Electrochimica Acta最新文献

In the present study, the inhibition mechanisms and the adsorption kinetics of a film-forming amine (N-oleyl-1,3-propanediamine, OLDA) were investigated on a carbon steel surface in various corrosive environments, relevant to industrial water/steam circuits. In situ electrochemical characterizations including Electrochemical Impedance Spectroscopy (EIS) and polarization curves were combined with ex situ surface analysis, such as Polarization Modulation Infrared Reflection Absorption Spectroscopy (PM-IRRAS) and Raman Spectroscopy. OLDA acts as a mixed inhibitor for all the studied conditions. In a deaerated medium, OLDA adsorption is temperature-independent (25 °C–50 °C) and PM-IRRAS analyses reveal the formation of a monolayer (thickness of about 1.6 nm) on the steel surface. In aerated media, mixed OLDA/corrosion products layers are formed exceeding the monolayer thickness (about 20 nm). Finally, the presence of a well-defined time constant in the high frequency range in impedance spectra is correlated with the accumulation of OLDA molecules with corrosion products.

CoS₂ with high thermal stability is commonly used as cathode material for thermal batteries, however, its practical performance is limited by insufficient electrochemical reactions during discharge. Enlighted by metal-doping that can regulate the electronic environment and lattice structure, high-energy Co_0.8Fe_0.2S₂ is successfully prepared by solid-state methods. Remarkably, with a current density of 0.3 A·cm⁻² at a cutoff voltage of 1.42 V under 550 °C, Co_0.8Fe_0.2S₂ exhibits excellent performance with a prolonged discharge platform and decreased resistance (0.23 Ω), generating an ultrahigh specific capacity of 652 mAh·g⁻¹_, which is 31 % higher than that of pure CoS₂. Our research indicates that Co_0.8Fe_0.2S₂ is suitable for high-energy and high-temperature thermal batteries. The feasibility of solid-state synthesis of pure-phase bimetallic disulfides has been verified as well, paving the way for industrial application of Co_0.8Fe_0.2S₂.

Silicon is capable of delivering a high theoretical specific capacity (4200 mAh g^-1) in lithium-ion batteries. However, silicon has poor electrical conductivity, huge volume expansion (∼300%), and unstable solid electrolyte interface (SEI) film, especially for micron-sized silicon particles. We proposed and prepared a novel vertical carbon (VG) coating on a porous silicon (p-Si) microparticle structure, which effectively alleviated the volume expansion and inhibited the interface reaction. The synthesized porous silicon p-Si@VG composite exhibited significant enhanced cycling stability and an excellent reversible capacity of 1563 mAh g^-1 (capacity retention of 48.6%) after 200 cycles. The vertical carbon nanosheet structure constructed a three-dimensional conductive network. Therefore, the p-Si@VG composite showed better rate capability and higher lithium-ion diffusion rates. This work is expected to promote the application of micron Si-based composites in lithium-ion batteries.

Sulfide SSEs (solid-state electrolytes) with high ionic conductivity are attractive for developing high-safety all-solid-state batteries (ASSBs). However, the poor chemical stability of sulfide SSEs toward moisture is a significant problem. Though the decomposition products when exposed to moisture and a possible property recovery by heat treatment are reported, the evolution of surface species in related to moisture exposure and to heat treatment is not clearly identified. This study applies in situ DRIFTS (diffuse reflectance infrared Fourier-transformed spectroscopy) analysis to examine the evolution of the surface species over pristine Li₆PS₅Cl (LPSC), during moisture exposure, and during heat treatment, complementary with tools like XRD, Raman, etc. The observed surface impurities over pristine LPSC include LiCl·H₂O, LiOH·H₂O, S₃P-SH, PS_4-xO_x, SO_x and carbonate species. Moisture exposure leads to increasing accumulation of these species over LPSC and evolving hydrogen sulfide. A stepwise heat treatment up to 480 °C illustrates the sequential removal of hydrated water, the decomposition of carbonate, LiOH, and PS_4-xO_x, leaving species like LiCl, Li₂O, and PO₄ on the surface. The EIS results shows a gradual increase in the ionic conductivity of LPSC with increasing heating temperature, mainly owing to the decreasing surface layer impedance. This strongly suggests that the surface species govern the properties of LPSC. When using the pristine LPSC after heat treatment at 480 °C, the Li||pristine LPSCHT||Li symmetric cell demonstrates a decreased polarization and a much-enhanced cycle stability comparing to the Li||pristine LPSC||Li symmetric cell.

