Ionics最新文献

This study used the ultrasonic spray technique to examine how Sr doping (0–5%) influences the structural, morphological, and electrochemical properties of CuO deposited on fluorine tin oxide (FTO) substrate. A particular property was highlighted: the XRD-Raman spectrum confirmed the successful production of Cupric oxide (CuO) at 0%Sr, followed by a significant shift in the XRD peaks at 3%Sr as a result of the majority insertion of Sr in the CuO lattice structure. Nevertheless, when the %Sr was increased to 5%, a simultaneous formation of the Sr-CuO nanophase was favored over the incorporation of strontium into the CuO. EDX and SEM-morphology studies show successively the presence of the three deposited elements Cu, Sr, and O, as well as a significant reduction in the size of CuO nano-structures as the %-Sr doping level increases, respectively. From an optical point of view, this structural-morphological modification due to doping affected the absorption property and, as a result, the bandgap E_g decreases slightly from 1.52 to 1.48 and then 1.44 eV, respectively, for 1%-Sr and 3%-Sr, but increases to 1.46 eV for the pass 3 → 5%-Sr. In addition, the CV (cyclic voltammetry) and the GCD (galvanostatic discharge) tests showed that this structural change led to a significant change in the energy storage capacity of Sr-doped CuO-thin films electrodes. The maximum capacity value has increased from 120 mF/cm² (0%) to 165 mF/cm² (3%) and then to 139 mF/cm² for 5%-Sr, which shows that the Sr doping of CuO can improve its pseudocapacitive properties.

Precisely forecasting the State of Health (SOH) of lithium-ion batteries is essential to enhance vehicle safety and refine battery management systems. This study seeks to address the shortcomings of conventional approaches in feature representation, temporal dependency modeling, and forecasting precision by introducing an attention-enhanced bidirectional long short-term memory (Bi LSTM) model for battery SOH estimation. First, the method selects five key features highly correlated with aging from the battery’s charge–discharge cycles as model inputs and validates their effectiveness using Pearson correlation coefficients to ensure the reliability and representativeness of the input data. During model construction, Bi LSTM is employed to fully exploit the temporal dependencies between features, and the attention mechanism dynamically adjusts feature weights, enabling the model to concentrate on more predictive information. Finally, evaluation and validation using NASA’s publicly accessible lithium-ion battery dataset demonstrate the method’s superior effectiveness in SOH prediction for both individual and similar batteries. Compared to a standard LSTM model, it achieves an average decrease of approximately 1.27% in root mean square error (RMSE) and around 1.26% in mean absolute error (MAE). This improvement enhances the model’s ability to generalize while effectively capturing the battery capacity degradation trend and reducing prediction errors.

The electrochemical behavior of rare earth ions (RE³⁺) doped CaCO₃/PEG nanocomposites (RE³⁺ = 0.08 mol Y, La, and Gd) synthesized via a biomimetic method using dolomite rock as a carbonate source was thoroughly analyzed through XRD, FTIR, UV–Vis-DRS, Band gap, PL, FE-SEM, and HR-TEM analyses. All the prepared products were in rhombohedral structure, and the obtained crystallite size was in the range of 25–23 nm. The average microstrain and dislocation density of the products were also calculated, and the values are 1.33, 1.35, and 1.73 × 10⁻³ and 12.69, 13.21, and 22.21 × 10¹⁴ for Y, La, and Gd-doped CaCO₃/PEG nanocomposites. The FTIR results revealed the presence of characteristic peaks (477, 479, and 465 cm⁻¹), which confirmed that the products were Y, La, and Gd-doped CaCO₃/PEG nanocomposites. From the UV–Vis-DRS, band gap, and PL analyses, 0.08 mol RE³⁺ ions doped CaCO₃/PEG nanocomposites demonstrate blue shift absorption and emission values with increasing band gap values (4.50, 4.58, and 4.70 eV). The formation of spherical-shaped morphology was affirmed by FE-SEM and HR-TEM analyses, and the calculated particle size was in the range of 32–26 nm. The pseudocapacitive behavior of 0.08 mol Y, La, and Gd-doped CaCO₃/PEG nanocomposite electrodes was confirmed via CV, GCD, and EIS. They showed specific capacitances of 261, 270, and 288 F/g, respectively, at 5 mV/s using a CV curve, with 97% cyclic stability over 1000 cycles. Energy and power density were calculated, and the values are 51.6, 52.6, and 53.4 Wh kg⁻¹ and 1416.28, 1229.21, and 1221.347 W kg⁻¹ for Y³⁺, La³⁺, and Gd³⁺ anchored CaCO₃/PEG nanocomposites, at 1 A/g respectively.

