Aluminum Anode Research Articles

Operando odd random phase electrochemical impedance spectroscopy for in situ monitoring of the anodizing process

Electrochemical impedance spectroscopy (EIS) is a versatile technique to characterize electrochemical systems satisfying causality, linearity and stationarity requirements. Odd Random Phase multisine EIS (ORP-EIS) can measure time-varying impedances for non-stationary processes. In this work, operando ORP-EIS is introduced to monitor the anodizing of aluminum, which is a nonlinear and non-stationary process, by superimposing a multisine AC perturbation signal on the anodizing DC potential. Results show that the multisine signal does not disturb the growth of the oxide film. Moreover, this technique makes it possible to follow the growth of the barrier oxide layer and provides an opportunity to investigate processes like ion adsorption, ion incorporation and ion movements through the oxide layer during anodizing. These processes cannot be studied by conventional EIS.

Anodizing of aluminum 6061 alloy with incorporated nanoparticles to inhibits the aluminum corrosion

In this work, Aluminum alloy 6061 (A6061) was modified by Anodizing and incorporating with ZnO and Fe3O4 nanoparticles to improve its corrosion-resistant. The titanium sheet was used as a counter electrode and the DC voltage reach 20 mV while the anodizing solution was 20% H2SO4 while the H2SO4 was mixed with the two Oxide nanoparticle to incorporate the AA6061 surface. Anodizing and incorporation with (ZnO and Fe3O4) NPS were confirmed by X-ray diffraction. The surface morphology of anodized and incorporated surface was examined through scanning electron microscopy (SEM). Modified A6061 by Anodizing and nanoparticle incorporation revealed a good corrosion protection efficiency even at temperatures ranging (298-328) K in a saline medium. Where the corrosion current density increase with the increase in temperature. Activation energy and pre-exponential factor (kinetic parameters) were calculated and discussed. Also, thermodynamic values ?G* and ?H* were calculated.

Fabrication of Zirconium Silicate Reinforced Superhydrophobic Coating for the Evaluation of Corrosion-Resistance.

The present work investigates on anodisation of aluminium in 1.0 M sodium oxalate and methodically evaluates the influence of zirconium silicate as an additive. The effect of additive upon structure, morphology, micro hardness and composition of the coating formed under various anodising conditions has been examined comprehensively. The surface of the coating was modified by stearic acid and its immersion time was optimized. The dependence of surface morphology, kinetic parameters, and microstructural characteristics of the coating on electrolyte /additive concentration, anodising time, and the temperature has also been inspected. X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) combined with EDAX studies indicates the beneficial role of zirconium silicate towards the formation of crystalline coating with improved corrosion-resistant characteristics. The static water contact angle on the surface-modified coatings was 122° ± 0.4°. This contact angle of super hydrophobic coating has been improved by KOH treatment (152.76o ± 0.4°) which is obtained under optimized conditions exhibit the corrosion resistance (1.68 × 108 Ω cm-1)which is nearly 8 times higher than that of bare aluminium (8.36 × 101 Ω cm-1). The efficacies of the surface-modified coatings against bacteria that are commonly encountered in marine (Desulfovibrio desulfuricans) and medical applications (Staphylococcus aureus and Escherichia coli) are also demonstrated.

Bifunctional TiN@N-doped-graphene catalyst based high sulfur content cathode for reversible Aluminum-Sulfur batteries

Aluminum-sulfur (Al-S) batteries are drawing extensive attentions for the development of economical battery systems owing to the high theoretical capacity of 1672 mAh g−1 and low-cost naturally abundant electrode materials, Al and S. However, Al-S batteries are beset by poor reversibility and low actual capacity, only few reversible Al-S cells have been reported until now. In this work, factors affecting Al–S batteries performance are explored and explained, such as the inactive discharge product(Al2S3), polysulfides diffusion and the self-discharge reaction on the surface of SEI-layer-free aluminum anode. And we demonstrate an improved Al–S battery by effectively adjust the voltage window and develop TiN@N-doped-graphene catalyst materials to modify the sulfur cathode. This catalyst is for the first time applied in Al–S batteries and explored its positive effects during the reversible Al-S reactions. Comprehensive electrochemical testing and ex-situ characterization certificates that, in the discharging process, the shuttle effect of polysulfides is suppressed based on the strong adsorption of catalyst; in the charging process, sulfide redox kinetics are promoted and the decomposition reaction barrier is reduced by the catalyst. The Al-S cell delivers an initial capacity of ∼993 mAh g−1 and maintains a capacity of ∼500 mAh g−1 after 200 cycles.

Local Anodizing of a Newly Prepared Aluminum Micrometric Disk.

