Search Results (134)

Liquid electrolytes in conventional lithium-ion batteries pose safety risks associated with flammability, leakage, and explosion, whereas solid polymer electrolytes are generally limited by insufficient ionic conductivity at ambient temperature, restricting the development of high-energy lithium batteries. To address these issues, flexible poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)-based gel polymer electrolyte membranes (GPEs) were prepared via a slit-coating process combined with UV curing. NASICON-type lithium aluminum titanium phosphate (Li_1.3Al_0.3Ti_1.7P₃O₁₂, LATP) and garnet-type tantalum-doped lithium lanthanum zirconate (Li_6.4La₃Zr_1.4Ta_0.6O₁₂, LLZTO) were introduced as inorganic ceramic fillers to improve the ion-transport and interfacial properties of the GPE. Among the investigated samples, the PVDF-HFP-based GPE containing 10 wt% LLZTO exhibited the best overall performance, with an ionic conductivity of 3.40 × 10⁻⁴ S·cm⁻¹ at ambient temperature and a Li⁺ transference number of 0.77. Cyclic voltammetry results showed that the LLZTO-modified electrolyte membrane exhibited sharper and more symmetric redox peaks, higher peak current response, and better curve overlap during repeated cycles, indicating improved electrochemical reversibility and interfacial stability. In addition, LLZTO incorporation enhanced the mechanical strength, broadened the electrochemical stability window, and improved the flame-retardant behavior of the membrane. The LiFePO₄/GPE/Li cell assembled with the optimized membrane delivered an initial discharge capacity of 160 mAh·g⁻¹ at 0.1 C and maintained 80 mAh·g⁻¹ at 1 C, demonstrating good rate capability. Moreover, a capacity retention of 96% was maintained after 100 cycles at 0.1 C, confirming excellent cycling stability. Therefore, this work provides an effective strategy for the structural optimization and scalable preparation of high-performance gel polymer electrolyte membranes for lithium battery applications. Full article

The purpose of this study was to examine the utilization of 0–45 μm aluminum hydrate fraction (gibbsite) manufactured by Alum SA Tulcea, as a precursor in the hydrothermal synthesis process of nanosize boehmite from gibbsite suspensions. Furthermore, the use of the produced material as adsorbent of lanthanum (III) ions was investigated using aqueous solutions. Thermogravimetric analysis (TG), Fourier Transform InfraRed Spectroscopy (FT-IR), Wide-Angle X-Ray Scattering (WAXS), and atomic force microscopy (AFM) were used to demonstrate the preparation of the required material. Additionally, the material point of zero charge (pHpzc) and material specific surface (using BET approach) were evaluated. By conducting adsorption studies, the specific parameters for the lanthanum adsorption process were evaluated. The effects of pH, the ratio of adsorbent material to La(III) quantity from aqueous solution, contact time, and La(III) initial concentration were also assessed. Based on the obtained experimental data, it was proved that the maximum adsorption capacity of 97.7 mg/g was obtained for a solid:liquid ratio = 0.1 g:25 mL, pH between 3 and 6, temperature of 298 K, and contact time of 90 min. The studied adsorption process is most effectively described by the Sips model, suggesting an intricate interaction among the adsorbent material and La (III) ions. The prepared adsorbent exhibited a good desorption capacity (higher than 93%) when 20% HCl was used for desorption. Full article

