Search Results (60)

This study presents the synthesis and ball-milling modification of titanite (CaTiSiO₅) powders to enhance the thermal stability and performance of polypropylene (PP) separators for lithium-ion batteries (LIBs). CaTiSiO₅ was synthesized using a ceramic route, and the experimental design varied the milling cycles and sphere sizes. Characterization techniques, including scanning electron microscopy, X-ray diffraction, Fourier-transform infra-red spectroscopy, surface area analysis, thermal analysis, and electrochemical tests, confirmed the production of high-purity monoclinic CaTiSiO₅. Ball milling effectively reduced the particle and crystallite sizes while increasing the specific surface area, total pore volume, double-layer capacitance, and ionic conductivity, while also reducing the cell resistance. Coating PP separators with the modified CaTiSiO₅ significantly improved their thermal stability and enhanced their electrochemical properties, including the electron transfer rate and Coulombic efficiency. These findings demonstrate the potential of ball-milled CaTiSiO₅ as a valuable material for developing safer and more efficient LIBs. Full article

A ceramic anode made of Sb-doped SnO₂ and coated with a photoactive BiPO₄ layer was tested for the (photo)electrochemical oxidation of three commonly used pharmaceuticals: atenolol, ibuprofen, and norfloxacin. Light-pulsed chronoamperometry showed that the photoanode responded immediately to illumination. The application of light and current enhanced degradation for all compounds when treated separately. Ibuprofen and norfloxacin exhibited higher degradation than mineralization, which demonstrates their persistent nature. Electric current was essential to achieve efficient degradation and mineralization, demonstrating the effectiveness of the electrochemical approach. For multicomponent mixtures, applying light resulted in higher mineralization compared to dark conditions at low operation currents (0.2 A). At higher currents (0.4–0.8 A), the contribution of light was partially masked by the enhanced electrochemical production of hydroxyl radicals. The analysis of individual compounds within the mixture revealed significant improvements in degradation under light exposure. Overall, these results demonstrate the potential of the Sb-doped SnO₂ ceramic photoanode as a cost-effective and promising alternative to commercial materials for treating pharmaceutical contaminants. Full article

In this work, a carrier-free photoacoustic spectroscopy system is developed for the detection of trace acetylene gas in insulating oil. The photoacoustic cell was integrated with an oil–gas separator, allowing dissolved gases in oil to be introduced into the cell through free diffusion. The oil–gas separator is a custom-fabricated AF2400-coated ceramic membrane, and its spin-coating process was carefully designed to enable rapid oil–gas separation and achieve high film flatness. Using a resonant photoacoustic cell and a low-noise lock-in amplifier, the sensitivity of the system was improved to 6.90 mV/ppm, with a repeatability error less than 1.65%. Calibration experiments demonstrated that continuous detection of dissolved gas in oil could be achieved, with a response time T₉₀ of less than 72.5 min. Compared to traditional photoacoustic spectroscopy, the continuous measurement capability of this method is expected to enable earlier fault diagnosis, thus having greater potential in industrial fields. Full article

