Ionics最新文献

Microbial fuel cells (MFCs) generate electricity from organic substrates by breaking them into simpler compounds. While primarily acetate is considered as substrate due to its highest coulombic efficiency, other complex organic substrates needs to be utilized to improve the practicality of MFCs. However, as the coulombic efficiency of other substrates is low, addition of mediators improves the cell performance. In this study, Ping – Pong mechanism is considered to optimize the performance of the MFCs. The effect of substrate and mediator concentration on the operating parameters and cell output is modeled. The model is validated with the experimental data taken from the literature and found to compare well.

Fe₃O₄ has broad development as an anode material for lithium ion batteries due to its high specific capacity and low cost. The low electrical conductivity and huge volume variation during cycle processes hinder its practicability. To enhance the electrochemical performance, the N-doped carbon derived from urea and glucose as a carrier, the novel Fe₃O₄ loaded on the porous N-doped carbon sphere structure was explored. The samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy (XPS). The results showed that the Fe₃O₄ loaded on the porous N-doped carbon composite material exhibited a porous spherical structure with a specific surface area of 131.32 m² g^− 1. The initial reversible capacity of the composite material was 1694.2 mAh g^− 1 at 500 mA g^− 1, and 813.7 mAh g^− 1 after 200 cycles. The reversible capacity of composite material are 710 mAh g^− 1, 601 mAh g^− 1, 470 mAh g^− 1, 385 mAh g^− 1, and 365 mAh g^− 1 at current densities of 100 mA g^− 1, 200 mA g^− 1, 500 mA g^− 1, 800 mA g^− 1, and 1000 mA g^− 1, respectively. The specific capacity is 615 mAh g^− 1 when the current density is tuned back to 100 mA g^− 1. The abundant pore volume facilitates lithium-ion diffusion and improves lithium storage capacity. Its structure is conducive to controlling volume expansion, improving conductivity and electrochemical performance.

The synergistic modulation of both the surface electronic configuration and micromorphology of the catalyst is crucial for its electrochemical hydrogen evolution activity. This research successfully developed an efficient Ru-WS₂ NS/CC electrocatalyst for the hydrogen evolution reaction (HER) using a simple two-step strategy involving a solvothermal reaction followed by chemical vapor deposition. The catalyst exhibits excellent electrocatalytic activity and remarkable stability in acidic electrolyte, demonstrating an overpotential of 128.8 mV (at 10 mA cm^− 2), a Tafel slope of 58.7 mV dec^− 1, and a low charge transfer resistance of only 3.8 Ω, while maintaining high catalytic activity for at least 24 h under acidic conditions. The enhanced HER performance of the Ru-WS₂ NS/CC catalyst is attributed to two main factors: first, the strong electronic interaction induced by Ru doping, which improves the intrinsic electrocatalytic activity; second, the uniform and thin nanosheet morphology of WS₂ provides a highly developed surface area that facilitates hydrogen adsorption and desorption. Density functional theory (DFT) simulations further indicate that introducing Ruthenium (Ru) dopants substantially lowers the Gibbs free energy (ΔG_H*) associated with hydrogen adsorption on the catalyst. Analysis of charge density differences corroborates that such doping strategy efficiently tailors the electronic configuration of the WS₂ support, thereby optimizing its interfacial characteristics. This work proposes an effective electronic structure modulation strategy for developing three-dimensional materials into high-efficiency hydrogen evolution electrocatalysts.

Amorphous oxide glasses with compositions (5-x)Li₂O-5Al₂O₃-75B₂O₃15MgF₂-xGd₂O₃where x = 0.0, 0.2, 0.4, and 0.6 mol% were synthesized via melt-quenching technique. The structural characterizations of fresh samples are studied using measured XRD and IR spectra. Furthermore, in Gd free sample the deconvoluted IR showed that BO₄ is the dominant. Moreover, at higher doping levels of Gd resulted in an enhancement of the intensity of the transformed BO₄ into BO₃. The measured dc conductivity showed that the free sample of Gd has the lowest conductivity. As the doping level increased to 0.2 mol%, the dc conductivity increased many orders of magnitude This phenomenon is attributed to the high polarizability of Gd³⁺ over Li⁺. The present study focused mainly on the correlation between Gd³⁺ content and the electrical conductivity behavior. AC conductivity (σ_ac) was measured at frequencies ranging from 100 Hz to 5 MHz and temperatures ranging from 293 to 373 K. The frequency-dependent data were analyzed using Jonscher’s power law (σ_ac ∝ ωˢ) and fitted with the Almond-West formalism to extract the frequency exponent (s) and hopping frequency (ω_H). Among the various conduction models, the Overlapping Large Polaron Tunneling (OLPT) provided the most suitable description of the conduction mechanism. An examination of structural parameters including density, molar volume, average B–B separation, and non-bridging oxygen concentration, was undertaken to elucidate the underlying mechanisms. Introduction of Gd³⁺ ions in the structural matrix of LAB contribute to the formation of localized states and enhance ionicity and ionic transport.

