Electrochemical Performance of LiMn2O4 Cathodes in Zn-Containing Aqueous Electrolytes

Influence of different electrolysis parameters on electrodeposition of γ- and α-Mn from pure electrolytes — a review with special reference to Russian language literature

Electroextraction of zinc from sulphate electrolytes containing antimony ions and hydroxyethylated-butyne-2-diol-1,4: Part 3. The influence of manganese ions and a divided cell

Removal of Cl([sbnd]I) from zinc sulfate electrolyte by the porous Bi2O3 rich in OVs: Efficiency and mechanism

The dominant role of Mn2+ additive on the electrochemical reaction in ZnMn2O4 cathode for aqueous zinc-ion batteries

Anion influence in lead removal from aqueous solution by deposition onto a vitreous carbon electrode

Electrodeposition of Ni-zirconia or Ni-titania composite coatings from a methanesulfonic acid bath

Introduction. Oxidation of titanium implants is used to impart biological compatibility properties to the surface and to mark for medical products. Artificially formed oxide films have a certain thickness and uniformity of chemical composition. Electrochemical oxidation allows to obtain films of a given thickness on products of any configuration, using simple equipment. The properties of oxide coatings, namely, the thickness and structure of the oxide layer, are determined by the type of oxidation electrolyte and the mode of oxidation of the alloy. The aim of the work is to study the effect of the process mode on the electrochemical oxidation of the Ti6Al4V alloy in sulphate electrolytes. Materials and research methods. The dynamics of the formation of oxide films in a sulfate electrolyte were investigated by analyzing the forming dependences U = f (τ) obtained by oxidizing the material in galvanostatic mode using a sequential circuit with a B5-47 power source and a Keithley-2000 multimeter. Results. The nature of the molding dependencies of the alloy depends on the density of the oxidation current. At j a 0.5 A·dm –2 , interference-colored oxide films are formed on the alloy surface. The maximum film thickness is determined by a given voltage value and does not depend on other parameters of electrolysis. For a number of identical voltage values, the dependence of the electrolysis duration on the current density is linear, which indicates the formation of low-porous films. The color of the oxide film is determined by the voltage value and does not depend on the current density and electrolyte concentration. The correspondence of the color of the film and the voltage in the range of its values of 10-100 V. The analysis of formation dependences has made it possible to establish that when oxidation of the alloy in sulfate electrolytes, low porous oxide films are formed.

Aqueous rechargeable batteries are regarded as one of the most reliable solutions for electrochemical energy storage, and ion (e.g., H+ or OH-) transport is essential for their electrochemical performance. However, modeling and numerical simulations often fall short of depicting the actual ion transport characteristics due to deviations in model assumptions from reality. Experimental methods, including laser interferometry, Raman, and nuclear magnetic resonance imaging, are limited by the complexity of the system and the restricted detection of ions, making it difficult to detect specific ions such as H+ and OH-. Herein, in situ visualization of ion transport is achieved by innovatively introducing laser scanning confocal microscopy. Taking neutral Zn-air batteries as an example and using a pH-sensitive probe, real-time dynamic pH changes associated with ion transport processes are observed during battery operation. The results show that after immersion in the zinc sulfate electrolyte, the pH near the Zn electrode changes significantly and pulsation occurs, which demonstrates the intense self-corrosion hydrogen evolution reaction and the periodic change in the reaction intensity. In contrast, the change in the pH of the galvanized electrode plate is weak, proving its significant corrosion inhibition effect. For the air electrode, the heterogeneity of ion transport during the discharging and charging process is presented. With an increase of the current density, the ion transport characteristics gradually evolve from diffusion dominance to convection-diffusion codominance, revealing the importance of convection in the ion transport process inside batteries. This method opens up a new approach of studying ion transport inside batteries, guiding the design for performance enhancement.

