4.7 Å. A new geometry with less material budget is introduced for the signal pick-up strip arrays. The results of simulation-based optimization of the design are reported considering the trade-off between the detection efficiency, the count rate capability and the amount of elastic scattering on the detector components.

Decolorisation of Reactive Congo Red Dye Solution by Electro Coagulation Process

The decolourisation of the reactive Congo red dye from synthetic wastewater was studied using ElectroCoagulation (EC) technique. In an effort to increase removal efficiency, the effects of operating parameters including flow, inter electrode distance, conductivity, voltage, and Hydraulic Detention Time (HDT) were investigated. An electrochemical cell was initially created with an aluminum cathode and anode. Following that, each variable's impact was examined independently using synthetic wastewater. The colour removal efficiency was 93% when the initial dye concentration was 4 mg/L, the conductivity was 300 ppm, the temperature was 24 oC, the interelectrode spacing was 1 cm, and the HDT of the electrolysis was 120 min.

Modification of Child-Langmuir Law for Electrodes of Different Materials and Shapes Using Nitrogen Gas

A dc glow discharge plasma between the planar electrode and planar, conical, and hemispherical electrodes was studied. The electrode materials made of aluminum, graphite, and stainless steel (SS) were used. The experimental results showed a deviation in the traditional Child-Langmuir (CL) law as a result of the use of different shapes and materials of anodes and cathodes. The new parameters of the modified CL law as a function in the surface areas of electrodes, their work function materials, and their contributions to the electrical discharge. The lowest discharge characteristics were for the aluminum planar electrode (anode or cathode) with the aluminum and graphite hemispherical one. The planar aluminum cathode with the conical SS anode gave the highest discharge characteristics. The planar aluminum anode with conical SS cathode had the lowest Paschen curve values. In Paschen curves, the highest values were discovered to be for the planar cathode in a comparison with different cathodes. The hemispherical aluminum anode had the highest Paschen values compared with different anodes. Moreover, the contribution ratio of the anode to the cathode in the discharge for the aluminum planar diode was equal to the ratio between their surface areas and the ratio between their work function materials. In contrast, this contribution ratio for the other discharge cases was equal to the multiplication of the surface areas ratio of the anode to cathode and the ratio of their materials’ work functions. The modified CL law and its coefficient were generalized for the electrodes of different shapes, materials, and used gases.