A search through the literature reveals that the vast majority of studies about aluminum anodizing were conducted at the macroscale (i.e., from cm2 up to m2), while those focused on local anodizing (i.e., on surfaces of less than 1 mm2) are rare. The last ones either used insulating masks or were conducted in an electrolyte droplet. The present study describes on the one hand a new way to prepare aluminum microelectrodes of conventional disk-shaped geometry, and on the other hand the local anodizing of their respective aluminum micrometric top-disks. The influence of the anodizing voltage on anodic film characteristics (i.e., thickness, growth rate and expansion factor) was studied during local anodizing. Compared with the values reported for macroscopic anodizing, the pore diameter appears to be significantly low and the film growth rate can reach atypically high values, both specificities probably resulting from a very limited increase in the temperature on the aluminum surface during anodizing.

Effect of Cerium Chloride on the Self-Corrosion and Discharge Activity of Aluminum Anode in Alkaline Aluminum-air Batteries

One of the key impediments to aluminum (Al) as an anode in alkaline Al-air batteries is self-corrosion, which limits the battery’s efficiency due to the capacity loss and lifespan reduction. Thus, it is vital to find an efficient electrolyte additive that reduces self-corrosion in Al anodes. In this study, the effect of adding 0.5 to 1.5 wt% of cerium chloride to 4 mol l−1 KOH electrolyte on the self-corrosion of pure Al anode was investigated using electrochemical experiments. The results show that the addition of cerium chloride to the electrolyte reduces self-corrosion of the Al anode with a negligible effect on the anode activity. Cerium chloride forms cerium hydroxide (Ce (OH)3) in the alkaline electrolyte, which is adsorbed on the Al surface. Therefore, the corrosion potential increased, and self-corrosion current density decreased. As the cerium chloride concentration increased, the Al anode efficiency increased from 43.8% to 76.1%, and the capacity density increased from 1294 to 2244 mAh g−1. Furthermore, increasing the immersion time of the Al anode in the electrolyte containing cerium chloride increased the self-corrosion resistance and provided the self-healing properties for the anode.

Electrochemical Performance of Al-1Zn-0.1In-0.1Sn-0.5Mg-xMn (x = 0, 0.1, 0.2, 0.3) Alloys Used as the Anode of an Al-Air Battery

In this work, Al-1Zn-0.1In-0.1Sn-0.5Mg-xMn (x = 0, 0.1, 0.2, 0.3) alloys are prepared and used as the anode of an Al-air battery (AAB). We use scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) and optical microscopy (OM) to analyze the microstructures of the alloys. The hydrogen evolution rate, electrochemical performance (including polarization curves), electrochemical impedance spectroscopy (EIS), and battery performance of the samples are examined in the 4 M NaOH electrolyte. The experimental data display that the average grain size is significantly refined after adding manganese into the Al-1Zn-0.1In-0.1Sn-0.5Mg alloy, with a decrease in grain size from over 100 μm to about 10 μm. The improved activity of the aluminum anode in the AAB can be attributed to the introduction of manganese. The Al-1Zn-0.1In-0.1Sn-0.5Mg-0.1Mn alloy possesses the optimal overall performance with a lower self-corrosion rate (0.128 mL∙cm−2∙min−1), the highest working potential (1.630 V) and energy density (2415 mWh·g−1), a higher capacity (1481 mAh·g−1) and anodic utilization (49.75%).

Tuning intrinsic photoluminescence from light-emitting multispectral nanoporous anodic alumina photonic crystals

To control and harness the intrinsic photoluminescence of solid-state, light-emitting materials produced by self-organization approaches remain challenging. This study demonstrates how the intrinsic broadband photoluminescence emission from nanoporous anodic alumina (NAA) produced by anodization of aluminum in oxalic acid electrolyte can be precisely tuned by engineering its structure in the form of photonic crystals (PCs). A combination of pulse and constant anodization in distinct acid electrolytes makes it possible to engineer a novel heterogeneous optical structure consisting of two layers: (i) a non-emitting, light-filtering layer in the form of multi-spectral nanoporous anodic alumina photonic crystals (MS–NAA–PCs) on its top (i.e., 58 µm thick and average pore diameter of 17 nm) and (ii) an intrinsically light-emitting layer of NAA at its bottom (i.e., 50 µm thick an average pore diameter of 40 nm). MS–NAA–PCs are engineered to feature three intense, well-resolved photonic stopbands (PSBs), the positions of which are spaced at specific regions of the visible spectrum from ∼380 to 560 nm. It is demonstrated that the PSBs of the non-emitting MS–NAA–PCs on top of the heterogeneous optical structure act as a light-filtering component, which makes it possible to narrow and tune the characteristically broad, Gaussian-like photoluminescence emission from the underlying light-emitting NAA layer. This structural design makes it possible to narrow the width of photoluminescence emission up to ∼50 nm and blue shift its position for ∼15 nm. Our advances pave the way for novel designs of intrinsic, light-emitting NAA-based PC structures, which could find broad applicability across light technologies, such as sensing and biosensing, photodetection, and solar light harvesting.