Rare-earth elements including the fifteen lanthanides, from lanthanum (La) to lutetium (Lu), together with scandium (Sc) and yttrium (Y), can act either as matrix cations or as active luminescent centers when incorporated into host lattices. Owing to their relatively large ionic radii, high coordination numbers, and structural stability, ions such as La, Lu, Sc, Y, and gadolinium (Gd) typically serve as matrix cations in rare-earth vanadate (REVO₄)-based phosphors, while other trivalent lanthanide (Ln³⁺) ions act as active luminescent centers. These REVO₄ phosphors have proved to be good host lattices for optically active Ln³⁺ ions giving strong luminescence assigned to absorption of the vanadate (VO₄³⁻) groups, and the efficient energy transfer between host lattice and Ln³⁺ ions. The unique electronic configuration of Ln³⁺ ions, particularly their unpaired 4f electrons, makes them ideal for applications in luminescence, magnetism, electronic and magnetic relaxation, and catalysis. Due to their complementary luminescent characteristics, Ln³⁺-doped REVO₄ phosphors have attracted significant attention in recent years. Their unique optical properties make them highly valuable across a broad spectrum of applications. This paper provides a comprehensive review of the state of the art in Ln³⁺ (Eu³⁺, Sm³⁺, Tm³⁺, Er³⁺, Ho³⁺, Tb³⁺, Nd³⁺, and Yb³⁺)-doped REVO₄ (RE = Y, Gd, Lu, La) phosphors. It examines current synthesis approaches, alongside the development of advanced strategies, and explores structural characteristics, innovative designs, and luminescent behavior, including both downconversion and upconversion processes and sensing applications, of the Ln³⁺-doped REVO₄ phosphors. Full article

Lanthanum silicate oxyapatite (LSO) is a promising oxide ion conductor for low-temperature-operating electrochemical devices owing to its high ionic conductivity along the c-axis. However, the fabrication of thin films with controlled crystallographic orientation remains challenging. In this study, polymer-assisted deposition (PAD), a solution-based technique offering precise microstructural and compositional control, was employed to fabricate c-axis-oriented LSO thin films. The fabrication of undoped LSO and the effects of Al and Mg incorporation on its microstructure, orientation, and ionic conductivity were systematically investigated. Undoped LSO thin films crystallised with a preferential c-axis orientation in the annealing temperature range of 800 and 1100 °C, and scanning transmission electron microscopy observations revealed a highly crystalline, void-free microstructure. Upon annealing at 1200 °C, the undoped LSO exhibited columnar grains with anisotropic in-plane grain growth, whereas Al- or Mg-doped LSO suppressed anisotropic in-plane grain growth and retained an out-of-plane c-axis orientation. The undoped LSO showed higher in-plane ionic conductivity than the doped thin films, consistent with their distinct crystallographic orientations. These results demonstrate that PAD provides a viable pathway for tailoring the microstructure and the composition of LSO thin films, thereby facilitating their applications in solid oxide electrochemical devices. Full article

Water with a high fluoride content poses a serious threat to both public health and the natural environment. To enhance fluoride ion removal efficiency, a modified activated carbon adsorbent (HPAC-La) was synthesized by impregnating soybean protein in a lanthanum nitrate solution, followed by freezing–drying and carbonization. The results confirmed that lanthanum nitrate modification significantly improved the adsorption performance. Under optimised experimental conditions (pH = 2.0, [F⁻] = 300 mg·L⁻¹, 12 h, 298 K), HPAC-La exhibited a maximum adsorption capacity for fluoride ions of 126.7 mg·L⁻¹, significantly higher than that of unmodified HPAC (86.1 mg·L⁻¹). The adsorption process followed the pseudo-second-order kinetic model and the Langmuir isotherm model, indicating monolayer chemisorption. The mechanism involves ion exchange via surface hydroxyl groups and fluoride coordination with La sites. This study proposes a method for developing highly efficient adsorbents for the treatment of fluoride-contaminated wastewater. Full article

