Ionics最新文献

The development of non-noble metal oxygen evolution reaction (OER) catalysts that combine low overpotential and long-term cycling stability at high current densities is key to overcoming the bottleneck in water electrolysis for hydrogen production technology. This work successfully prepared a molybdenum-doped cobalt-nickel-iron based sulfide catalyst (Mo-CoNiFe-S/NF) on nickel foam (NF) through a synergistic strategy involving two-step electrodeposition combined with hydrothermal sulfurization. This catalyst demonstrates outstanding OER catalytic performance in 1 mol/L KOH solution: it requires an overpotential of only 69.7 mV to reach a current density of 10 mA cm⁻², and a low overpotential of 346.3 mV at 100 mA cm⁻², with a Tafel slope as low as 37.3 mV dec⁻¹. These metrics are significantly superior to those of the molybdenum-undoped CoNiFe-S/NF and pure NF catalysts. This catalyst exhibits excellent potential for industrial application: operating continuously at a current density of 50 mA cm⁻² for 24 h, the current density decayed only from 50 mA cm⁻² to 48.8 mA cm⁻², representing a decay rate of merely 2.4%, while achieving a high Faraday efficiency of 95.36%. The doping with trace amounts of molybdenum and the sulfurization treatment enhance catalytic performance through multiple pathways: constructing a Ni₃S₂/(Co, Ni)₃S₄/FeS multiphase composite system to leverage component synergy; forming an interconnected network-like porous structure to expand the electrochemical active surface area (C_dl reaching 26.6 mF cm⁻²); and inducing electronic reconstruction to increase the electron density of active metal sites, thereby optimizing the adsorption-desorption kinetics of oxygen intermediates.

Accurate estimation of lithium-ion battery State of Health (SOH) remains challenging because most existing methods rely on full charging cycles, are sensitive to noise and capacity regeneration, or require manual hyperparameter tuning that limits generalization across cells and datasets. To address these issues, this study proposes a hybrid CNN–BiLSTM–Attention framework optimized by a Genetic Grey Wolf Optimizer (GGWO) for SOH estimation using only two informative features extracted from partial charging data via Incremental Capacity Analysis. The CNN extracts local degradation patterns, the BiLSTM captures long-range temporal dependencies, and the attention mechanism adaptively emphasizes salient temporal information, while the GGWO automatically searches for optimal hyperparameters to improve robustness and accuracy. Extensive experiments on both public CALCE datasets and a private multi-cell LBP dataset demonstrate that the proposed model achieves superior estimation performance across varying temperatures and loading conditions. The GGWO-optimized model attains a minimum MAE of 0.42% and RMSE of 0.51%, consistently outperforming conventional machine learning baselines as well as the non-optimized CNN–BiLSTM–Attention model. These results confirm the model’s strong generalization capability and its suitability for real-time implementation in battery management systems.

This study successfully prepared high-density LiFePO₄/C composite materials using a ternary co-doping strategy of Nb₂O₅, TiO₂, and V₂O₅, combined with particle size optimization and control techniques. The substitution of Nb⁵⁺ for Li⁺ positions can widen the diffusion channels for Li⁺ and enhance its diffusion kinetics. The replacement of Fe²⁺ by Ti⁴⁺ can stabilize the crystal structure, reduce volume changes during charge-discharge processes, and improve cycling stability. The substitution of Fe²⁺ by V^4⁺ and the introduction of electron defects can increase electronic conductivity. The synergistic co-doping of Nb⁵⁺, Ti⁴⁺, and V^4⁺ increased the electrical conductivity of the LFP material from 2.0 × 10^− 1 to 2.6 × 10^− 1 S cm^− 1 and the Li⁺ diffusion coefficient from 7.65 × 10^− 13 to 2.39 × 10^− 12 cm²s^− 1. Moreover, by optimizing the particle size distribution and adopting a non-uniform particle grading strategy, small particles can efficiently fill the gaps between large particles, reducing porosity and further increasing the compaction density. The final Li₀.₉₉₀Nb₀.₀₁₀Fe₀.₉₉₀Ti₀.₀₀₅V₀.₀₀₅PO₄ material achieved an industry-leading compaction density of 2.72 g cm^− 3 under a pressure of 226 MPa. Electrochemical tests showed that the discharge capacities at 0.2 C and 5 C rates were 166.2 mAh g^− 1 and 142.4 mAh g^− 1, respectively, and the capacity retention rate after 1000 cycles at 5 C was 91.34%. The assembled 14,500 cylindrical battery exhibited excellent volumetric energy density (0.2 C: 1166.27 Wh L^− 1, 1 C: 1109.62 Wh L^− 1). This research provides an effective material design strategy for the development of high-energy-density lithium iron phosphate batteries.