Effect of carbon addition on dissolution behavior of aluminum alloy sacrificial anode

Using potentiodynamic polarization and immersion corrosion and sacrificial anode material discharge performance testing methods studied the dissolution behavior of aluminum anode material in the working condition of simulated Northwest oilfield corrosion conditions. The research results show that carbon can reduce the corrosion potential of aluminum anode material and anode current density increase, which can improve the material corrosion dissolution performance. Immersion corrosion test results show that with the carbon content in ascension, to enhance the anode material of aluminum anode material of uniform dissolving ability, passivation phenomenon was significantly suppressed. Adding carbon anode materials to add up the uniform’s ability to dissolve, eliminate the phenomenon of local corrosion of anode material and the discharge efficiency is greatly increased, effectively solve the aluminum anode material in high temperature environment to serve the current efficiency degradation of field engineering problems.

Effect of Crystal Orientation on the Corrosion Behavior of As-Cast Pure Aluminum Anodes in Air Batteries

Effect of Crystal Orientation on the Corrosion Behavior of As-Cast Pure Aluminum Anodes in Air Batteries

Metallurgical investigation of aluminum anode behavior in water-in-salt electrolyte for aqueous aluminum batteries

Although ionic liquid electrolytes (ILs) are environmentally unfriendly, they are the most common electrolyte used in aluminum-ion batteries (AIB). Aqueous electrolytes offer a more sustainable alternative, but problem with oxide passivating barrier on Al surface becomes more profound. Recently, a new sub-class of aqueous electrolytes, water-in-salt (WIS) of (AlCl3·6H2O), has been considered, but experimental validation of the behavior of the Al electrode over cycling is required. This work investigates aluminum/graphitic cells using WIS electrolytes with a mass ratio of salt to water of 4, 8, and 12 and finds that they show similar trends in cycling performance. The degradation observed over cycling has been attributed to the formation of a detrimental solid electrolyte interphase (SEI) layer on the Al surface. It was found that WIS 4 increased Al corrosion, resulting in a slightly higher capacity and longer cycling life. Metallurgical observation showed that the Al matrix has a tendency to initiate corrosion around Al3Fe intermetallic phases in both WIS and ILs. This implies that the presence of Al3Fe particles allows the electrolyte to break the oxide barrier and access the bulk Al. These results suggests that metallurgical treatments are important to enhance the electrochemical performance of AIB.

Progress and Trends in Nonaqueous Rechargeable Aluminum Batteries

AbstractIt is important to research new energy storage technology for substituting the deficiencies of current energy storage devices, i.e., the poor energy density of lead‐acid batteries, the high cost of lithium‐ion batteries, etc. Rechargeable aluminum batteries (RABs) are regarded as one of the most promising storage devices due to the abundance of the materials required, superior security, and decent energy density of aluminum anodes. Nevertheless, there are some significant challenges, such as the developing energy density of cathodes, corrosion, and the high cost of electrolytes, which set obstacles to the industrialization of RABs. For avoiding the pitfalls of RABs research and boosting the development of RABs, the recent progress and trends in RABs covering mechanisms, components of RABs (electrodes, electrolytes, separators, and current collectors) and technology of assembly and packaging of devices are summarized and proposed.

Optimal performance of electrodialysis process for the recovery of acid wastes in wastewater: Practicing circular economy in aluminum finishing industry

This work aimed to apply electrodialysis (ED) for the recovery of diluted sulfuric acid (H2SO4) waste liquor generated at rinsing baths in the aluminum anodizing industry. A bench-scale ED process was used to recover acid and water from diluted waste acid liquors in the aluminum anodizing process. The optimal conditions and parameters defined in bench-scale studies were utilized to treat a real industrial acid solution. A bench-scale ED system was run continuously with a connected rinse water line of aluminum plating to concentrate diluted sulfuric acid for recovery. Industrial-scale studies confirmed that the produced concentrated acid and water solutions were of sufficient quality to be reused during the aluminum anodizing process. Besides, diluate characteristics allowed it to be reused as rinse water and reduced the effluent volume sent to the wastewater treatment plant by 90%. Electrodialysis treatment provided a near-zero pollutant discharge. Closed cycle water and acid usage loop were achieved for the aluminum galvanic process, which lessens the environmental and economic impacts of the process. Overall, electrodialysis presented a promising option for the aluminum industry.

