Search Results (2,677)

The development of high-performance supercapacitor electrodes is crucial to meet the increasing demand for efficient and sustainable energy storage systems. Cobalt oxide (Co₃O₄), with its high theoretical capacitance, is a promising electrode material, but its practical application is hindered by poor conductivity limitations and structural instability during cycling. In this work, lanthanum La³⁺-doped Co₃O₄ nanocubes were synthesized via a hydrothermal approach to tailor their structural and electrochemical properties. Different doping concentrations (1, 3, and 5%) were introduced to investigate their influence systematically. X-ray diffraction confirmed the retention of the spinel phase with clear evidence of La³⁺ incorporation into the Co₃O₄ lattice. Also, Raman spectroscopy validated the structural integrity through characteristic Co-O vibrational modes. Scanning electron microscopy analysis revealed uniform cubic morphologies across all samples. The formation of the cubic spinel structure of 1% La³⁺-doped Co₃O₄ are confirmed from XPS and TEM studies. Electrochemical evaluation in a 3 M KOH electrolyte demonstrated that 1% La³⁺-doped Co₃O₄ nanocubes delivered the highest performance, achieving a specific capacitance of 1312 F g⁻¹ at 1 A g⁻¹ and maintaining a 79.8% capacitance retention and a 97.12% Coulombic efficiency over 10,000 cycles at 5 Ag⁻¹. It can be demonstrated that La³⁺ doping is an effective strategy to enhance the charge storage capability and cycling stability of Co₃O₄, offering valuable insights for the rational design of next-generation supercapacitor electrodes. Full article

Traditional liquid electrolyte batteries face safety concerns such as leakage and flammability, while further optimization has reached a bottleneck. Solid electrolytes are therefore considered a promising solution. Here, a PEO–LiTFSI–LATP (PELT) composite electrolyte was developed by incorporating nanosized Li_1.3Al_0.3Ti_1.7(PO₄)₃ fillers into a polyethylene oxide matrix, effectively reducing crystallinity, enhancing mechanical robustness, and providing additional Li⁺ transport channels. The PELT electrolyte exhibited an electrochemical stability window of 4.9 V, an ionic conductivity of 1.2 × 10⁻⁴ S·cm⁻¹ at 60 °C, and a Li⁺ transference number (tLi+) of 0.46, supporting stable Li plating/stripping for over 600 h in symmetric batteries. More importantly, to address poor electrode–electrolyte contact in conventional layered cells, we proposed an integrated electrode–electrolyte architecture by in situ coating the PELT precursor directly onto LiFePO₄ cathodes. This design minimized interfacial impedance, improved ion transport, and enhanced electrochemical stability. The integrated PELT/LFP battery retained 74% of its capacity after 200 cycles at 1 A·g⁻¹ and showed superior rate capability compared with sandwich-type batteries. These results highlight that coupling LATP-enhanced polymer electrolytes with an integrated architecture is a promising pathway toward high-safety, high-performance solid-state lithium-ion batteries. Full article

MXenes, a rapidly emerging family of two-dimensional transition metal carbides and nitrides, have attracted considerable attention in recent years for their potential in next-generation energy storage technologies. In solid-state batteries (SSBs), they combine metallic-level conductivity (>10³ S cm⁻¹), adjustable surface terminations, and mechanical resilience, which makes them suitable for diverse functions within the cell architecture. Current studies have shown that MXene-based anodes can deliver reversible lithium storage with Coulombic efficiencies approaching ~98% over 500 cycles, while their use as conductive additives in cathodes significantly improves electron transport and rate capability. As interfacial layers or structural scaffolds, MXenes effectively buffer volume fluctuations and suppress lithium dendrite growth, contributing to extended cycle life. In solid polymer and composite electrolytes, MXene fillers have been reported to increase Li⁺ conductivity to the 10⁻³–10⁻² S cm⁻¹ range and enhance Li⁺ transference numbers (up to ~0.76), thereby improving both ionic transport and mechanical stability. Beyond established Ti-based systems, double transition metal MXenes (e.g., Mo₂TiC₂, Mo₂Ti₂C₃) and hybrid heterostructures offer expanded opportunities for tailoring interfacial chemistry and optimizing energy density. Despite these advances, large-scale deployment remains constrained by high synthesis costs (often exceeding USD 200–400 kg⁻¹ for Ti₃C₂T_x at lab scale), restacking effects, and stability concerns, highlighting the need for greener etching processes, robust quality control, and integration with existing gigafactory production lines. Addressing these challenges will be crucial for enabling MXene-based SSBs to transition from laboratory prototypes to commercially viable, safe, and high-performance energy storage systems. Beyond summarizing performance, this review elucidates the mechanistic roles of MXenes in SSBs—linking lithiophilicity, field homogenization, and interphase formation to dendrite suppression at Li|SSE interfaces, and termination-assisted salt dissociation, segmental-motion facilitation, and MWS polarization to enhanced electrolyte conductivity—thereby providing a clear design rationale for practical implementation. Full article

