Ionics最新文献

Microbial fuel cells (MFCs) are potential bioelectrochemical systems for simultaneous wastewater treatment and energy harvesting, but their use is generally restricted by the high cost of proton exchange membranes and biofouling problems. In this research work, an affordable ceramic separator made from Ground Granulated Blast-furnace Slag (GGBS) was developed and coupled with a single-chamber MFC. The GGBS-based ceramic separator offered an antifouling and low-cost substitute for commercial membranes, allowing the effective ion transport and stable operation. To further improve cathodic oxygen reduction reaction (ORR), ZnFe₂O₄ nanoparticles prepared through a sol–gel route were deposited on the cathode surface. The MFC with GGBS separator and ZnFe₂O₄ cathode had a maximum power density of 5.3 W/m³ at 1.0 mg/cm² catalyst loading, a 20% increase over the control. These results illustrate that the GGBS-based ceramic separator is the major innovation for cost and fouling minimization in MFCs, and ZnFe₂O₄ is an added performance improvement, with both presenting a viable method for sustainable wastewater treatment and bioelectricity generation.

Graphical Abstract

Tin dioxide (SnO₂) has gained wide recognition as a potential candidate for high-capacity anode applications in sodium-ion battery systems due to its great advantages in theoretical capacity and costs. However, its practical application is hindered by several critical challenges, including substantial volume expansion during charge/discharge cycles, low electronic conductivity, and sluggish electrochemical reaction kinetics. In contrast, defect engineering offers a viable solution to these limitations. By strategically modifying crystal structures through oxygen vacancy creation, solid solution modification, and elemental doping, the sodium storage performance of SnO₂ anodes can be substantially improved. This review first provides a concise introduction to the challenges facing SnO₂ anodes and the limitations of conventional modification approaches. Subsequently, it systematically examines various approaches to boost the electrochemical behavior of SnO₂ as an anode material. Finally, the review outlines both the potential challenges and promising prospects of employing defect engineering to enhance the performance of SnO₂ as a high-efficiency anode material for sodium storage.

The present work provides a detailed comparison of three deep learning models and their application for SOC: Deep Feedforward Neural Network (FFNN), Long Short-Term Memory (LSTM), and Gated Recurrent Unit (GRU) models under varying thermal conditions. This study aims to understand the practicality of the three advanced neural network architectures in order to determine the most suitable architecture for SOC estimation in EVs in real time. All models were trained using the Adam optimizer and evaluated in terms of training effectiveness, error convergence, and prediction accuracy under varying thermal conditions. The obtained results demonstrate that temperature has a significant impact on the dynamics of the SoC and battery voltage leading to significant nonlinearity and estimation deviations. Among the architectures that were evaluated, the FFNN showed the shortest training time (32 s) highlighting its suitability for lightweight applications. However, it shows poor robustness and high sensitivity to temperature changes. The highest maximum error (26.02%) and a modest RMSE (0.024), confirming the FFNN limited ability to capture sequential SoC dynamics. The GRU provided a good balance between accuracy and computational cost by achieving better convergence stability, increased precision, and smoother estimation behavior with a maximum error and RMSE which does not exceed respectively 8.42% and 0.0212. Across all test conditions, the LSTM network achieved the highest overall performance, with the lowest MSE (1.7700e-05), MAE (0.0032), RMSE (0.0042), and maximum error (1.86%), offering the most precise and thermally consistent estimation. Overall, LSTM stands out as the most powerful and accurate solution, which making it the most suitable candidate for real-time battery management systems in electric vehicles.

The demand for compact, efficient, and sustainable power sources has driven innovation in portable energy electronics, necessitating solutions that are both high-performing and adaptable. This work presents a miniaturized membraneless photocatalytic fuel cell (PFC) fabricated using stereolithography (SLA) 3D printing and employing titanium dioxide (TiO₂)-modified carbon cloth (CC) as the working electrode. The TiO₂ modification enhanced the catalytic activity, surface area, and electrochemical properties of the CC, and the SLA 3D printing enabled precise miniaturization and structural flexibility tailored for wearable applications. The fabricated PFC demonstrated excellent performance under LED light and xenon solar simulation, achieving an open-circuit voltage (OCV) of 848 mV, a maximum power density of 152 µW/cm², and a short-circuit current density of 1.087 mA/cm² while using KOH as electrolyte with a concentration of 0.7 M. The synergy between 3D-printed design versatility and the enhanced properties of TiO₂-modified CC underscores the potential of this approach to deliver reliable, eco-friendly, and scalable energy solutions for portable devices such as PFCs. Consequently, the developed miniaturized PFC provides better power density, making it a more sustainable and renewable clean energy source.