The efficient recovery of rare earth elements (REEs) from low-concentration mine tailwater is crucial for resource sustainability. In this study, a novel composite adsorbent, sesame stalk biochar-supported zirconium phosphate (sBC/ZrP), was synthesized for the selective adsorption and recovery of La³⁺ as a representative REE. The material was characterized using SEM-EDS, BET, XRD, FTIR, and XPS. Batch adsorption experiments were conducted to evaluate the effects of pH, coexisting ions, and the adsorption kinetics and thermodynamics. The results showed that sBC/ZrP exhibited a high adsorption capacity (up to 185.83 mg/g at 35 °C for 4 h) and strong selectivity for La³⁺, particularly in the presence of common competing cations, although Al³⁺ demonstrated significant interference. The adsorption process followed pseudo-second-order kinetics and the Langmuir isotherm model, indicating monolayer chemisorption, and was determined to be spontaneous and endothermic. The material maintained over 90% adsorption efficiency after five consecutive adsorption–desorption cycles. The mechanism primarily involved complexation of La³⁺ with the P-OH and Zr-O groups on the composite. This work demonstrates that sBC/ZrP is a highly efficient, stable, and reusable adsorbent with significant potential for the recovery of REEs from mining tailwater. Full article

Light-controlled ion drag pumps have attracted considerable interest in soft robotics, biomedical engineering, and microelectromechanical systems (MEMS) due to their non-contact energy supply and high spatiotemporal controllability of light. However, experimental studies on their pumping performance and influencing factors remain limited. This study integrates the photoelectric effect with field emission phenomena to design and fabricate a light-controlled ion drag pump using lanthanum-modified lead zirconate titanate (PLZT) ceramic. The light-controlled pump enables non-contact energy transfer and fluid transport via high-energy laser irradiation. A series of experiments systematically investigate its pumping performance and key influencing factors. Results indicate that optimizing electrode structure and fluid channel design, along with increased light intensity, significantly enhances pumping performance. This work provides fundamental design guidelines for the application of light-controlled ion drag pumps in microfluidics, flexible robotics, and microdevice thermal management. Full article

Hydrometallurgy is currently the mainstream industrial process for recovering valuable components (nickel, cobalt, manganese, lithium, etc.) from spent ternary lithium-ion battery cathode materials. During the crushing of lithium batteries, cathode materials, anode materials (graphite), and electrolytes become mixed. Consequently, fluoride ions inevitably enter the leaching solution during the hydrometallurgical recycling process, with concentrations as high as 100–300 mg/L. These fluoride ions not only adversely affect the quality of the recovered precursor products but also pose environmental risks. To address this issue, this study employs a synthesized lanthanum–zirconium (La@Zr) composite material, with a specific surface area of 67.41 m²/g and a pore size of 2–50 nm, which can reduce the fluoride ion concentration in the leaching solution to below 5 mg/L, significantly lower than the 20 mg/L or higher that is typically achieved with traditional calcium salt defluorination processes, without introducing new impurities. Under optimal adsorption conditions, the lanthanum–zirconium adsorbent exhibits a fluoride ion adsorption capacity of 193.4 mg/g in the leaching solution, surpassing that of many existing metal-based adsorbents. At the same time as the valuable metals, Li, Ni, and Co, are basically not adsorbed, the selective adsorption of fluoride ions can be achieved. Adsorption isotherm studies indicate that the adsorption process follows the Langmuir model, suggesting monolayer adsorption. The secondary adsorption process is primarily governed by chemical adsorption, and elevated temperatures facilitate the removal of fluoride ions. Kinetic studies demonstrate that the adsorption process is well described by the pseudo-second-order model. After desorption and regeneration with NaOH solution, the adsorbent still has a favorable fluoride removal performance, and the adsorption rate of fluoride ions can still reach 95% after four cycles of use. With its high capacity, rapid kinetics, and excellent selectivity, the adsorbent is highly promising for large-scale implementation. Full article