In this work, Poly(o-phenylenediamine) (POPD) and zinc oxide (ZnO) nanoparticles were electrochemically deposited on GCN (graphitic carbon nitride) coated TCFP (Toray carbon fiber paper) electrode. The modified electrode ZnO-POPD-GCN-TCFP was assessed by Field emission scanning electron microscopy (FESEM), X-ray diffraction analysis (XRD), and X-ray photoelectron spectroscopy (XPS) studies. The electrochemical studies were carried out via cyclic voltammetry (CV) and electrochemical impedance spectroscopic (EIS) methods. The developed electrode was employed for the oxidation of furfuryl alcohol (FA) using 4-ACT (4-acetamido TEMPO) as a mediator in an alkaline medium via bulk electrolysis. Proton nuclear magnetic resonance (¹H NMR) spectroscopy was used to characterize the final product. The oxidation of FA to furfural was accelerated by the heterogeneous catalyst ZnO-POPD-GCN-TCFP electrode owing to its good electrocatalytic activity and stability. Hence, a sustainable electrochemical method for synthesizing furfural, with significance in the realm of green chemistry, was developed. The Electro-oxidation of FA offers a clean alternative to traditional methods utilizing electricity, potentially from renewable sources, to drive the reaction, reducing reliance on harsh chemicals and minimizing environmental impact. By adjusting parameters like electrode potential and electrolyte composition, it is possible to optimize the reaction conditions for furfural production with optimal yield, which has several applications in daily life.

We describe the design and development of a rotating disk electrode (RDE) cell capable of operating at pressures up to 200 bar and temperatures up to 200 °C. This setup enables electrochemical surface characterization through techniques such as voltammetry and impedance spectroscopy, under different mass transport regimes. Furthermore, evaluation of catalytic performance, including CO₂ reduction, is possible as the system works in a semi-continuous mode interfaced with online gas sample measurements. As a proof of concept of the high-pressure cell designed, we examined the temperature-dependent changes in the cyclic voltammograms (CVs) of polycrystalline gold up to 150 °C and 50 bar. Additionally, online catalytic performance of CO₂ reduction to CO on a rotating polycrystalline gold disk electrode was investigated under different pressure and temperature. Our results indicate a positive impact of temperature on the faradaic efficiency (FE) towards CO up to 50 °C, beyond which a rapid drop in performance was observed at atmospheric pressure. Conversely, increasing pressure positively affected CO₂ solubility in the electrolyte, resulting in enhanced FE towards CO, reaching approximately 90 % at 6 bar compared to 40 % at atmospheric pressure. Notably, further increases in pressure did not significantly alter the FE, but led to higher current densities. Moreover, at pressures exceeding 6 bar, we observed a plateau in efficiency at temperatures higher than 50 °C. This observation suggests that increasing pressure can sustain CO₂ electrolysis, validating the hypothesis that increasing CO₂ solubility would suppress catalytic decay at higher temperatures. This study opens up promising avenues for future investigations in electrocatalysis, ranging from fundamental explorations of surface modifications induced by variations in temperature and pressure to the development of high-performance catalysts.

A high entropy oxides (HEOs) has been proposed as a promising electrocatalyst for electrochemical water splitting reaction owing to their distinctive catalytic activity, stability, and tuneable electronic structure. In this work, a carbon infused HEOs (Ni_0.2 Co_0.2 Cr_0.2 Mn_0.2 V_0.2)₃O₄ nanoparticles were synthesized via a single step process through a carbonaceous thermal plasma (Ar-CO₂CH₄) medium. Here, carbon infused HEOs were utilized as an electrocatalyst for water splitting reaction in 1 M KOH electrolyte. A Carbon rich HEOs (HEO C6) nanoparticle exhibits excellent oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) performance with an overpotential of 243 and 217 mV to attain a current density of 50 mA cm^-2, respectively. The fabricated two-electrode device requires only a 1.596 V as cell voltage to meet a current density of 10 mA cm^-2. This study provides a new platform for a large-scale hydrogen production by utilizing carbon supported HEOs as an electrocatalyst.