Sodium-ion batteries (SIBs) have emerged as a promising complement to lithium-ion counterparts, owing to their advantages of abundant resources, low cost, and high safety. Among the polyanion-type cathode materials, Na₃Fe₂(PO₄)(P₂O₇) (NFPP) has garnered significant attention due to its stable three-dimensional framework and environmentally friendly characteristics. However, its inherent low electronic conductivity has hindered practical application. This work presents a modification strategy to address this limitation. By constructing a three-dimensional continuous conductive network within the NFPP composite material (NFPP@C/CNT-rGO) through the integration of carbon nanotubes (CNT), reduced graphene oxide (rGO), and amorphous carbon coating, the electronic conductivity is significantly enhanced, and sodium-ion diffusion sites are optimized. Electrochemical evaluation demonstrates that the NFPP@C/CNT-rGO half-cell delivers a reversible capacity of 113.3 mAh g⁻¹ at 0.1 C, with a capacity retention rate of 70.7% after 6000 cycles at a high rate of 10 C, while maintaining a stable Coulombic efficiency close to 100%. Notably, at 20 C, the capacity reaches 70.2 mAh g⁻¹, far surpassing that of NFPP@C. Furthermore, the assembled NFPP@C/CNT-rGO || HC full cell exhibits a capacity retention rate of 78.4% after 300 cycles at 1 C, validating the material’s practical application potential. This study introduces a novel approach to enhance the performance of iron-based polyanion cathodes in sodium-ion batteries by constructing carbon conductive networks with multi-morphological structures, thereby paving the way for the practical application of sodium-ion batteries.

With the expansion of Energy Storage Power Stations (ESPS), the state assessment of Lithium-ion Batteries (LIBs) is crucial for system safety and efficiency. This study proposes a fusion algorithm combining adaptive extended Kalman filtering and particle swarm optimization to address traditional methods’ limitations in adapting to battery dynamic characteristics and reducing estimation errors. This algorithm dynamically adjusts the noise covariance matrix through an adaptive noise update mechanism, enhances the global search capability of particle swarm optimization, and makes the estimation results more accurate and reliable. Experiments showed the method’s loss values decreased to 0.1 and 0.06 across two datasets, with mean absolute errors in SOC estimation of only 0.98% and 0.62%. The identification error rapidly decreased with iterations, remaining between 0.2% and 0.3%. In practical applications, the method maintained battery SOC at 80%-90% under high-frequency low-power pulse conditions and long-term high-power continuous conditions with 4A current and approximately 1-second transient response. The designed state evaluation model effectively alleviates energy storage system pressure, reduces energy loss, and extends battery life, providing a new direction for LIBs state evaluation in ESPS and contributing to improved operational efficiency and safety.

Tuning the properties of precursor materials is essential for unlocking the full potential of lithium-ion battery cathodes. Herein, a one step crystallization strategy for synthesizing battery-grade Mn₃O₄ directly from manganese sulfate is reported. Mn₃O₄ with high tap density and controllable particle size was prepared through the facile and efficient process. The resulting material exhibited a median particle size of 10 μm, a remarkably high tap density of 2.75 g·cm^− 3, and a low specific surface area of 0.389 m²·g^− 1. Furthermore, the D50 was reduced to 6 μm while maintaining an excellent tap density of 2.61 g·cm^− 3 and a low specific surface area of 0.574 m²·g^− 1 by stabilizing the pH at 7.25 during the synthesis. When used as precursors, Mn₃O₄ particles of 6 μm and 10 μm led to LiMn₂O₄ cathodes with distinct electrochemical performance: LMO-6 demonstrated superior rate capability, with discharge capacities of 129.01, 125.94, and 122.69 mAh·g^− 1 at 0.1, 0.2, and 0.5 C, respectively. In contrast, LMO-10 showed outstanding cycle stability, maintaining a capacity retention of 90.58% after 300 cycles at 1 C. This work provides a facile and efficient route for tailoring Mn₃O₄ precursors to design LiMn₂O₄ cathodes.

