Search Results (603)

Although garnet-type Li₇La₃Zr₂O₁₂ (LLZO) solid electrolytes are promising candidates for high-energy-density all-solid-state batteries, their practical applications are limited by high-voltage oxidation instability and interfacial degradation. To address these limitations, Al-doped LLZO (Al-LLZO) solid electrolytes were synthesized via a conventional solid-state reaction method, and the effects of PE-ALD-derived Al₂O₃ nanocoatings on electrochemical properties and interfacial stability were investigated. Al₂O₃ nanocoatings with different structures (5 and 10 nm single-side, and 5 nm double-side) were deposited on Al-LLZO pellets using plasma-enhanced atomic layer deposition. The Al₂O₃ coating reduced electronic conductivity by approximately one order of magnitude while maintaining similar ionic conductivity. Linear sweep voltammetry revealed that initial oxidation onset voltage increased from ~4.2 V (bare Al-LLZO) to ~5.0 V (5 nm-coated samples), while the 10 nm-coated sample exhibited the most delayed anodic current response (~5.2 V). The 5 nm double-side coated sample showed the best Li plating/stripping stability with a critical current density of 1.10 mA/cm² and stable long-term galvanostatic cycling behavior over 200 h at 0.05 mA/cm². Thus, ALD-based Al₂O₃ interfacial engineering can simultaneously improve the high-voltage oxidation and Li metal interfacial stabilities of garnet-type Al-LLZO solid electrolytes for practical all-solid-state batteries. Full article

Lead-free [(Ba_0.85Ca_0.15)_1−1.5xNd_x][(Zr_0.1Ti_0.9)_0.995Mn_0.005]O₃ (x mol% Nd/Mn BCZT, x = 0.05, 0.1, 0.5, 1 mol%) ceramics were prepared by the traditional solid-state reaction method, in which the synergistic effects of sintering temperature and Nd/Mn co-doping on the phase structure, microstructural evolution, and electrical properties were systematically investigated. All ceramics exhibit a pure perovskite structure, with the tetragonal (P4mm) phase dominating at room temperature as confirmed by the X-ray diffraction Rietveld refinement. The sintering temperature (1475–1520 °C) is found to be the primary factor governing densification and grain growth, with the relative density peaking at 91.7% for the x = 0.5 mol% sample sintered at 1505 °C. Within this optimized processing window, increasing the Nd content induces a gradual migration of the Curie temperature (T_C) toward lower temperatures, accompanied by enhanced relaxor behavior. A highlight of this work is the strategic balance between piezoelectric activity and mechanical quality factor through a “donor–acceptor” co-doping mechanism. Specifically, for the x = 0.5 mol% ceramics, an exceptionally high mechanical quality factor (Q_m = 424.5) is achieved for samples sintered at 1490 °C, which is proposed to be associated with the temperature-modulated formation of ${Mn}_{Ti}^{″}-V_O^{••}$ defect dipoles, while a peak inverse piezoelectric coefficient $d_{33}^{*}$ of 685.1 pm/V is maintained at a sintering temperature of 1520 °C. Full article

High-entropy alloy (HEA) coatings exhibit enhanced chemical stability when doped with carbon, primarily due to the strong bonding between carbon and transition metals. Typical transition metals used in these coatings include Cr, Fe, Co, Ni, Cu, Ti, V, W, Nb, Ta, and Zr. Owing to their excellent chemical stability, HEA coatings are widely employed to protect component surfaces operating in highly corrosive environments. Against this backdrop, the present study investigates the effect of carbon doping introduced via methane gas flow during the physical vapor deposition of TiAlTaZrNb HEA coatings on corrosion resistance. The morphology and structure of the coatings were analyzed by field emission scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. Corrosion protection and coating resistance were assessed through potentiodynamic polarization and electrochemical impedance spectroscopy. While increasing the methane flow resulted in an approximately 34% reduction in coating thickness, the overall coating resistance increased by one order of magnitude, reaching a maximum at a methane flow rate of 9 sccm, corresponding to the carbon solubility limit. This improvement was evidenced by a decrease in the corrosion rate from 8.02 × 10⁻² mm y⁻¹ for the uncoated H13 steel to 8.00 × 10⁻⁴ mm y⁻¹ for the HEA-coated samples. However, at higher methane flow rates, carbon precipitation and the formation of parallel microcracks contributed to an increase in corrosion rate. Full article

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

Flexible oxide electronics require dielectric layers that combine low-temperature processability, low leakage current, high capacitance density, and mechanical reliability. In this work, we prepared ZrAlO_x-PVP hybrid dielectric films through a low-temperature self-combustion solution process at 180 °C and systematically investigated the effect of PVP doping (0–2 wt%). The results show that PVP promotes the formation of M-O-C related bonding environments, suggesting the construction of an organic–inorganic crosslinked structure. Moderate PVP incorporation effectively suppresses leakage pathways, whereas excessive PVP induces polymer aggregation and trap-assisted conduction. Among all samples, the film on flexible PI (polyimide) with a PVP doping concentration of 0.5 wt% exhibits the best overall performance, with a leakage current as low as 1.89 × 10⁻⁸ A/cm² at 1 MV/cm, a dielectric constant of 8.88. After static bending at a radius of 20 mm, the film maintains stable dielectric behavior, indicating improved stress tolerance. Flexible IGZO TFT fabricated with the optimized dielectric shows a mobility of 11.84 cm² V⁻¹ s⁻¹, a threshold voltage of 0.48 V, and a subthreshold swing of 0.24 V dec⁻¹ before bending. This work demonstrates that moderate PVP crosslinking provides an effective balance between defect suppression and stress relaxation, offering a practical interface-engineering strategy for low-temperature flexible high-k dielectrics. Full article

