Journal of Solid State Electrochemistry最新文献

One promising method of converting solar power into chemical fuel and minimizing power shortages is photoelectrochemical water splitting, which can produce hydrogen and improve environmental health. Au functionalized In₂S₃ nanoflowers were synthesized with an easy chemical vapor deposition (CVD) and chemical reduction technique, respectively. Surface characterization techniques such as Field effect scanning electron microscopy (FESEM) and Elemental mapping analysis (EDX) show the uniform functionalization and synthesis of Au functionalized In₂S₃. High optical absorption and higher electron–hole pair concentration are generated due to an in-built electric field, reducing the recombination rate at the interface and resulting in a high photocurrent density value of 5.5 mAcm⁻² and IPCE (incident photon to the current conversion efficiency) value of 80%. The synthesized Au functionalized In₂S₃ nanoflowers demonstrated excellent durability and functionality for the oxidization process of water in sunlight.

Stainless steels are alternative materials for graphite bipolar plates in proton exchange membrane (PEM) fuel cells. Plasma electrolytic nitriding (PEN) of stainless steel 316L samples was carried out in an aqueous solution of urea. Grazing incidence X-ray diffraction analysis revealed the presence of Fe₂N_0.94, iron oxide, and X-ray photoelectron spectroscopy results showed iron nitride, iron oxide, and chromium oxides on the PEN-modified 316L surface. The thickness of the modified layer is approximately 1.1 μm as determined with glow discharge optical emission spectroscopy. The PEN-modified surface exhibited a lower corrosion current density of 88 ± 15 µAcm⁻² and 57 ± 16 µAcm⁻² in the simulated anodic and cathodic environments, while bare samples showed a corrosion current density of 155 ± 31 µAcm⁻² and 156 ± 15 µAcm⁻² in respective environments. Electrochemical impedance spectroscopy at open circuit potential revealed that PEN-modified surface has more polarization resistance than bare samples, indicating improved corrosion resistance. However, the long-term potentiostatic studies for 8 h showed that PEN-modified samples have higher passive current densities of 17.7 µAcm⁻² and 4.2 µAcm⁻² in anodic and cathodic environments, whereas bare samples showed 1.4 µAcm⁻² and 0.6 µAcm⁻² in respective environments. The concentration of total dissolved metal ions after potentiostatic polarization is significantly reduced after PEN modification, where the PEN-modified samples showed only 2.37 mgL⁻¹ and 5.54 mgL⁻¹ in anodic and cathodic environments, while bare samples showed 16.99 mgL⁻¹ and 20.24 mgL⁻¹ in respective environments. Interfacial contact resistance (ICR) values for bare and PEN-modified 316L at a compaction load of 140 Ncm⁻² were 118.8 ± 4.6 mΩcm² and 26.8 ± 3.7 mΩcm², respectively.

Graphical Abstract

In this study, a multi-scale grain distribution was achieved in 0Cr17Ni13Mo5 super austenitic stainless steel through severe cold rolling followed by annealing at temperatures ranging from 500 to 1000 °C. The effects of this hierarchical microstructure on corrosion resistance were systematically investigated. The results show that the sample annealed at 1000 °C exhibits the best corrosion resistance, with a corrosion potential (E_corr) of − 0.12 V_SCE, a corrosion current density (j_corr) of 7 × 10⁻⁸ A/cm², and a polarization resistance (R_t) of 1,022,600 Ω·cm². Mott–Schottky analysis confirms that the 1000 °C annealed sample had the lowest donor density and the slowest corrosion rate, further supporting its superior corrosion resistance. This enhancement is primarily attributed to the formation of a bimodal grain structure, which facilitates the diffusion of Cr atoms toward the corroded surface, promoting the formation of a thicker passive film. In addition, annealing at 1000 °C reduces the precipitation of σ-phase at grain boundaries. Furthermore, the higher fractions of Σ CSL boundaries and Σ3 twin boundaries contribute to improved resistance to intergranular corrosion. 

