Russian Journal of Electrochemistry最新文献

The traditional graphite electrode materials can’t meet the needs of the Li-ion batteries with high energy density because of its low specific capacity, it is of great practical significance to modify the traditional graphite electrode materials and improve their specific capacity. In this paper, a simple one-step method is used to recombine silicon onto the conventional graphite electrode materials, which greatly improves the specific capacity and the cycling performance of the electrode materials. When the content of silicon in the carbon–silicon (C/Si) composites is 10.5 wt %, the theoretical specific capacity of the obtained C/Si composites is 692.7 mA h/g, and after 1000 cycles of charge and discharge, the actual specific capacity is 580 mA h/g, which is about 81.8% of the theoretical specific capacity; when the content of silicon in the C/Si composites is 32.7 wt %, the theoretical specific capacity of the obtained C/Si composites is 1420.7 mA h/g, and after 1000 cycles of charge and discharge, the actual specific capacity can still reach 1050 mA h/g, which is about 73.9% of the theoretical specific capacity; when the content of silicon in the C/Si composites is 48.6 wt %, the theoretical specific capacity of the obtained C/Si composites is 1930.6 mA h/g, and after 1000 cycles of charge and discharge, the actual specific capacity is 745 mA h/g, which is about 38.6% of the theoretical specific capacity; therefore, the optimal content of silicon in C/Si composites is about 32.7 wt % in terms of battery performance and production costs. Through incorporating silicon into traditional graphite electrode materials via thermal decomposition of silane, the specific capacity of the negative electrode is improved significantly, which is a better way to upgrade the products of the traditional graphite negative electrode materials manufacturers.

A corrosion behavior of an intermetallic compound and solid solutions based on the Co75Me25 two-component systems, where Me = Si, Fe, Cr, is considered. The surface morphology of the samples is analyzed using electron and optical microscopy. Corrosion is studied using the polarization-curve method and electrochemical impedance spectroscopy. The greatest corrosion resistance is shown to be achieved in the Co–Cr sample due to the presence of chromium alloying additive, an inhibitory component. Results of corrosion tests for the catalytic capabilities of two-component alloys is discussed briefly. This study also made it possible to explain the role of the intermetallic compound Co₂Si in terms of corrosion behavior of an active electrode-catalyst in the nitrate electrochemical reduction reaction.

The gas diffusion layer (GDL) is a critical component of proton exchange membrane fuel cells (PEMFCs), playing a key role in mass transport, electrical conduction, and water management. In this study, accelerated stress testing (AST) was conducted to investigate the effects of operating potential, temperature, and potential of hydrogen (pH) value of electrolyte on carbon corrosion-induced degradation in the GDL. The results revealed that high potential conditions, particularly at 1.5 V vs. reversible hydrogen electrode (RHE), led to severe corrosion characterized by significant reductions in hydrophobicity (contact angle <125°) and increased in-plane resistivity (>40 mΩ cm). Additionally, the mechanical strength of the GDL exhibited a non-monotonic trend with pH, reaching a minimum at pH 3, which corresponds to the electrocapillary “zero charge potential.” Electrochemical performance deteriorated significantly when corroded GDLs were employed as cathodes, with a notable decrease in current density (1600 mA cm^–2 @ 0.46 V). This work systematically elucidates the degradation mechanisms of GDLs under various simulated PEMFC operating conditions and provides insights for improving GDL durability in practical fuel cell applications.

Electrocoagulation has turned out to be a versatile and sustainable remediation for wastewater alterations, with many advantages over established treatment techniques. This is an electrochemical process that complexes the principles of coagulation, flotation and precipitation to completely remove a variety of pollutants from various types of wastewaters. An electric current is applied to sacrificial iron or aluminum electrodes, whereby electrocoagulation causes the production of coagulants in situ, causing destabilization and aggregation of the inorganic and organic materials from the water. This method has been found to be promising in treating industrial effluent, municipal wastewater, and even emergent contaminants such as pharmaceuticals and personal care products. It is energy-efficient and requires only limited and less toxic chemicals and leads to deficient sludge generation, thereby making it an eco-friendly substitute to the conventional chemical coagulation methods. Besides, electro-coagulated systems are compact, easily automated and easily fit different scales of operation-right from small decentralized units to large treatment plants. Given the ever-escalating concern worldwide over water scarcity and pollution, electrocoagulation is one of the promising technologies for strengthened water management and environmental conservation.

The corrosion of low-carbon steel in 1 M HCl + 1 M H₃PO₄ solution containing Fe(III) salts is studied under conditions of natural and forced convection. In this environments, partial reactions of iron anodic ionization, H⁺ and Fe(III)-cation cathodic reduction on steel occur. The first two reactions pass under kinetic control; the last one is diffusion-controlled. A composition of 4.5 mM IFKhAN-92 + 0.5 mM KNCS + 200 mM urotropine is studied as a steel corrosion inhibitor in this environments. In the solutions under consideration, the three-component inhibitor slows down all partial reactions involving steel and, as a consequence, its corrosion, which is a result of the polymolecular protective layer formation on the metal surface. The empirical dependence of the steel corrosion rate on the flow intensity of such media is described by the linear equation k = k_st + λw^1/2, where k_st is the steel corrosion rate in a static medium, w is the rotation velocity of the propeller mixer creating the medium flow, λ is the empirical coefficient characterizing the rate of increase of steel corrosion increment. The presence of a three-component-inhibitor additive in acid solutions containing Fe(III) salts reduces the values of k_st and λ parameters significantly, indicating that it slows down the metal corrosion in both static and dynamic environments. The 1 M HCl + 1 M H₃PO₄ solution added with the studied three-component inhibiting composition is shown to be able using as a medium for cleaning low-carbon steel surfaces from mineral deposits, resistant to the Fe(III) salts’ accumulation.