A novel biodegradable biopolymer electrolyte (BPE) was developed using carboxymethyl cellulose (CMC) derived from sugar palm fiber, addressing the need for sustainable and eco-friendly electrolyte materials. The BPE films were prepared by incorporating various weight percentages (0, 10, 20, 30, and 40 wt%) of ammonium thiocyanate (NH₄SCN) as a charge carrier via the solution casting technique. The molecular interaction, structural, electrical, and electrochemical properties of the films were characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Electrochemical Impedance Spectroscopy (EIS), Transference Number Measurements (TNM), and Linear Sweep Voltammetry (LSV). The highest ionic conductivity at ambient temperature was achieved at (:6.69times:{10}^{-3}:text{S}:{text{c}text{m}}^{-1}:) with the sample containing 30 wt% NH₄SCN. XRD analysis confirmed the increasing amorphousness of samples with the addition of more NH₄SCN. FTIR and TNM results indicated that proton (H⁺) conduction dominated due to interactions between CMC and the ammonium salt. The LSV analysis showed an electrochemical stability window of approximately 2.2 V, suggesting the potential of this BPE film as an electrolyte in proton batteries. This study’s novelty lies in utilizing sugar palm fiber-derived CMC doped with ammonium thiocyanate, demonstrating enhanced proton conduction in a biodegradable polymer matrix, which has not been extensively explored in prior works.

Gel polymer electrolytes (GPEs) based on mixtures of chitosan and gelatin with acetic acid addition were formulated and studied for electrochemical applications. Chitosan and gelatin with ratio (1:1 v/v %) were used to make the GPEs. Glycerol as plasticizer and formaldehyde as crosslinker were also used in GPEs formulations (S1-S5). Ionic conductivity experiments showed that the electrolyte S4 with 0.75 µL of added acetic acid had the best ionic conductivity of 6.5 × 10⁻³ S·cm⁻¹ at room temperature and 9.8 × 10^− 3 S cm^− 1 at 60 °C. Additionally, a linear conductivity as a function of temperature was seen for every electrolyte under investigation, which was in line with an Arrhenius-type ionic conduction mechanism. The complex dielectric permittivity was used to prove electrode polarization. From the FTIR spectra, we were able to see the changes of the electrolyte structure by considering all new bonds formed between the polymers, acetic acid, glycerol, and formaldehyde. The electrochemical stability of the samples was investigated by cyclic voltammetry, demonstrating that the S4 sample is suitable for use in electrochemical devices, such as battery-type or electrochromic devices. In the end, the LSV analysis revealed that the S4 degraded at ambient temperature and at an applied potential of 2.33 V.

Graphical abstract

Two new silver(I) complexes based on benzimidazole sulfide ligand, [Ag₂(4py-bbs)₂(µ-5-hydroxyisophthalate)]·C₂H₅OH·4H₂O (1) and [Ag₂(4py-bbs)₂(terephthalate)]·2CH₃CN·2H₂O (2) (where 4Py-bbs = bis[1-(pyridin-4-ylmethyl)-benzimidazol-2-ylmethyl]thioether), have been successfully synthesized. Single-crystal structure analysis revealed that although both complexes 1–2 feature binuclear structures, their central silver ions exhibit different coordination environments. The electrochemical sensing performance of the silver complex modified glassy carbon electrodes (1/2-GCE) was investigated using chronoamperometry. The results demonstrate that 1/2-GCE enable the specific detection of H₂O₂, exhibiting a response range of 0.5 µM ~ 4.0 mM, detection limits of 0.39 and 0.41 µM, and sensitivities of 218.59 and 144.37 µA·mM^− 1·cm^− 2, respectively. In addition, the 1- and 2-GCEs both showed good electrocatalytic activity for the hydrogen evolution reaction (HER), featuring positive overpotential (η₁₀: -722 and − 823 mV) and low Tafel slope (b: 196 and 203 mV·dec^− 1). The electrocatalytic activity order for H₂O₂ recognition and HER was 1-GCE > 2-GCE, which depends on the coordination environment of silver(I). This study provides a new thought for designing more efficient electrode materials.

The development of high-performance cathode materials is critical for advancing aqueous zinc-ion batteries (AZIBs) as sustainable energy storage systems. In this work, we report the synthesis and comprehensive characterization of a manganese dioxide–manganese vanadium oxide (MnO₂/MVO) composite as a novel cathode material for AZIBs. The composite was fabricated via a controlled two-step hydrothermal process, resulting in the successful incorporation of MnV₂O₆ into α-MnO₂ nanorod frameworks without compromising phase purity. Detailed structural, morphological, and electrochemical investigations reveal that though the specific surface area of the MnO₂/MVO composite is reduced compared to pristine MnO₂, its broader pore size distribution and enhanced structural stability significantly improve electrochemical performance. The composite exhibits a high reversible capacity of 295.2 mAh g^− 1 at 50 mA g^− 1, superior cycling stability, improved rate capability, and higher Zn²⁺ diffusion coefficients. These enhancements are attributed to the synergistic interaction between the high theoretical capacity of MnO₂ and the structural integrity imparted by MnV₂O₆. This study highlights a promising materials design strategy for overcoming intrinsic limitations of MnO₂-based cathodes and contributes valuable insights into the development of next-generation AZIB technologies.