This study explores alkylammonium-based protic ionic liquids (PILs) with varied alkyl chain lengths and hydroxyl group inclusions, focusing on their viability in high-temperature proton exchange membrane fuel cells (PEMFCs). Operating above 100 °C offers potential benefits such as reduced carbon monoxide catalyst poisoning, improved reaction kinetics, and enhanced heat management, leading to greater system efficiency and durability. Conductivity and viscosity measurements from 30 °C to 120 °C show that PILs containing hydroxylated cations like 2-hydroxyethylammonium ([2HEA]⁺) and 2-methyl-2-hydroxyethylammonium ([m-2HEA]⁺) demonstrate superior performance. Conductivities exceeded 10^− 3 S/cm at 60 °C and 10^− 2 S/cm at 90 °C. Higher acidity PILs, such as 2-hydroxyethylammonium acetate ([2HEA][Ac]), exhibited enhanced conductivity due to improved proton transfer mechanisms. Thermal decomposition analysis indicated most PILs decompose above 100 °C, with exceptions like diethylammonium acetate ([DEA][Ac]), which showed anodic and cathodic peaks at higher temperatures due to by-product formation, limiting its applicability at high temperatures. With increasing temperature, a transition from viscosity-dominated to proton hopping mechanisms, like the Grotthuss mechanism, was observed. Hydroxyl groups in cations enhance proton transfer, significantly increasing conductivity at elevated temperatures, while intensified hydrogen-bond networks amplify temperature effects. These findings underscore the potential of hydroxylated PILs in advanced fuel cell technologies, emphasizing the need for balanced viscosity, conductivity, and thermal stability for optimal performance.

Hard carbon is widely regarded as a promising anode material for sodium-ion batteries owing to its high reversible capacity and low operating potential. Nevertheless, achieving an optimal balance between electrochemical performance and cost-effectiveness remains a significant challenge. In this study, spent coffee grounds (SCGs) were employed as a sustainable precursor for the synthesis of hard carbon via a pre-oxidation-assisted high-temperature carbonization process. The influence of pre-oxidation on the structural evolution and sodium storage behavior of the resulting materials was systematically investigated. Experimental results indicate that pre-oxidation effectively introduces abundant oxygen-containing functional groups, suppresses excessive graphitization and structural ordering of carbon microcrystallites, enlarges the interlayer spacing (d₀₀₂), and facilitates the formation of a turbostratic structure with closed micropores. The sample subjected to pre-oxidation at 300 °C followed by carbonization at 1200 °C exhibits superior electrochemical performance, delivering a high reversible specific capacity of 328.49 mAh g^− 1, excellent cycling stability with Coulombic efficiency stabilized at 97–98%, and outstanding rate capability. This work not only presents a novel strategy for the valorization and resource recovery of waste coffee grounds but also underscores the critical role of pre-oxidation in tailoring the microstructure of biomass-derived hard carbons, thereby enhancing their performance in sodium-ion batteries. These findings offer valuable insights for the development of low-cost, sustainable, and high-performance energy storage materials.