The growing demand for energy storage is required with the development of the intermittent renewable energy. Supercapacitors are a promising energy storage equipment, but their capacitive performance mainly depend on the electrode material. To obtain a high-performance electrode material for supercapacitors, in this work, a carbon-Ni/NiO/Ni(OH)₂ composite was prepared from pine sawdust as the carbon precursor by integrating CO₂ gasification and electrochemical deposition. It is found that the carbon-ternary nickel composite shows good electrochemical performance due to synergistic effect of the unique hierarchical structure and components involving porous carbon skeleton, Ni⁰ and NiO nanoparticles, and Ni(OH)₂ microspheres. The composite displays the specific capacitance of 1875.6 F/g (or 937.8 C/g) at a current density of 1 A/g in a traditional three-electrode system. The assembled asymmetric supercapacitor device presents a potential window of 1.6 V, along with the energy density of 38.24 Wh/kg at the power density of 400 W/kg (or 22.60 Wh/kg at 2000 W/kg). After 6000 charge-discharge cycles, the capacitance retention ratio of the assembled supercapacitor reaches up to 105 %, exhibiting a good application potential. This work provides a novel and handy strategy for preparation of ternary nickel-based composite for advanced supercapacitors.

4-Nitrophenol (4-NP) is one of the most common and extensive toxic threats to the environment; hence there is always a need to develop a robust analytical method. In this study, we present MXene-based AgBiS₂ nanocomposite as an electrochemical sensing platform for detecting 4-NP. The synergistic combination of MXene and AgBiS₂ within the composite structure enhances electrocatalytic performance, resulting in a highly sensitive and selective sensor. The electrochemical performance of the MXene-AgBiS₂ modified GCE was evaluated through cyclic voltammetry (CV) and differential pulse voltammetry (DPV) analyses. The sensor exhibited excellent electrochemical properties, including a low detection limit (LOD) of 0.00254 µM (should consider the method how to get such low LOD – due to 10 times of the lowest conc tested S/N = 3, high sensitivity of 5.862 µA µM⁻¹ cm⁻², and a wide linear range (0.02–1869 µM). The sensor also demonstrated good selectivity against various interference compounds such as Di-Nitrophenol, Ortho-Nitrophenol, Copper, Cobalt, sodium, Manganese, Zinc, Glucose (GLU), Urea (Ur), Dopamine (DA), Ascorbic acid, and Uric Acid. Along with reproducibility, repeatability, and stability also performed shows, 2.21 %, and 2.71 % respectively. Our nanocomposite sensor, utilizing MXene-based AgBiS₂, proves its practicality in real-time tap water analysis. This bridge between lab studies and environmental monitoring marks a significant advancement. The unique properties of our sensor enhance electrochemical sensing, providing a promising solution for swift on-site detection of 4-NP in water, potentially revolutionizing pollutant management.

In response to the dynamic advancement of our growing world, there is a tenacious need for sophisticated technologies and continuous refinement of existing knowledge through rigorous scientific endeavors, all with a focus on achieving sustainable development goals for a cleaner and more prosperous future. In this context, this study involves a novel approach to the synthesis of highly porous and stable nickel oxide (NiO) nanoflakes assembled with stacked nanosheet thin films through hydrothermal methods. These films are in-detail examined for their redox-active chromo-supercapacitive properties. The hydrothermal synthesis technique yields thin films with exceptional adhesion to the electrode surface, remarkable chemical stability, and suitable porous structure. These characteristics are strategically employed to facilitate rapid ion intercalation and deintercalation processes, thereby enhancing electrochemical activity. Notably, films deposited for 6-hour reaction times deliver a higher areal capacitance of 140 mF/cm² (and capacity of 70 mC/cm²) at 0.5 mA/cm², which is higher than other electrodes and earlier reports. In-situ, optical investigations further underscore the high coloration efficiency of 44.14 cm²/C, coupled with large optical modulation of 56.5 % and enduring the electrochemical and electrochromic stability. Further research and optimization of NiO-based materials hold significant potential for the development of efficient, smart, and sustainable energy storage solutions in the evolving field of electrochromic supercapacitors to meet the demands of next-generation electronic systems.