The primary objective of this research is to simplify and make the industrial manufacturing process of coated maraging steels more economical by combining the advantages of additive manufacturing with simultaneous bulk (aging) and surface (nitriding) treatment in an effective manner. With this aim, preliminary experiments were performed that demonstrated the hardness (and related microstructure) of an as-built MS1 maraging steel, produced by selective laser melting (SLM), is comparable to that of the bulk maraging steel products treated by conventional solution annealing. The direct aging of the solution-annealed and as-built 3D printed maraging steel resulted in similar hardness, indicating that the kinetics of the precipitation hardening process are identical for the steel in both conditions. This assumption was strengthened by a thermodynamic analysis of the kinetics and determination of the activation energy for precipitation hardening using Differential Scanning Calorimetry (DSC) measurements. Industrial target experiments were performed on duplex-coated SLM-printed MS1 steel specimens, which were simultaneously aged and salt-bath nitrided, followed by PVD coating with three different ceramic layers: DLC, CrN, and TiN. For reference, similar duplex-coated samples were used, featuring a bulk Böhler W720 maraging steel substrate that was solution annealed, precipitation hardened, and salt-bath nitrided in separate steps, following conventional procedures. The technological parameters (temperature and time) of the simultaneous nitriding and aging process were optimized by modeling the phase transformations of the entire heat treatment procedure using DSC measurements. A comparison was made based on the in-depth hardness profile estimated by the so-called expanding cavity model (ECM), demonstrating that the hardness of the surface layer of the coated composite material systems is determined solely by the type of the coatings and does not influenced by the type of the applied substrate materials (bulk or 3D printed) or its heat treatment (whether it is a conventional, multi-step treatment or a simultaneous nitriding + aging process). Based on the research work, a proposal is suggested for modernizing and improving the cost-effectiveness of producing aged, duplex-treated, wear-resistant ceramic-coated maraging steel. Full article

Hydroxyapatite (HA) coatings improve implant bioactivity but suffer from brittleness and limited functionality. Here, we report a hybrid coating strategy combining flame-sprayed HA/TiO₂ with in situ hydrogel growth. TiO₂ incorporated into the HA matrix acted as a photocatalytic initiator for acrylamide polymerization under UV. Unlike conventional hydrogel coatings that require added photoinitiators or separate surface modification steps, TiO₂ incorporated into the HA layer serves as a built-in photocatalytic initiator, enabling direct polymerization of acrylamide monomers on the sprayed surface. The resulting HA/TiO₂–hydrogel coatings exhibited a continuous hydrogel layer with intimate contact to the ceramic surface, as evidenced by SEM cross-sections and elemental mapping. The HA/TiO₂ 1% coating produced a continuous coverage in close contact with the surface, while excessive TiO₂(5%) led to uncontrolled hydrogel growth and partial coating failure. SEM cross-sections revealed a dense, well-adhered coating with homogeneously distributed Ca, P, O, and finely dispersed Ti. Upon immersion in simulated body fluid (SBF), submicron globular deposits progressively developed on the coating surface. EDS showed an increase in Ca/P ratio from ~1.66 (as-sprayed) to ~1.92 (14 days). These findings highlight a straightforward approach for combining flame-sprayed ceramics with photocatalytic hydrogel growth, providing a practical route toward multifunctional implant surface modification. Full article

Rising incidents of critical lithium-ion battery (LIB) accidents highlight the pressing demand for safety enhancements that do not degrade the electrochemical performance parameters. This article provides a comprehensive overview of thermal failure mechanisms and thermal stability strategies, including their cathode, anode, separator, and electrolyte. The analysis covers the current thermal failure mechanisms of each component, including structural changes and boundary reactions, such as Mn dissolution in the cathode, solid–electrolyte interface decomposition in the anode, the melting–shrinkage–perforation of the separator, as well as decomposition–combustion–gas generation in the electrolyte. Furthermore, the article reviews thermal stability improvement methods for each component, including element doping and surface coating of the electrode, high-temperature resistance, flame retardancy, and porosity strategies of the separator, flame retardant, non-flammable solvent, and solid electrolyte strategies of the electrolyte. The findings highlight that incorporating diverse elements into the crystal lattice enhances the thermal stability and extends the service life of electrode materials, while applying surface coatings effectively suppresses the boundary reactions and structural degradation responsible for thermal failure. Furthermore, by using solid electrolytes such as polymer electrolytes, and combining innovative ceramic-polymer composite separators, it is possible to effectively reduce the flammability of these components and enhance their thermal stability. As a result, the overall thermal safety of LIBs is improved. These strategies collectively contribute to the overall thermal safety performance of LIBs. Full article