This study synthesizes Ni-doped BiOCl/MXene composite photocatalysts via a one-pot hydrothermal method for enhanced CO₂ reduction. The ternary heterostructure with highly dispersed Ni²⁺/Ni³⁺ species significantly improves charge separation efficiency, as evidenced by a 2.02-fold increase in carrier lifetime (4.72 ns) from time-resolved photoluminescence measurements. Photoelectrochemical tests demonstrate a photocurrent density of 65.3 μA/cm², representing a 4.3-fold enhancement over pristine BiOCl, alongside minimal charge transfer resistance. In photocatalytic CO₂ reduction under simulated sunlight, Ni/BiOCl/MXene achieves 91% CO selectivity and a cumulative yield of 53.23 μmol/g over 5 h, corresponding to a production rate of 10.65 μmol/(g·h). This performance reflects a 5.1-fold total yield improvement and a 3.84-fold increase attributable to MXene’s conductive network. Control experiments confirm nickel’s dual role in refining reaction sites and promoting CO₂ adsorption, with CO₂-TPD analysis revealing a distinct 350 °C desorption peak indicative of Ni²⁺-stabilized HCOO* intermediates. The catalyst maintains 92% initial activity after five cycles, demonstrating exceptional stability. This work establishes a synergistic mechanism where MXene facilitates interfacial electron transfer while nickel doping optimizes intermediate stabilization, providing new design principles for efficient solar fuel generation.

Owing to the relatively richer reserves of cobalt than that of ruthenium, multiple valence states of cobalt, and the highly ionic Co-F bond, CoF₂ nanomaterial emerges as a promising candidate for the electrode material in alkaline aqueous supercapacitors. Currently, the synthesis process of CoF₂ nanomaterial typically requires an ultra-low temperature (0 °C), or a high temperature (> 180 °C) and/or an inert atmosphere environment, which necessitates the use of much electric energy supply and/or costly equipment. It is of great significance to explore a cheaper preparation method for the CoF₂ nanomaterial. This study presents a novel and low-cost two-step method to synthesize CoF₂ nanoparticles as high-performance electrode materials for alkaline aqueous supercapacitors. The process involves liquid precipitation of CoF₂·4H₂O at room temperature, followed by Solvothermal treatment at 120 °C in air, eliminating the need for inert atmospheres, high temperatures, or costly equipment. The resulting CoF₂ nanoparticles (20–100 nm) exhibit a hierarchical porous structure, providing a large specific surface area (17.85 m²/g) and enhanced electrolyte accessibility. Electrochemical tests reveal a high voltammetric Specific capacitance of 278.1 Fg⁻¹ at 0.005 Vs⁻¹ and discharge Specific capacitance of 440.3 Fg⁻¹ at 0.5 Ag⁻¹, attributed to combined pseudocapacitive and intercalation mechanisms. The material also demonstrates Stable cycling performance over 5000 cycles. This work offers a sustainable pathway for synthesizing advanced electrode materials for energy storage applications.

Hexavalent chromium (Cr(VI)) is a highly toxic and carcinogenic contaminant that poses severe environmental and health hazards. Photocatalytic reduction using Cu₂O-based composites has emerged as a promising approach for Cr(VI) detoxification due to Cu₂O's visible light responsiveness, tunable band structure, and excellent redox properties. This mini-review provides an overview of recent advancements in Cu₂O-based photocatalysts for Cr(VI) reduction, with a focus on environmental risks of chromium ions, a case study of Cr(VI) pollution, synthesis strategies of Cu₂O-based photocatalysts, structural modifications, and photocatalytic mechanisms. Key factors influencing photocatalytic performance, including heterojunction formation, co-catalyst loading, charge separation efficiency, and reaction conditions, are critically examined. Additionally, the challenges associated with Cu₂O-based photocatalysts, such as photo-corrosion and scalability limitations, are discussed along with potential strategies to overcome them. Finally, future research directions for enhancing Cu₂O-based photocatalytic systems through material innovations and sustainable implementation are outlined. This review aims to provide valuable insights into the development of efficient and stable Cu₂O-based photocatalysts for chromium remediation, contributing to cleaner and safer water resources.