The state-of-the-art in investigations in the field of cathode materials based on lithium–cobalt double phosphate for lithium-ion rechargeable batteries is surveyed. The specific features of the LiCoPO₄ crystal structure, the transfer rate of charge carriers, the main synthetic methods of preparation, and the electrochemical characteristics of LiCoPO₄-based cathodes such as discharge capacity, charge–discharge rate, and cyclability are considered. The electrochemical characteristics of lithium-ion batteries based on LiCoPO₄ can be considerably improved by using nanosized and composite materials, doping with different cations, and using electrolytes stable at high potentials. The average working potential of LiCoPO₄ is ~4.8 V vs. Li/Li⁺, the discharge capacity at 0.1 С approaches its theoretical value (167 mAh/g).

In marine and industrial environments, zinc-rich coatings based on cathodic protection properties are among the most widely used and recommended coatings for the protection of metal surfaces from corrosion. Nevertheless, there is a paucity of research examining the electrochemical characteristics of water-based inorganic zinc-rich coatings and solvent-based epoxy zinc-rich coatings. Therefore, this paper presents a comparative analysis of the electrochemical properties of a solvent-based epoxy zinc-rich coating and a water-based inorganic zinc-rich coating. The objective of this study was to systematically examine the anticorrosion properties of bothcoatings using the following methods: open circuit potential (OCP), low-frequency impedance modulus, and electrochemical impedance spectroscopy (EIS) curve. The experimental results demonstrated that both coatings offered effective cathodic protection to the metal substrate. Comparatively, the water-based inorganic zinc-rich coating displayed a superior cathodic protection effect, which is attributed to its loose and porous structure. The distribution of zinc powder during the coating preparation enhanced the filling of internal voids within the coating system, promoting electrical connectivity between the zinc powder and the metal substrate, as well as among the zinc particles themselves. This interaction increased the utilization efficiency of zinc powder within the coating, thereby improving its cathodic protection capabilities. These findings contribute to the theoretical understanding of the protective mechanisms of zinc-rich coatings.

In this study, carbon felt-supported PbO₂ (CF/PbO₂) anodes were modified via doping Ce, Bi and La. The incorporation of these metal dopants significantly refined the β-PbO₂ grain size, increased the oxygen evolution overpotential, and reduced the charge transfer resistance of CF/PbO₂ anodes. Among the modified anodes, the CF/La–PbO₂ anode exhibited superior electrocatalytic oxidation performance, achieving a p-nitrophenol (p-NP) degradation efficiency of exceeding 99% within 90 min of electrolysis. Even after 10 consecutive cycles, the CF/La–PbO₂ anode maintained excellent stability, with a p-NP efficiency over 96%. The results of quenching experiments and electrochemical characterizations revealed that the degradation behaviour of p-NP on the modified anodes was dominated by direct electron transfer, but not active species-mediated oxidation. Furthermore, GC–MS analysis identified several intermediates, and a plausible degradation pathway involving hydroxylation, ring cleavage, and mineralization was proposed. Overall, the incorporation of La, Ce, and Bi—particularly La—significantly enhanced both the electrocatalytic activity and stability of CF/PbO₂ anodes, showing their potential as promising anode material for treatment of organic pollutants.

Battery technology serves as the primary energy storage system in the modern world. The global market share of Li-ion batteries (LIBs) has rapidly increased due to the demand in day-to-day life, which has attracted the scientific community towards this research area. Polymer electrolytes (PEs) are a key component of LIBs, which are categorized into three types: solid polymer electrolytes (SPEs), gel polymer electrolytes (GPEs), and composite polymer electrolytes (CPEs). When these PEs are integrated into batteries with inorganic fillers, ionic liquid (IL), nanomaterials, and plasticizers, they enhance the electrochemical stability window, ionic conductivity, transport number, and mechanical robustness of PEs. The choice of PEs in batteries depends on the selection criteria of polymer host types, such as PEO, PVDF, PVA, PMMA, PVP, PAN, and chitosan, as well as metal salts, including LiClO₄, LiTFSI, LiPF₆, LiBF₄, and LiBOB, are discussed. This review presents a detailed study of SPEs, GPEs, and CPEs, examining their performance in terms of ionic conductivity and transport number, to improve the efficiency and safety of LIBs.

Electrooxidation of acetaldehyde (ethanal) in aqueous and ethanol alkaline solution on Pd-modified glassy carbon and silver electrode was studied. The suppression of alcohol oxidation in the presence of aldehyde in solution was shown. This effect was used to estimate the possibility of selective detection of aldehyde in the presence of alcohol. The ability of quantitative detection of acetaldehyde in 1, 4, and 12 M ethanol solutions was demonstrated, while the qualitative analysis remains impossible by the use of Pd catalyst due to its activity in ethanol oxidation reaction in blank solutions.