Bionic synthesis technology has made significant breakthroughs in porous functional materials by replicating and optimizing biological structures. For instance, biomimetic titanium dioxide-coated carbon multilayer materials, prepared via biological templating, exhibit a hierarchical structure, abundant nanopores, and synergistic effects. Bionic mineralization further enhances microcapsules by forming a secondary inorganic wall, granting them superior impermeability, high elastic modulus, and hardness. Through techniques like molecular self-assembly, electrospinning, and pressure-driven fusion, researchers have successfully fabricated centimeter-scale artificial lamellar bones without synthetic polymers. In environmental applications, electrospun membranes inspired by lotus leaves and bird bones achieve 99.94% separation efficiency for n-hexane–water mixtures, retaining nearly 99% efficiency after 20 cycles. For energy applications, an all-ceramic silica nanofiber aerogel with a bionic blind bristle structure demonstrates ultralow thermal conductivity (0.0232–0.0643 W·m⁻¹·K⁻¹) across a broad temperature range (−50 to 800 °C). This review highlights the preparation methods and recent advances in biomimetic porous materials for practical applications. Full article

The development of anode-free sodium metal batteries (AFSMBs) offers a promising pathway to achieve ultrahigh energy density and cost efficiency inherent to conventional sodium ion/metal batteries. However, irreversible Na plating/stripping and dendritic growth remain critical barriers. Herein, we demonstrate that separator engineering is a pivotal strategy for stabilizing AFSMBs. Through systematic evaluation of four separators—2500 separator (PP), 2325 separator (PP/PE/PP), glass fiber (GF), and an Al₂O₃-coated PE membrane, we reveal that the Al₂O₃-coated separator uniquely enables exceptional interfacial kinetics and morphological control. Na||Na symmetric cells with Al₂O₃ coated separator exhibit ultralow polarization (4.5 mV) and the highest exchange current density (1.77 × 10⁻² mA cm⁻²), while the anode-free AlC-NFPP full cells retain 91.6% capacity after 150 cycles at 2C. Specifically, the Al₂O₃ coating homogenizes Na⁺ flux, promotes dense and planar Na deposition, and facilitates near-complete stripping with minimal “dead Na”. This work establishes ceramic-functionalized separators as essential enablers of practical high-energy AFSMBs. Full article

High-entropy ceramics have gained wider attention due to their structural integrity and stability, which can be used in various functional applications. Especially, high-entropy oxides exhibit excellent thermal stability, particularly at high temperatures. Thermal barrier coating materials must demonstrate good thermal stability without any phase transformation or phase separation, which is critical in aerospace and energy conversion applications. To address this, we have prepared new high-entropy stannate pyrochlore oxide nanoparticles with the composition (Gd_0.2Nd_0.2La_0.2Pr_0.2Sm_0.2)₂Sn₂O₇ through a simple glycine-assisted sol–gel synthesis. The phase evolution was probed at different heat-treatment temperatures from 1000 °C to 1500 °C. Among the temperatures investigated, a single-phase pyrochlore oxide was formed from 1300 °C without any impurity or phase separation. The obtained nanoparticles were characterized using various techniques, including X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), nanoindentation, and dilatometry to investigate their physiochemical and mechanical properties. The Vickers hardness of high-entropy oxides is 4.2 ± 0.33 GPa, while a thermal expansion coefficient (TEC) of 8.7 × 10⁻⁶ K⁻¹ at 900 °C is calculated. The results show that the prepared high-entropy pyrochlore oxide can be a suitable candidate for thermal barrier coating. Full article