This paper provides a systematic review of the latest advancements in metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) for electrocatalytic carbon dioxide reduction. Both materials exhibit high specific surface areas, tunable pore structures, and abundant active sites. MOFs enhance CO₂ conversion efficiency through improved conductivity, optimized stability, and selective regulation—including bimetallic synergy, pulse potential strategies, and tandem catalysis. COFs achieve efficient catalysis through precise design of single or multi-metal active sites, optimization of framework conjugation, and photo/electro-synergistic systems. Both types of materials demonstrate excellent selectivity toward high-value-added products (CO, formic acid, C₂⁺ hydrocarbons), but they still face challenges such as insufficient stability, short operational lifespan, high scaling-up costs, and poor electrolyte compatibility. Future research should integrate in situ characterization with machine learning to deepen mechanistic understanding and advance practical applications. Full article

NASICON-type Li_1+XFe_XTi_2-X(PO₄)₃ (x = 0.1, 0.3, 0.4) solid electrolytes for all-solid-state Li-ion batteries were synthesized using a sol–gel method. This study investigated the impact of substituting Fe³⁺ (0.645 Å), a trivalent cation, for Ti⁴⁺ (0.605 Å) on ionic conductivity. Li_1+XFe_XTi_2-X(PO₄)₃ samples, subjected to various sintering temperatures, were characterized using TG-DTA, XRD with Rietveld refinement, XPS, FE-SEM, and AC impedance to evaluate composition, crystal structure, fracture-surface morphology, densification, and ionic conductivity. XRD analysis confirmed the formation of single-crystalline NASICON-type Li_1+XFe_XTi_2-X(PO₄)₃ at all sintering temperatures. However, impurities in the secondary phase emerged owing to the high sintering temperature above 1000 °C and increased Fe content. Sintered density increased with the densification of Li_1+XFe_XTi_2-X(PO₄)₃, as evidenced by FE-SEM observations of sharper edges of larger quasi-cubic grains at elevated sintering temperatures. At 1000 °C, with Fe content exceeding 0.4, grain coarsening resulted in additional grain boundaries and internal cracks, thereby reducing the sintered density. Li_1.3Fe_0.3Ti_1.7(PO₄)₃ sintered at 900 °C exhibited the highest density among the other conditions and achieved the maximum total ionic conductivity of 1.51 × 10⁻⁴ S/cm at room temperature, with the lowest activation energy for Li-ion transport at 0.37 eV. In contrast, Li_1.4Fe_0.4Ti_1.6(PO₄)₃ sintered at 1000 °C demonstrated reduced ionic conductivity owing to increased complex impedance associated with secondary phases and grain crack formation. Full article

In this work, a novel solid polymer electrolyte with a disordered structure has been designed, combining polyethylene glycol (PEG) as the flexible segments and hexamethylene diisocyanate (HDI) as the rigid segments. The synthesis was realized by alternating flexible PEG with rigid HDI through a peptide bond (–CO–NH–), which disrupts the ordered structures of PEG, generating electron-deficient Lewis acid groups. The pathbreaking introduction of HDI blocks not only bridges links between the PEG molecules but also generates electron-deficient Lewis acid groups. Therefore, the original ordered structures of PEG are disrupted by both the alternating chains between PEG and HDI and the Lewis acid groups. As a result, the PEG_H/L4000 electrolytes (PEG molecular weight of 4000) exhibit a strong anion-capture ability that decreases the crystallinity of polymers, which further achieves a high ionic conductivity close to 10⁻³ S·cm⁻¹ with the lithium-ion transference numbers up to 0.88. The symmetric Li|PEG_H/L4000|Li cells maintain a low and stable voltage polarization for more than 800 h at 0.1 mA·cm⁻². Furthermore, the LiFePO₄|PEG_H/L4000|Li all-solid-state cells perform well both in cycling and rate performances. The design of polymer disordered structures for polymer electrolytes provides a new thought for manufacturing all-solid-state lithium-ion batteries with high safety as well as long life. Full article