The effect of varying concentrations of Al3+ on the morphology and current efficiency of electrodeposited nickel from an acid-sulfate electrolyte was studied. Concentrations of Al3+ of 20 to 100 ppm significantly degraded the nickel-cathode morphology and current efficiency. However, it was found that higher concentrations of Al3+, in the range of 1 to 5 g/L, depending on the electrolyte parameters and operating conditions, improved the deposit morphology compared to deposition from a pure electrolyte. However, the current efficiency remained low. Physical characterization of the nickel revealed that a smoother, more uniform surface resulted from deposition in the presence of 1 g/L or greater of Al3+. Impedance analysis indicated the presence of an inhibiting layer on the cathode when low concentrations of Al3+ were present. Concentrations of Al3+ greater than 1 g/L appeared to modify this layer and the nickel-deposition mechanism, allowing improved nickel morphology and structure.

The influence on specific discharge characteristics of redox - active iodide and bromide electrolytes of polyaniline as the cathode material in electrochemical energy sources with zinc anode was studied. Electrochemical and capacitive properties of PAN cathode was investigated using galvanostatic, potentiostatic, cyclic voltampermetric and impedance methods. It was established that PAN cathode inherent discharge specific capacity of Ср = 126 A × h × kg-1 with current load і = 103 A × kg-1 in zinc - sulfate electrolyte and Ср = 301 A × h × kg-1 in the same conditions in the presence of KI. Thus there is a reverse transition of various forms of PAN leucoemeraldine / emeraldine, that among the redox electrolyte causes increase in electrical capacitance and conductivity of PAN electrodes in the charged state.

Electrodeposition of Ni[sbnd]Co alloy from methansulfonate electrolyte. The role of the electrolyte pH in the anomalous codeposition of nickel and cobalt

Removal of toxic cadmium (II) from zinc sulfate solution with zinc powder enhanced by ultrasound: Kinetics and mechanism

The presence of excessive lead in zinc sulfate electrolytes can lead to problems related to both processing efficiency and the properties of the metal produced. For example, poor adhesion can occur in electrogalvanized steel when it is heated in the temperature range of 215 °C to 280 °C if lead is present in the deposit. The duration of heating necessary to induce the peeling of the zinc was found to be dependent on the temperature, time, and concentration of lead in the electrolyte and the plating parameters. The presence of lead slowed the formation of the intermetallic, and the peeling occurred between the zinc and the iron-zinc intermetallic layer. In order to gain a better fundamental understanding of the role of lead, rotating disc electrodes were used to measure the diffusion coefficient of lead in the zinc sulfate electrolyte. The experimentally determined mass transport data on lead can be used as an aid to set an acceptable limit of lead allowable in the electrolyte or to evaluate the electrochemical characteristics of an electrolytic zinc system. By the addition of strontium carbonate to the plating solution followed by filtration, the lead concentration in the electrolyte could be reduced to an acceptable level, preventing the poor adhesion on heating.

In this study, a low-cost and friendly compound diazolidinylurea carrying a number of heteroatoms and inter/intra hydrogen bonding, a derivative of urea (DU), efficiently strengthened aqueous zinc ions batteries (AZIBs) in ZnSO4 electrolyte. The influence of DU on the zinc anode in the 2 M ZnSO4 electrolyte was fully studied by various surface chemistry and electrochemistry means. It is demonstrated that the super low concentration of DU (2 mM, 0.00556 wt %) could inhibit the formation of zinc dendrites, zinc corrosion, and the hydrogen evolution reaction during the constant current cycling of water system ZIBs, which thus enabled symmetric zinc-zinc batteries to reach a cycle life of 7336 h (nearly 306 days) under 1 mA·cm-2, 1 mA h·cm-2 at 25 °C and 426 h (nearly 18 days) at 55 °C, and inspired zinc-manganese full battery to maintain a capacity retention rate of more than 52% after cycling for 1000 cycles under a current of 2 A·g-1. These results are much superior over zinc ion cells based on the blank ZnSO4 batteries. Even if the Zn-Cu half cells including the DU/2 M ZnSO4 electrolyte were also more pronounced than those with the bare ZnSO4 electrolyte. The maximum corrosion inhibition efficiency of the DU for the zinc electrode in ZnSO4 solution exceeded 82%. Hence, the suppression of zinc corrosion and parasitic side reactions, as well as the formation and growth of zinc dendritic crystals by the addition of DU in zinc sulfate electrolyte, played a central role in intensifying aqueous zinc ion batteries.

The impact mechanism of Mn2+ ions on oxygen evolution reaction in zinc sulfate electrolyte