Sodium ions and lithium ions belong to the same main group, share similar chemical properties, and are low-cost, making sodium-ion batteries (SIBs) a promising supplement to lithium-ion batteries (LIBs). Among the various anode materials for sodium-ion batteries, anthracite has attracted much attention due to its low price and carbon content exceeding 90%. Although significant progress has been made in the research of hard carbon derived from anthracite-based carbon materials, the reversible capacity and initial Coulombic efficiency (ICE) of anthracite-based soft carbon are still not satisfactory. In this study, anthracite is used as a raw material, and the interlayer spacing is regulated through thermal treatment. This results in a relatively high capacity of 304.4 mAh g^-1 and an initial Coulombic efficiency (ICE) of 89.3%. Low-cost anthracite coal, low-cost processes, and high initial Coulombic efficiency—these outstanding performance characteristics meet the requirements of practical applications and lay the foundation for the large-scale industrial production of low-cost, high-performance sodium-ion batteries for energy storage.

The practical application of lithium metal batteries is hindered by the heterogeneous solid-electrolyte interphase (SEI), which undergoes repeated cracking and reconstruction during cycling, thereby exacerbating lithium dendrite growth. To address this issue, we propose an in-situ reconstruction strategy for the SEI layer by introducing the functional additive 1,3,5-trioxane (TO), which helps to homogenize lithium transport and enhance mechanical stability. By participating in the Li⁺ solvation structure, TO facilitates the formation of a homogeneous and mechanically robust SEI, which preferentially promotes the formation of a polyoxymethylene (POM) phase and enriches LiF content within the SEI. This tailored interface significantly improves the uniformity of lithium deposition and interfacial compatibility. In coin cells employing a high-loading LiNi_0.90Co_0.05Mn_0.05O₂ cathode (7.37 mg cm^− 2) and an ultrathin lithium anode (50 μm), the TO-modified electrolyte enables a capacity retention of 73.1% after 200 cycles at 0.5 C, substantially outperforming the conventional electrolyte that retained only 25.9%. These results demonstrate the promising potential of this electrolyte design for high-energy-density lithium metal batteries.

An accurate evaluation of the state of charge (SOC) for lithium-ion batteries is crucial for electric vehicles. However, dynamic temperature variations significantly impact both battery model parameters and available capacity, leading to cumulative errors in existing methods. To address this, a novel dual time-scale framework is proposed. This temperature-adaptive SOC estimation technique utilizes a second-order RC equivalent circuit model (ECM). First, a mapping relationship among SOC, open-circuit voltage (OCV), and temperature was established. Subsequently, a hybrid particle swarm optimization and Levenberg-Marquardt (PSO-LM) algorithm was employed to identify ECM parameters at different temperatures. Moreover, capacity tests under varying temperatures and discharge rates were conducted to quantify variations in available capacity. The dual time-scale framework implements microscale updates for ECM parameters and SOC via adaptive filtering, and macroscale updates for battery available capacity. Experimental results demonstrate that under varying temperatures, the proposed method achieves a mean absolute error below 1% and a root mean square error below 1.6%, significantly outperforming the traditional fixed-capacity cubature Kalman filter (CKF). This study provides a comprehensive solution for practical SOC estimation, thereby enhancing the dependability and performance of battery management systems.

Core-shell structure Fe₂O₃@C composite by utilizing the iron concentrate leachate with a selective chemical precipitation method and illustrate its great potential as a high-performance anode material of lithium-ion batteries (LIBs). The Fe₂O₃@C composite exhibits superior cyclic performance (723.08 mA h g^− 1 over 300 cycles at 1 A g^− 1) and high-rate capability (322.01 mA h g^− 1 even at a high current density of 5 A g^− 1) in a half cell. The excellent performance of the Fe₂O₃@C can be attributed to particles contain abundant internal voids, which facilitates the infiltration of the electrolyte and alleviates the volume change of electrode material, thereby enhancing the electrochemical performance of the material. Due to the unique core-shell structure nanostructure, Fe₂O₃@C composite shows significant pseudocapacitive behavior during discharge/charge processes, which partially accounts for the excellent lithium-ion storage performance.