The pursuit of sustainable and environmentally benign energy storage solutions has propelled significant interest in organic batteries, which utilize redox-active organic compounds as electrode materials. A pivotal component in determining their electrochemical performance, safety, and long-term stability is the electrolyte. Polymer-based electrolytes (PBEs) have emerged as promising candidates owing to their intrinsic advantages, such as enhanced thermal stability, mechanical integrity, and the mitigation of leakage and flammability risks associated with conventional liquid electrolytes. Unlike previous reviews that broadly cover solid electrolytes, this review specifically focuses on the unique developments of polymer-based electrolytes tailored for organic batteries over the past few years. This review presents a comprehensive overview of the recent progress in PBEs specifically designed for organic battery systems. It systematically examines various categories, including solid polymer electrolytes (SPEs), valued for their structural simplicity and stability; gel polymer electrolytes (GPEs), noted for their high ionic conductivity and processability; and polymer-inorganic composite electrolytes, which synergistically integrate the mechanical flexibility of polymers with the ionic conductivity of inorganic fillers. Additionally, the review delves into the latest advancements in ionogels and poly(ionic liquid) electrolytes, highlighting their potential to overcome existing limitations and enable next-generation battery performance. The article concludes with a critical discussion on prevailing challenges and prospective research directions, emphasizing the importance of advanced material design, interfacial engineering, and sustainable synthesis approaches to facilitate the practical realization of high-performance organic batteries. Full article

Sodium metal batteries (SMBs) with ceramic solid electrolytes offer a promising route to improve the energy density of conventional Na-ion batteries (SIBs). Silicate-based ceramics have recently gained attention for their favourable properties, including better ionic conduction and wider stability windows. In this study, 10% Pr³⁺ and Nd³⁺ were doped into sodium gadolinium silicate ceramics to examine the effects on phase purity, ionic conductivity, and interfacial compatibility with sodium metal anodes. The materials were synthesized via solid-state methods and sintered at 950–1075 °C to study the impact of sintering temperature on densification and microstructure. Na₅Gd_0.9Pr_0.1Si₄O₁₂ (NGPS) and Na₅Gd_0.9Nd_0.1Si₄O₁₂ (NGNS) sintered at 1075 °C showed the highest room temperature total ionic conductivities of 1.64 and 1.74 mS cm⁻¹, respectively. The highest critical current density of 0.5 mA cm⁻² is achieved with a low interfacial area-specific resistance of 29.47 Ω cm² for NGPS and 22.88 Ω cm² for NGNS after Na plating/stripping experiments. These results highlight how doping enhances phase purity, ionic conductivity, and interfacial stability of silicates with Na metal anodes. Full article

Carbon nanorods have been synthesized from acetylene and steam using europium oxide nanorods as a template. The resulting carbon exhibits a high conductivity of 4.66 × 10⁵ S/m and a surface area of 1226 m²/g. The Eu₂O₃ was partially or completely washed from the carbon, creating hollow nanorods. Hybrid supercapacitors were fabricated where the Eu₂O₃ contributes a redox pseudocapacitance. A gravimetric capacitance of 501.2 F/g for the hybrid cell and 202 F/g for the carbon-only cell was measured at 1 A/g using 1 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in propylene carbonate as an electrolyte. The hybrid supercapacitor exhibited an excellent energy density of 108 Wh/kg at 1 A/g compared to 43 Wh/g at 1 A/g for the carbon-only supercapacitor. Full article