Calcium is an essential macronutrient for plant growth and development, and there is an optimal calcium concentration for plant growth. Calcium ion concentration changes create “calcium signals” that regulate plant growth through perception, decoding, transduction, and response processes. However, the mechanisms by which calcium signaling regulates photosynthesis are still not fully understood. In this study, Quercus acutissima seedlings were used to investigate the inhibitory effects of different concentrations of the calcium channel blocker lanthanum chloride (LaCl₃) on photosynthesis and the underlying mechanisms. The results show that increasing LaCl₃ concentration significantly decreased photosynthetic parameters, photosynthetic pigment contents, and photosynthetic product accumulation. Long-term water use efficiency decreased with increasing LaCl₃ concentration, while instantaneous water use efficiency initially increased and then decreased. Structural equation modeling analysis indicated that LaCl₃ concentration was significantly positively correlated with leaf calcium concentration in Quercus acutissima seedlings, while it was significantly negatively correlated with stomatal conductance, carotenoids, and soluble sugar content. The study concludes that LaCl₃ directly inhibits the photosynthetic physiological processes of Quercus acutissima seedlings by blocking calcium signaling, providing insights into the regulatory mechanisms of calcium signaling in plant photosynthesis and a theoretical basis for the cultivation and application of Quercus acutissima under varying environmental conditions. Full article

Lanthanum-cerium rare earth (RE) elements play a vital role in metallurgy as essential microalloying elements. Their addition significantly modifies inclusion characteristics, enhances mechanical properties, and improves corrosion resistance. This review emphasizes the distinct and synergistic roles of lanthanum (La) and cerium (Ce) in steel at the atomic scale, elucidated through first-principles calculations based on density-functional theory (DFT). The primary focus includes the nucleation mechanisms and characteristics of rare earth inclusions, the solid solution and segregation behavior of rare earth atoms, and their microalloying effects on electronic structure and interfacial bonding. Although both elements form stable inclusions Re₂O₃ and ReAlO₃ and exhibit grain refinement effects, Ce exhibits a unique dual valence state (Ce³⁺/Ce⁴⁺). This results in nucleation behavior and oxide stability for Ce ions that differ slightly from those of La. Both elements alter the electronic structure of the Fe matrix through hybridization with d-orbitals, reducing magnetic moment and enhancing toughness. Compared to other alloying elements, La and Ce exhibit unique behaviors due to their large atomic radii and high chemical reactivity, which influence their solid solubility, segregation tendencies, and interactions with other atoms such as Cr, C, and N. Finally, this paper discusses the challenges that exist when first-principles computational methods are used to study the mechanism of action of RE elements in steel, and proposes measures and methods to address these challenges, aiming to provide an in-depth understanding of the mechanism of action of REs in steel at the microscopic level and to promote the application of computational chemistry in the field of metallurgy. Full article

This work develops a novel phosphate-functionalized extraction resin (HEHEHP + Cyanex272)/SiO₂-P via the vacuum impregnation method for efficient separation of light rare earth element impurities from lanthanum (La³⁺) in nitric medium through synergistic extraction. Batch experiments have demonstrated superior adsorption selectivity toward impurity ions over La³⁺ in a pH 4 nitric acid solution. Column studies confirmed exceptional performance under ambient conditions, achieving a lanthanum treatment capacity of 120.6 mg/g and over 98% impurity removal, which surpasses most reported values. Notably, this purification process enables direct production of purified La³⁺ solutions through a single-column system without desorption, significantly enhancing efficiency and reducing costs. Mechanistic insights revealed combined ion exchange and coordination interactions between metal ions and P-OH/P=O groups, corroborated by advanced characterization and density functional theory calculations. These findings indicate a higher binding affinity of light rare earth compared with La³⁺. This strategy provides a scalable approach for ultra-high-purity lanthanum compound production in advanced optical and electronic applications. Full article

The experimental IR and Raman vibrational spectra of a hydrated La(III) complex with a 1,2,3-triazole ligand were characterized by using four different Density Functional Theory (DFT) levels and two accurate scaling procedures. In the theoretical calculations, the hydration water in the experimental sample was considered under the Discrete Model (DM) with different numbers of explicit water molecules and different positions around the La(III) ion and the carboxylate groups. The predicted IR spectra at the M06-2X/Lanl2dz level appear to be the closest to the experimental ones. Based on the optimized structures, molecular properties and global chemical descriptors were also calculated, and the findings obtained are discussed in detail herein. Additionally, several photophysical properties were determined in both the free ligand and in several lanthanide complexes, and with the sample in the solid state and in DMSO solution. A blue shift in the fluorescence of the complexes was observed compared to the free ligand, as well as in the solid-state sample compared to the solution. Full article