In this study, we use density functional theory (DFT) with a Hubbard (U) parameter, implemented in the Quantum Espresso code, to investigate the interactions between Li-ions and the ZrS₂ monolayer under the influence of in-plane uniaxial and biaxial strains, specifically within the context of lithium-ion batteries. This is to ensure the ZrS₂ monolayer is more robust against the Coulomb forces arising from interactions between multiple lithium ions. This study objectively examines the impact of tensile and compressive strains ranging from − 5% to 5% on the energetic stability and electrochemical properties of the lithiated ZrS₂ electrode monolayer. For a single Li adatom on a 3 × 3 ZrS₂ monolayer, the compressed structure (at − 5% strain) becomes more energetically favorable, exhibiting a low adsorption energy of − 1.41 eV. In contrast, the stretched structure (at + 5% strain) has a higher adsorption energy of − 0.95 eV compared to the unstrained structure (− 1.16 eV), although exothermic interaction is maintained. The ZrS₂ electrode monolayer has a shallow energy barrier of 0.23 eV for Li-ion diffusion, indicating greater mobility, which is slightly enhanced by compressive strain. The application of − 5% (compressive strain) resulted in an average OCV of 0.93 V, and 0.78 V for unstrained, while + 5% (tensile strain) yielded an OCV of 0.69 V, which is in the range of commercial anode materials. The tensile strain on a ZrS₂ electrode monolayer would be more effective in mitigating the dendrite formation. The introduction of a Li adatom rearranged the conduction band minimum, leading to the hybridized Zr d orbital states crossing the Fermi level and becoming more populated as the number of Li adatoms increases, leading to a more conductive electrode. Additionally, the strain reduced the band gap, causing the induced electronic states to be continuous from the VBM to the CBM edges, which enhances the electronic conductivity of the material, ensuring the excellent LIBs operation during the charge and discharge processes.

Single-walled carbon nanotubes (SWCNTs), renowned for their excellent electrical conductivity, have long been recognized as an ideal conductive additive material. However, the high-quality and high-yield preparation of SWCNTs remains a significant challenge. In this study, we report the use of a catalyst consisting of magnesium oxide (MgO) as the substrate, with nickel (Ni) and tungsten (W) as the catalytic elements. After calcination, the catalyst formed a MgNiO₂ phase, which was then utilized in the chemical vapor deposition (CVD) method to prepare SWCNTs. The catalyst efficiency of SWCNTs reached 116% (the mass ratio of SWCNTs to catalyst). After acid treatment to remove metal impurities, the SWCNTs were incorporated as a conductive additive (5 wt%) in LiFePO₄ (LFP) lithium-ion batteries. The results demonstrate that the batteries containing this SWCNT conductive additive exhibited exceptional cycling and rate performance. At a 5 C discharge rate, the specific capacity reached 115.51 mAh/g. The capacity is still 123.93 mAh/g after 200 cycles at a 3 C discharge rate, with a retention rate of 90.90%. This test group had the lowest charge transfer impedance and the highest ion mobility rate when compared to the commercial carbon nanotubes and SuperP (SP) conductive agent control group. The findings of this study provide a simpler and more efficient method for the preparation of SWCNTs.

This study investigates the effects of annealing and of chelating agents, triethanolamine (TEA) and ethylenediaminetetraacetic acid (EDTA), on tin sulfide (SnS) thin films prepared by potentiostatic electrodeposition on ITO-coated glass substrates. The films were annealed at 250 °C for 30 min, under air and under the presence of sulfur. The cyclic voltammetry revealed that the chelating agent’s type impacts the kinetic parameters of the deposition process. It was found that EDTA leads to stable chelates with tin ions compared to the TEA agent. Moreover, chronoamperometry highlighted that TEA enhanced the film’s electrochemical deposition kinetics, resulting in thicker and more compact layers when compared to those achieved with EDTA. XRD analysis showed the successful deposition of orthorhombic SnS films and the improvement of crystallinity by the increase of crystallite size after annealing treatments, especially with sulfurization. Raman spectra confirmed the deposition of pure SnS without annealing, and when annealing, the formation of a small amount of SnS₂ and Sn₂S₃ tin sulfide’s secondary phases. SEM micrographs revealed grain growth and densification. EDX analysis highlighted that both chelating agents and annealing processes affect the elemental composition of the films. Finally, optical studies have demonstrated that annealing increases the band gap energy, and TEA-based films are better for photovoltaic applications.