In wastewater treatment, sludge is generated during both the primary and secondary sedimentation processes. With the growing volume of wastewater, sludge production has increased accordingly. Prior to subsequent treatment or disposal, sludge dewatering is a critical step to reduce volume and improve treatment efficiency. The primary challenge lies in the removal of bonded water within the extracellular polymeric substances (EPSs) and the microorganism cells. In this study, electrochemical pretreatment was employed to improve sludge dewatering performance. The optimal electrochemical treatment was achieved at an electrode spacing of 2 cm, a stirring speed of 500 rpm, and an electrolyte (1 M calcium chloride, CaCl₂) dosage of 3 mL for 50 min. Subsequently, flocculation was conducted. Compared with the widely used polyacrylamide (PAM), polydimethyldiallylammonium chloride (PDMDAAC) achieved superior dewatering performance with less than half the dosage required. Under the combined treatment, the final moisture content of the sludge cake was reduced to 53.2%. These findings indicate that the combination of Fe/Ti-based electrochemical pretreatment and flocculation process is a promising and efficient strategy for deep sludge dewatering. Full article

The vibration properties of materials play a role in their conduction of electric charges. Ionic conductors such as electrodes and solid electrolytes are also relevant in this respect. The vibration properties are typically assessed with infrared and Raman spectroscopy, and inelastic neutron scattering, which all allow for the derivation of the phonon density of states (PDOS) in part of a full portion of the Brioullin zone. Nuclear resonant vibration spectroscopy (NRVS) is a novel method that produces the element-specific PDOS from Mössbauer-active isotopes in a compound. We employed NRVS operando on a pouch cell battery containing a Li⁵⁷FePO₄ electrode, and thus could derive the PDOS of the ⁵⁷Fe in the electrode during charging and discharging. The spectra reveal reversible vibrational changes associated with the two-phase conversion between LiFePO₄ and FePO₄, as well as signatures of metastable intermediate states. We demonstrate how the NRVS data can be used to tune the atomistic simulations to accurately reconstruct the full vibration structures of the battery materials in operando conditions. Unlike optical techniques, NRVS provides bulk-sensitive, element-specific access to the full phonon spectrum under realistic operando conditions. These results establish NRVS as a powerful method to probe lattice dynamics in working batteries and to advance the understanding of ion transport and phase transformation mechanisms in electrode materials. Full article

Background/Objectives: Severe acute pancreatitis (SAP) carries substantial morbidity and resource burden, and early risk stratification remains challenging with conventional scores that require serial observations. The aim of this study was to develop and compare supervised machine-learning (ML) pipelines—integrating feature selection and SHAP-based explainability—for early prediction of SAP at emergency department (ED) presentation. Methods: This retrospective, single-center cohort was conducted in a tertiary-care ED between 1 January 2022 and 1 January 2025. Adult patients with acute pancreatitis were identified from electronic records; SAP was classified per the Revised Atlanta criteria (persistent organ failure ≥ 48 h). Six feature-selection methods (univariate AUROC filter, RFE, mRMR, LASSO, elastic net, Boruta) were paired with six classifiers (kNN, elastic-net logistic regression, MARS, random forest, SVM-RBF, XGBoost) to yield 36 pipelines. Discrimination, calibration, and error metrics were estimated with bootstrapping; SHAP was used for model interpretability. Results: Of 743 patients (non-SAP 676; SAP 67), SAP prevalence was 9.0%. Compared with non-SAP, SAP patients more often had hypertension (38.8% vs. 27.1%) and malignancy (19.4% vs. 7.2%); they presented with lower GCS, higher heart and respiratory rates, lower systolic blood pressure, and more frequent peripancreatic fluid (31.3% vs. 16.9%) and pleural effusion (43.3% vs. 17.5%). Albumin was lower by 4.18 g/L, with broader renal–electrolyte and inflammatory derangements. Across the best-performing models, AUROC spanned 0.750–0.826; the top pipeline (RFE–RF features + kNN) reached 0.826, while random-forest-based pipelines showed favorable calibration. SHAP confirmed clinically plausible contributions from routinely available variables. Conclusions: In this study, integrating feature selection with ML produced accurate and interpretable early prediction of SAP using data available at ED arrival. The approach highlights actionable predictors and may support earlier triage and resource allocation; external validation is warranted. Full article