Graphical Abstract

The blooming of affordable negative electrodes for supercapacitors and improving their efficiency has recently gained attention in the energy storage. In this regard, transition metal phosphates show great promise as supercapacitor electrode materials. Here, the cobalt iron phosphate and its carbon composite were synthesized using microwave irradiation method. The prepared compounds were subjected to analyse its structural and morphological characteristics via powder X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), Brunauer − Emmett − Teller (BET). XRD analysis revealed that the incorporation of carbon nanofibers disrupts the crystallization of cobalt iron phosphate, resulting in nanocomposites that predominantly exhibit an amorphous structure. The chemical state and environment of the elements present in the 2.5 wt% of carbon nanofiber is blended composite is examined using X-ray photoelectron spectroscopy technique. The pristine cobalt iron phosphate exhibits a quasi-spherical nanostructure morphology, which is retained in the composites as well. However, the particle size is noticeably reduced upon the addition of carbon nanofibers, highlighting their effectiveness in minimizing aggregation and controlling particle growth. Furthermore, electrochemical analysis performed using a three-electrode configuration reveals prominent redox peaks, indicating that the prepared electrode materials store energy primarily through redox reactions. A maximum specific capacity of 553 C g^− 1 at a current density of 1 mA cm^− 2 was achieved for the cobalt iron phosphate composite containing 2.5 wt% carbon nanofibers. Additionally, the material demonstrated excellent cycling stability, achieving a remarkable 116% capacity retention even after 2000 GCD cycles. The results underscore the synergistic effect of carbon support and microwave synthesis in enhancing the electrochemical performance of cobalt iron phosphate, making it a strong candidate for future asymmetric supercapacitor devices.

PPy/CQDs/V₂O₅ (PCV) composite electrodes were synthesized through in situ oxidative polymerization of pyrrole, utilizing FeCl₃ as the oxidizing agent. By systematically adjusting the weight ratio of V₂O₅ while keeping the amounts of PPy and CQD constant, a series of PPy/CQDs/V₂O₅ (PCV) composites was produced. These composites consist of polypyrrole (PPy), polystyrene sulphonic acid (PPS)-activated carbon quantum dots (CQDs), and vanadium pentoxide (V₂O₅). Among these, PCV0.6 (PPy + CQDs (0.4 g) + V₂O₅ (0.6 g)) exhibited exceptional electrochemical performance, achieving a high specific capacitance of 1128.2 F/g at a scan rate of 2 mV/s and retaining 80.1% of its initial capacitance after 10,000 charge-discharge cycles. Furthermore, at a current density of 0.5 A/g, the device achieved an impressive energy density of 122.6 Wh/kg with a corresponding power density of 250.1 W/kg. Even at a higher current density of 2.5 A/g, the device sustained a considerable energy density of 48.8 Wh/kg while delivering a power density of 1252.7 W/kg. To demonstrate practical feasibility, an asymmetric supercapacitor device based on PCV0.6 (PPy + CQDs (0.4 g) + V₂O₅ (0.6 g)) was fabricated. This device successfully powered a 1 V light-emitting diode (LED) for approximately 2.48 min after a 5-minute charging cycle, underscoring its potential for real-world energy storage applications.

Antibiotic resistant microbes and toxic antibiotic effluents pose a hazard to world health. Designing and constructing of a heterostructure materials for the improvement of the photocatalytic performance through redox ability requires a considerable effort while addressing the removal of antibiotics from waste water. To address this issue, a direct Z-scheme heterostructure composite ZIF-67/Bi₂O₃ has been developed by using the hydrothermal technique. The optimized composite ZIF-67/Bi₂O₃ has been utilized for the effective photo degradation of doxycycline under visible light. The composite was characterised with various techniques such as XRD, FTIR, XPS, SEM, UV-DRS, and electrochemical parameters. Electrochemical impedance spectroscopy (EIS) evaluates charge transfer stability and efficiency, whereas Cyclic voltammetry (CV) provides information on surface electrochemical activity and redox behaviour. According to EIS, the ZIF-67/Bi₂O₃ nanocomposite had the lowest charge transfer resistance (R_ct) of all the materials examined. The ZIF-67/Bi₂O₃ composite shows the best performance towards the doxycycline degradation due to the better channelization of charge carriers through of Z-scheme mechanistic pathway. The quicker electron transport and more effective charge separation at the electrode-electrolyte interface promotes the photocatalytic transformation of doxycycline to different by-products and finally mineralized to CO₂ and H₂O.The sustainability of ZIF-67/Bi₂O₃ composite is demonstrated by testing its recyclability for five consecutive cycles.