The development of high-performance solid electrolytes is critical to advancing solid-state lithium-ion batteries (SSBs), with lithium lanthanum zirconium oxide (LLZO) emerging as a leading candidate due to its chemical stability and wide electrochemical window. In this study, we systematically investigated the effects of cation dopants, including aluminum (Al³⁺), tantalum (Ta⁵⁺), gallium (Ga³⁺), and rubidium (Rb⁺), on the structural, electronic, and ionic transport properties of LLZO using density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations. It appeared that, among all simulated results, Al-LLZO exhibits the highest ionic conductivity of 1.439 × 10⁻² S/cm with reduced activation energy of 0.138 eV, driven by enhanced lithium vacancy concentrations and preserved cubic-phase stability. Ta-LLZO follows, with a conductivity of 7.12 × 10⁻³ S/cm, while Ga-LLZO and Rb-LLZO provide moderate conductivity of 3.73 × 10⁻³ S/cm and 3.32 × 10⁻³ S/cm, respectively. Charge density analysis reveals that Al and Ta dopants facilitate smoother lithium-ion migration by minimizing electrostatic barriers. Furthermore, Al-LLZO demonstrates low electronic conductivity (1.72 × 10⁻⁸ S/cm) and favorable binding energy, mitigating dendrite formation risks. Comparative evaluations of radial distribution functions (RDFs) and XRD patterns confirm the structural integrity of doped systems. Overall, Al emerges as the most effective and economically viable dopant, optimizing LLZO for scalable, durable, and high-conductivity solid-state batteries. Full article

Lithium lanthanum titanate (LLTO) is a promising solid electrolyte for all-solid-state lithium-ion batteries (ASSLIBs), and its total conductivity is dramatically influenced by the ceramic microstructure. Here we report a novel aerodynamic levitation rapid solidification method to prepare dense LLTO ceramics with a dendrite-like microstructure, which can be hardly obtained by conventional sintering. At optimal nominal lithium content and cooling rate, the solidified LLTO ceramic achieved a high total conductivity of 2.5 × 10⁻⁴ S·cm⁻¹ at room temperature, along with excellent mechanical properties such as a high Young’s modulus of 240 GPa and a high hardness of 16.7 GPa. Results from this work suggest that aerodynamic levitation rapid solidification is an effective processing method to manipulate the microstructure of LLTO ceramics to minimize the GBs’ contribution to the total conductivity, which may be expanded to prepare other oxide-type lithium electrolytes. Full article

In this study, lanthanum–nitrogen co-doped titanium dioxide (La-N-TiO₂) thin films were fabricated using Ion Beam Assisted Deposition (IBAD) and subjected to accelerated ultraviolet (UV) aging experiments to systematically investigate the impact of co-doping on the films’ resistance to UV aging. X-ray diffraction (XRD) analysis revealed that La-N co-doping inhibits the phase transition from anatase to rutile, significantly enhancing the phase stability of the films. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) characterizations indicated that co-doping increased the density and surface uniformity of the films, thereby delaying the expansion of cracks and increase in roughness induced by UV exposure. Energy-dispersive X-ray spectroscopy (EDS) results confirmed the successful incorporation of La and N into the TiO₂ lattice, enhancing the chemical stability of the films. Contact angle tests demonstrated that La-N co-doping markedly improved the hydrophobicity of the films, inhibiting the rapid decay of hydrophilicity during UV aging. After three years of UV aging, the co-doped films maintained high structural integrity and photocatalytic performance, exhibiting excellent resistance to UV aging. These findings offer new insights into the long-term stability of photovoltaic self-cleaning materials. Full article