Water treatment systems in swimming ponds support the natural self-cleaning capabilities of water based on the functions of repository macrophytes in their regeneration zone and the regulation of the internal metabolism of the reservoirs. As part of the project, a functional modular filtration chamber with system multiplication capabilities was designed and created. This element is dedicated to water treatment systems in natural swimming ponds. The prototype system consisted of modular filtration chambers and pump sections, as well as equipment adapted to the conditions prevailing in the eco-pool. An innovative solution for selective shutdown of the filtration chamber without closing the circulation circuit was also used, which forms the basis of a patent application. A verified high-performance adsorbent, Rockfos^® modified limestone, was used in the filtration chamber. In order to determine the effective filtration rate for three small test ponds with different flow rates (5 m/h, 10 m/h and 15 m/h), the selected physicochemical parameters of water (temperature, pH, electrolytical conductivity, oxygen saturation, total hardness, nitrites, nitrates, and total phosphorus, including adsorption efficiency and bed absorption capacity) were researched before and after filtration. Tests were also carried out on the composition of fecal bacteria and phyto- and zooplankton. Based on high effective phosphorus filtration efficiency of 32.65% during the operation of the bed, the following were determined: no exceedances of the standards for the tested parameters in relation to the German standards for eco-pools (FLL—Forschungsgesellschaft Landschaftsentwicklung Landschaftsbau e. V., 2011); lower number of fecal pathogens (on average 393—coliform bacteria; 74—Escherichia coli; 34—fecal enterococci, most probably number/100 mL); the lowest share of problematic cyanobacteria in phytoplankton (<250,000 individuals/dm³ in number and <0.05 µg/dm³—biomass); low chlorophyll a content (2.2 µg/dm³—oligotrophy) and the presence of more favorable smaller forms of zooplankton, an effective filtration speed of 5 m/h. This velocity was recommended in the FLL standards for swimming ponds, which were adopted in this study as a reference for rapid filters. In testing the functional efficiency of a dedicated filtration system for a Type II test pond (50 m²—area and 33 m³—capacity), at a filtration rate of 5 m/h, an average effective phosphorus adsorption efficiency of 18.28–53.98% was observed under the bed work-in-progress conditions. Analyses of other physicochemical water parameters, with appropriate calculations and statistical tests, indicated progressive functional efficiency of the system under bathing conditions. Full article

In conventional lithium-ion batteries (LIBs), active lithium loss during solid electrolyte interphase (SEI) formation reduces coulombic efficiency and energy density. Cathode pre-lithiation can effectively compensate for this irreversible lithium consumption. To address limitations of conventional pre-lithiation agents—such as complex synthesis and air instability—a Ketjen black-coated lithium oxalate nanocomposite (Li₂C₂O₄@KB) using high-energy ball milling and spray drying was developed. This composite leverages the advantages of Li₂C₂O₄, including a mild decomposition potential (4.26 V vs. Li⁺/Li), high theoretical lithium compensation capacity (525 mAh·g⁻¹), and environmentally benign decomposition products, and significantly improves electronic conductivity and reduces particle size. When incorporated in NCM622 full cells, the initial capacity is increased by 18.21 mAh·g⁻¹ at 0.3 C, with a 29.22% enhancement in capacity retention after 50 cycles at 0.3 C. At 1 C, the initial capacity is higher by 15.79 mAh·g⁻¹, accompanied with a 7.72% improvement in retention after 100 cycles. The Li₂C₂O₄@KB composite exhibits great promise as a practical and efficient cathode pre-lithiation additive for next-generation high-energy-density LIBs. Full article

This work presents a theoretical investigation of ionic conductivity in cubic zirconia (c-ZrO₂) doped with magnesium, using density functional theory (DFT) with the hybrid B3LYP functional as implemented in the CRYSTAL23 software package. It was found that the spatial arrangement of magnesium atoms and oxygen vacancies significantly affects the energy barriers for oxygen ion migration. Configurations with magnesium located along and outside the migration path were analyzed. The results show that when Mg²⁺ is positioned along the migration trajectory and near an oxygen vacancy, stable defect complexes are formed with minimal migration barriers ranging from 0.96 to 1.32 eV. An increased number of Mg atoms can lead to a further reduction in the barrier, although in certain configurations the barriers increase up to 3.0–4.6 eV. When doping occurs outside the migration path, the energy profile remains symmetric and moderate (0.9–1.1 eV), indicating only a weak background influence. These findings highlight the critical role of coordinated distribution of Mg atoms and oxygen vacancies along the migration pathway in forming efficient ion-conducting channels. This insight offers potential for designing high-performance zirconia-based electrolytes for solid oxide fuel cells and sensor applications. Full article