Designing efficient and cost-effective catalysts for the oxygen reduction reaction (ORR) is critical for advancing fuel cell technologies. In this work, we employ density functional theory (DFT) to systematically investigate the catalytic properties of PdAg alloys with varying atomic compositions. Among the configurations studied, the Pd₂Ag₂ surface exhibits the most favorable free energy profile for the four-electron ORR pathway, with a notably low overpotential. Electronic structure analysis reveals a d-band center shift and enhanced adsorption balance as key contributors to its superior catalytic activity.To provide a foundation for the experimental realization of PdAg alloys, we fabricated pure silver electrodes via high-temperature sintering at 500 °C, 600 °C, and 700 °C. Morphological characterization using optical microscopy and scanning electron microscopy (SEM) demonstrates that sintering temperature significantly influences the grain structure and surface crystallinity of the Ag electrodes, offering a tunable platform for future Pd integration.This combined theoretical–experimental approach offers both a clear computational design principle and a practical fabrication pathway for the development of high-performance PdAg catalysts for ORR applications.

A washing treatment process for cathode materials is crucial for eliminating residual lithium on the surface, which can effectively enhance lithium-ion battery cell performance. In this work, LiNi_0.59Co_0.3Ti_0.1Al_0.01O₂ (NCTA) cathode materials were synthesized using the co-precipitation method, and the effects of different washing durations with water were investigated. XRD results revealed that the synthesized sample was a single phase with a hexagonal layered structure of the R-3 m space group. Rietveld refinements revealed that the washed sample exhibited lower cation mixing compared to the unwashed sample, which showed that the unwashed samples had particle agglomeration and the existence of Li residue on the surface of the cathode materials. Interestingly, after the washing treatment, the NCTA appeared as single crystal particles with clean, smooth surfaces. Charge/discharge studies demonstrated that the washed sample showed a significant increase in initial discharge capacity compared to the unwashed sample. The optimal washing duration was found to be 15 min (W15), resulting in the best initial discharge specific capacity of 161.86 mAh/g at 0.1 C with a capacity retention of 81.9% after 100 cycles at room temperature. The W15 sample also shows a great rate capability compared to the unwashed sample, as evident by having a higher discharge capacity at each C-rate. This excellent performance can be attributed to the good structural integrity, single crystal morphology, and lower resistance of the W15 sample compared to the unwashed sample. This work demonstrates that the water washing treatment is efficient in removing Li residue on the surface and improving the electrochemical performances.

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Water dye contamination has been increasing recently, which has serious toxicological repercussions for human health and the ecosystem. In this study, we synthesized a series of spinel ferrite nanomaterials with the composition Mg_1-xNi_xFeCrO₄ (0.0 ≤ x ≤ 1.0) using a cost-effective sol–gel method. The structural, morphological, compositional, thermal, and optical properties of the synthesized samples were systematically investigated using XRD, FTIR, SEM, EDX, TGA, and UV-DRS. XRD results confirmed the formation of single-phase spinel structures, with crystallite size influenced by the Ni substitution level. FTIR analysis verified the characteristic vibrational modes of spinel ferrites. SEM images revealed uniform morphology with particle agglomeration, while EDX confirmed the elemental composition and homogeneity. TGA demonstrated good thermal stability of the materials. UV-DRS analysis revealed that increasing Ni content systematically tuned the band gap energy, thereby influencing the photocatalytic activity. Among the series, the MgFeCrO₄ (x = 0.0) sample exhibited the highest photocatalytic efficiency, achieving 96% degradation of Direct Black 122 dye within just 15 min under UV–visible light irradiation. The improved performance is ascribed to its suitable band gap, efficient charge carrier separation, and surface characteristics. These findings demonstrate the strong potential of MgFeCrO₄ as an efficient photocatalyst for wastewater treatment.

The design of a high-performance electrocatalyst for ethanol oxidation is a key requirement for fabricating direct ethanol fuel cells with high efficiency and durability. Herein, palladium is integrated with MnO₂/delaminated boron (B) to form MnO₂-B-Pd nanocomposite. The ethanol electrooxidation studies of MnO₂-B-Pd nanocomposite and Pd–C were investigated by recording cyclic voltammograms (CVs) in 2 M NaOH + 2 M ethanol, which revealed that MnO₂-B-Pd nanocomposite demonstrated higher mass activity of 592.75 mA mg⁻¹ Pd as compared to Pd–C. Furthermore, the onset potential for the forward scan for MnO₂-B-Pd nanocomposite is more negative (− 0.233 V), as compared to that of Pd–C (− 0.191 V), which suggests a lower electrocatalytic activation barrier and thus improved reaction kinetics of ethanol. The kinetics studies revealed that MnO₂-B-Pd has a faster charge transfer reaction (electron transfer rate constant (k^o) = 3.68 × 10⁻⁴), and the overall electron transfer is controlled by diffusion of the reactant at the electrode/electrolyte interfaces.