The wastewater from Chemical Mechanical Polishing (CMP) generated in the semiconductor industry contains a significant concentration of suspended particles and necessitates rigorous treatment to meet environmental standards. Ceramic ultrafiltration membranes offer significant advantages in treating such high-solid wastewater, including a high separation efficiency, environmental friendliness, and straightforward cleaning and maintenance. However, the preparation of high-precision ceramic ultrafiltration membranes with a smaller pore size (usually <20 nm) is very complicated, requiring the repeated construction of transition layers, which not only increases the time and economic costs of manufacturing but also leads to an elevated transport resistance. In this work, halloysite nanotubes (HNTs), characterized by their high aspect ratio and lumen structure, were utilized to create a high-porosity transition layer using a spray-coating technique, onto which a γ-Al₂O₃ ultrafiltration selective layer was subsequently coated. Compared to the conventional α-Al₂O₃ transition multilayers, the HNTs-derived transition layer not only had an improved porosity but also had a reduced pore size. As such, this strategy tended to simplify the preparation process for the ceramic membranes while reducing the transport resistance. The resulting high-flux γ-Al₂O₃ ultrafiltration membranes were used for the high-efficiency treatment of CMP wastewater, and the fouling behaviors were investigated. As expected, the HNTs-mediated γ-Al₂O₃ ultrafiltration membranes exhibited excellent water flux (126 LMH) and high rejection (99.4%) of inorganic particles in different solvent systems. In addition, such membranes demonstrated good operation stability and regeneration performance, showing promise for their application in the high-efficiency treatment of CMP wastewater in the semiconductor industry. Full article

The stability of thermal barrier coating (TBC) materials during service is a prerequisite for the normal operation of aircraft engines. The high-temperature corrosion of CaO–MgO–Al₂O₃–SiO₂ (CMAS) is an important factor that affects the stability of TBCs on turbine blades and causes premature engine failure. For traditional 6-8 YSZ, at temperatures of more than 1200 °C, the thermal insulation performance is significantly reduced, which makes it necessary to find new, alternative materials. La₂Zr₂O₇ has good thermal physical properties; the addition of Ce⁴⁺ improves its mechanical properties, while adding Gd₂O₃ affects its corrosion resistance. Herein, high-temperature corrosion studies of (La_1−xGd_x)₂(Zr_0.7Ce_0.3)₂O₇ (L-GZC) (x = 0, 0.3, 0.5, 0.7) ceramic TBC were conducted using CMAS glass at 1250 °C. The results indicate that CMAS rapidly dissolves L-GZC and separates the (La, Gd)₈Ca₂(SiO₄)₆O₂ apatite phase, ZrO₂, and other crystalline phases. These products form a crystalline layer at the contact boundary, which can inhibit further CMAS reactions. Among the coatings examined, the L-GZC ceramic (x = 0.7) exhibits better corrosion resistance, and the penetration depth is <200 μm after high-temperature corrosion at 1250 °C for 5, 10, and 20 h. The failure mechanism and potential risk of CMAS were also analyzed and discussed. The L-GZC ceramic material has good thermal corrosion resistance and is expected to replace the traditional YSZ to better meet the high-temperature working requirements of gas turbines and aircraft engines. Full article

The presence of pyrite in coal gangue significantly degrades the performance of its prepared kaolin in ceramic and coating applications. Implementing separation techniques to remove pyrite can markedly enhance the quality of kaolin products. However, there is no research on the effect of material particle size distribution on the separation effect in the current study on shaking table separation. For this reason, the coal gangue was crushed to different maximum particle sizes in this study, and its particle size distribution was fitted and analyzed. Based on the fitting results, the Rosin–Rammler–Sperling–Bennet (RRSB) distribution with a uniformity coefficient n of 0.74 was used to study the influence of the characteristic particle size d_e on the separation effect. Fuller distribution with distribution modulus q of 0.45 was also used to study the impact of maximum particle size d_max. The results showed that the Fuller distribution reduced the contents of SO₃ and Fe₂O₃ by 30.85% and 25.71%, respectively, compared with the raw materials. In comparison, the RRSB distribution reduced the contents of SO₃ and Fe₂O₃ by 41.01% and 30.85%, respectively, indicating that the separation effect of the RRSB distribution was better than that of the Fuller distribution. In addition, when the characteristic particle size d_e of the RRSB distribution was 37–42 μm, the content of SO₃ and Fe₂O₃ in the tailings varied very little, and the separation effect was stable. This study demonstrates that the particle size distribution significantly influences the separation efficiency of the shaking table, providing a novel idea for enhancing shaking table separation processes. Future studies may further explore the effect of another parameter or two-parameter coupling of RRSB distribution and Fuller distribution on the separation effect of the shaking table. Full article