On the Nature of Self-Organization of Porosity During Aluminum Anodization

On the Nature of Self-Organization of Porosity During Aluminum Anodization

Trend Removal in Measurements of Best Linear Time-Varying Approximations—With Application to Operando Electrochemical Impedance Spectroscopy

Equilibria evolving over time, also called trends, are often present in ongoing measurements of real-life systems. These trends are considered as disturbances when computing the best linear time-varying approximation (BLTVA) of the system. Current techniques for dealing with trends in BLTVA measurements consist of modeling the trend with a finite number of basis functions. However, in measurements with dominant trends, the trend cannot always be captured well enough by this set of basis functions, and hence, the uncertainty on the BLTVA increases. As a consequence, one loses low-frequency information. In this article, the state-of-the-art method for estimating the BLTVA is extended by removing the trend with a differencing operator. It is shown that with this novel technique, low-frequency information becomes more visible. Moreover, the novel method decreases the variance on the BLTVA and allows to measure fewer periods. Hence, the novel technique improves the route for treating arbitrary out-of-equilibrium or also called operando, measurements. As an illustration, it is applied to operando time-varying impedance measurements of three electrochemical processes: the charging of a Li-ion battery cell, the electrorefining of copper, and the anodizing of aluminum.

Regulating solvation and interface chemistry to inhibit corrosion of the aluminum anode in aluminum–air batteries

Introducing sodium stannate and potassium acetate in an alkaline electrolyte as a hybrid high concentration electrolyte for aluminum–air batteries.

Contribution of constitutional liquation of the segregation phase to improve the electrochemical performance of Al–Sn based anodes

A liquid segregation phase was constructed in an aluminum anode to improve the electrochemical performance of Al–air batteries.

ELEKTROKOAGÜLASYON İLE SU ARITMA

Electrochemistry is the science that study, the effect of the electricity on the phase of matter by producing chemical reactions, which causes this effect. Several applications and technologies such as; batteries, fuel cells, and industries, such as aluminum industry depend on theories of electrochemistry science. Integration of electrochemistry with other chemistry science such as; environmental chemistry, contributes highly in serving environment to be clean, and safe. One of electrochemistry applications in waste water treatment is the electrocoagulation; which considered as; one of the best water treatment methods. This technology depends on electrolysis of aluminum or steel anode, to produce ions, can be react with water ions, and producing new complex polymeric compounds that will flocculate the suspended particles, and deposit it in the bottom of electrocoagulation tank. Using this technology, takes avital role in cancelling the need of coagulation chemicals, and thickeners, beside that the level of electrical current that used is low. But some limits still exist; such as; the regular need to replace the anodic electrode, because it dissolves in water, electricity may be expensive in some places.

Chrysanthemum coronarium leaves extract as an eco-friendly corrosion inhibitor for aluminum anode in aluminum-air battery

In this study, the effect of chrysanthemum coronarium leaves extract (CCLE) in increasing alkaline aluminum-air (Al-air) battery performance is elucidated using hydrogen gas evolution tests, various electrochemical measurements and battery performance tests. CCLE additive displays the outstanding corrosion inhibition effect on the Al anode through the formation of a protective film on the Al surface. The surface morphology of Al is assessed by scanning electron-microscopy (SEM), and atomic force microscopy (AFM). Fourier transform infrared (FT-IR) spectroscopy, and x-ray photoelectron spectroscopy (XPS) are applied to disclose the chemical composition of the extract as well as formation mechanism of the protective film on the Al surface. This film is caused by the electrostatic interactions, hydro-bonds and/or a combination of these between the extract molecules and aluminum surface. The presence of this film advances the capacity density of battery up to 2941.18 mAh g -1, increases three fold compared to a 4 M NaOH solution. Also, the electrochemical activity of the Al electrode is improved significantly.

AC Corrosion behaviour of aluminium and zinc sacrificial anodes in seawater

ABSTRACT In this work, the corrosion behaviour of aluminium (Al) and zinc (Zn) sacrificial anodes under AC interference were studied in 3.5% NaCl solution by AC corrosion simulation experiments, weight loss tests and surface morphology analyses. It was found that AC accelerated the corrosion of Al and Zn, and their corrosion rates increased with the AC current density, besides the localised corrosion of Al was much more obvious than Zn. When the AC current density was 100 A m−2, the uniform corrosion rates of Al and Zn increased to 14.6 and 0.46 mm/year, respectively, which were 34.8 and 1.48 times of the free-corrosion rates of them. Meanwhile, both the uniform and localised corrosion rates of Al increased much more significant than that of Zn under AC interference.