To extract Lu from LiCl–KCl molten salt, the electrochemical behavior of Lu(III) were explored by different electrochemical methods. Cyclic voltammetry (CV), reverse chronopotentiometry (RCP) and square-wave voltammetry (SWV) demonstrated that Lu metal was formed by one-step three-electron transfer when Lu(III) was reduced on W electrode, and the electrode reaction is reversible controlled by diffusion. The diffusion coefficient of Lu(III) in molten salt was calculated to be 1.68 × 10^–5 cm² s⁻¹ by SWV. Only BiLu was formed when the co-deposition of Lu(III) and Bi(III) was conducted at 773 K, which was confirmed by anode chronopotentiometry. The influence of temperature on the types of Bi-Lu intermetallic compounds was also explored. In addition, the thermodynamic parameters of BiLu were estimated by open circuit chronopotentiometry. The extraction efficiency of Lu(III) reach up to 89.54% when the constant-current electrolysis continued for 12 h based on the result of ICP-OES, and the product was characterized by SEM–EDS.

The series of the Fe_xTi_2-2xNb_10+xO₂₉ solid solutions (x = 0.0, 0.4, 0.5, 0.6, 1.0) with the monoclinic Wadsley-Roth crystallographic shear structure were prepared by the mechanochemically assisted solid-state synthesis and studied as anode materials for lithium-ion batteries. The phase purity of the synthesized samples was confirmed by X-ray powder diffraction and Mössbauer spectroscopy. The galvanostatic intermittent titration technique (GITT) results show that with an increase in the iron content in Fe_xTi_2-2xNb_10+xO₂₉, the Li⁺ diffusion coefficient, D_Li+, increases at the plateau region at 1.67 V, whereas it decreases in the region at 1.5–1.2 V. Fe_0.5TiNb_10.5O₂₉ represents a compromise between these two correlations; therefore, this sample has the highest average D_Li+ among the other Fe_xTi_2-2xNb_10+xO₂₉ samples. Therefore, the optimal composition, Fe_0.5TiNb_10.5O₂₉, exhibits the value of the specific charge capacity of 230 and 197 mAh g⁻¹ at the cycling rates of 10C and 20C, respectively, which is higher than those of Ti₂Nb₁₀O₂₉ (167 and 93 mAh g⁻¹) and FeNb₁₁O₂₉ (157 and 80 mAh g⁻¹). 

Graphical abstract

Applicability of a self-powered cascade bipolar electrode system for driving chemical charge transfer reactions (which under typical conditions do not occur spontaneously) was tested. As a proof of concept, oxidation of silver to silver ions was studied because the controlled release of small amounts of silver ions is of practical significance, e.g., due to their antibacterial activity. Since bacterial infection results in local acidification, effective bacteria killing by silver ions requires “stimuli-pH responsive” silver ions releasing arrangements. The applied cascade system consists of two bipolar electrodes (circuits) arranged in closed mode. One of the circuits, the “driving” one, is characterized by a high potential difference between opposite ends of the electrode (zinc wire connected with platinum electrode in the presence of hydrogen ions). Therefore, this bipolar electrode can trigger the silver oxidation process at the second bipolar electrode (silver/silver chloride electrode connected with silver wire). Cascade bipolar electrode architecture opens the possibility of tailored coupling chemical processes without need of electrochemical instrumentation. In the studied simple system, the process of silver oxidation can be effectively stimulated and controlled by the concentration of hydrogen ions contacting the platinum electrode, as a model of “stimuli-pH responsive” system, where lower pH actuates a higher rate of silver ion release. Electrochemical experiments were supplemented by quantification of silver and zinc released (ICP MS, UV/Vis). Basing on these results, some more general predictions concerning charge transfer reactions control and their sensitivity to external conditions for bipolar electrode systems were proposed.