Sodium–ion batteries are emerging as strong competition to lithium–ion batteries in certain market sections. While these cells do not use critical raw materials, they still feature a liquid electrolyte with all its inherent safety issues, like high flammability and toxicity. Alternative concepts like oxide-ceramic-based all-solid-state batteries feature the highest possible safety while still maintaining competitive electrochemical performance. However, production technologies are still in their infancy, especially for Na all-solid-state batteries, and need to be urgently developed to enable solid-state-battery technology using only abundant raw materials. In this study, the additive-free production of freestanding, undoped NaSICON separators via tape-casting is demonstrated, having an extremely high total Na-ion conductivity of up to 2.44 mS·cm⁻¹ at room temperature. Nevertheless, a strong influence of sample thickness on phase purity as well as electrochemical performance is uncovered. Additionally, the effect of self-coating of NaSICON during high-temperature treatment was evaluated as a function of thickness. While advantageous for increasing the stability against Na-metal anodes, detrimental consequences are identified when separator thickness is reduced to industrially relevant values and mitigation measures are postulated. Full article

Ceramic-coated polyolefin separator technology is considered a simple and effective method for the improvement of lithium-ion battery (LIB) safety. However, the characteristics of ceramic powder can adversely affect the surface structure and ion conductivity of the separators. Therefore, it is crucial to develop a ceramic powder that not only improves the thermal stability of the separators but also enhances ion conductivity. Herein, network spherical α-Al₂O₃ (N-Al₂O₃) with a multi-dimensional network pore structure was constructed. Furthermore, N-Al₂O₃ was applied as a coating to one side of polyethylene (PE) separators, resulting in N-Al₂O₃-PE separators that exhibit superior thermal stability and enhanced wettability with liquid electrolytes. Notably, the N-Al₂O₃-PE separators demonstrated exceptional ionic conductivity (0.632 mS cm⁻¹), attributed to the internal multi-dimensional network pore structures of N-Al₂O₃, which facilitated an interconnected and efficient “highway” for the transport of Li⁺ ions. As a consequence, LiCoO₂/Li half batteries equipped with these N-Al₂O₃-PE separators showcased remarkable rate and cycling performance. Particularly at high current densities, their discharge capacity and capacity retention rate significantly outperformed those of conventional PE separators. Full article

Lithium-ion batteries (LIBs) are well known for their energy efficiency and environmental benefits. However, increasing their energy density compromises their safety. This study introduces a novel ceramic-coated separator to enhance the performance and safety of LIBs. Electrospinning was used to apply a coating consisting of an alumina (Al₂O₃) ceramic and polyacrylic acid (PAA) binder to a polypropylene (PP) separator to significantly improve the mechanical properties of the PP separator and, ultimately, the electrochemical properties of the battery cell. Tests with 2032-coin cells showed that the efficiency of cells containing separators coated with 0.5 g PAA/Al₂O₃ was approximately 10.2% higher at high current rates (C-rates) compared to cells with the bare PP separator. Open circuit voltage (OCV) tests revealed superior thermal safety, with bare PP separators maintaining stability for 453 s, whereas the cells equipped with PP separators coated with 4 g PAA/Al₂O₃ remained stable for 937 s. The elongation increased from 88.3% (bare PP separator) to 129.1% (PP separator coated with 4 g PAA/Al₂O₃), and thermal shrinkage decreased from 58.2% to 34.9%. These findings suggest that ceramic/PAA-coated separators significantly contribute to enhancing the thermal safety and capacity retention of high-energy-density LIBs. Full article