N-doped Li₂ZrCl_6−3xN_x chloride solid electrolytes were synthesized via a mechanochemical method, and the effects of N incorporation on crystal structure, Li local environment, and Li⁺ transport were systematically investigated. X-ray diffraction suggested that the main Li₂ZrCl₆-related diffraction features were largely retained, while N introduction induced partial structural evolution toward C2/m-related features. 7Li MAS NMR revealed that N incorporation sharpened Li resonance peaks. Among the series, Li₂ZrCl_5.7N_0.1 exhibited the highest room-temperature ionic conductivity of 1.15 mS cm⁻¹, with the lowest activation energy of 0.237 eV, demonstrating a reduced Li⁺ migration barrier. All-solid-state batteries incorporating Li₂ZrCl_5.7N_0.1 showed stable rate capability and long-term cycling, retaining 85.9% capacity after 500 cycles at 1C and 77.4% after 3000 cycles at 3C. These results suggest that appropriate N modification can tune the Li₂ZrCl₆-based structure and Li local environment, thereby improving Li⁺ transport in all-solid-state lithium batteries. This work provides a feasible strategy for improving chloride-based solid electrolytes for next-generation energy storage. Full article

Background/Objectives: Titanium alloy Ti₆Al₄V remains the gold standard in dental implantology due to its excellent mechanical properties, corrosion resistance, and biocompatibility. However, implant-associated infections and insufficient osseointegration continue to represent major clinical challenges, mainly related to bacterial biofilm formation and suboptimal surface–tissue interactions. Biofilm formation refers to the adhesion, accumulation, and growth of microbial communities embedded within a self-produced extracellular polymeric matrix on implant surfaces, which contributes to bacterial persistence and resistance to host defense mechanisms. This review aims to critically evaluate recent advances in multifunctional bioceramic coatings for dental implants, with a particular focus on zirconia (ZrO₂)-based systems and their antibacterial mechanisms. Methods: A structured literature analysis was conducted using major scientific databases including PubMed, Scopus, and Web of Science, focusing mainly on studies published between 2015 and 2025 related to CaP, Ag, and ZrO₂-based coatings for dental implants. The review examines their physicochemical properties, antibacterial strategies, ion release behavior, and biological responses, including osteogenic activity and biofilm inhibition. Particular attention is given to hybrid systems integrating multiple functional phases. Results: CaP coatings exhibit excellent osteoconductivity and promote early osseointegration but show limited intrinsic antibacterial activity. Ag-based coatings provide strong broad-spectrum antimicrobial effects through controlled Ag⁺ ion release, although concerns regarding cytotoxicity and dose-dependent responses remain. ZrO₂ coatings significantly enhance corrosion resistance and surface stability, while their antibacterial performance can be improved through nanostructuring, laser surface modification, and ionic doping. Hybrid Ag–CaP–ZrO₂ coatings demonstrate improved antibacterial activity, enhanced corrosion resistance, and better regulation of ion release kinetics and osteogenic response compared with single-component coating systems. Conclusions: Multifunctional bioceramic coatings represent a promising strategy for improving the performance of dental implants and addressing the dual challenge of infection control and tissue integration. However, challenges remain regarding long-term stability, controlled ion release, and limited clinical validation. Future research should focus on the development of smart, stimuli-responsive coatings and standardized evaluation protocols to facilitate clinical translation. Full article

Understanding lithium distribution and transport within Li-ion battery components is critical in improving battery longevity, safety and performance. This study investigates lithium concentration profiles across the interface of an aluminum-doped Li₇La₃Zr₂O₁₂ (Al-LLZO) solid electrolyte and a lithium metal anode using Nuclear Reaction Analysis (NRA), a non-destructive depth-profiling technique. The Al-LLZO electrolyte was synthesized via electrospinning, producing nanofibers, which were subsequently sintered into pellets of average thickness 380 µm. These pellets were integrated into a Li|Al-LLZO|NMC-111 half-cell and cycled at 0.1 C for 1, 3, and 10 cycles, indicating pronounced lithium accumulation at the electrolyte–anode interface. Using NRA, this study provided a clear pathway for better understanding lithium transport and interfacial behavior, by quantitatively measuring the lithium distribution at the Al-LLZO electrolyte–electrode interface, and to look at the changes at this interface over the battery cycles. Full article

This study explored the influence of high silver (Ag) loading (5–10 mol%) on the photocatalytic performance of zirconium (Zr) co-doped TiO₂ (AZT) with a low Zr content. Although various Ag/Zr ratios have been reported, the effect of high Ag loading combined with low Zr content remains largely unrevealed, particularly in low-temperature synthesis where the role of Zr as a phase inhibitor is less critical. To address this gap, the AZT photocatalyst was fabricated via a solvothermal method combined with organic-free peroxy route. Characterization indicated Zr⁴⁺ incorporated into the TiO₂ lattice, inducing structural distortions and promoting Ti³⁺ defect states. Simultaneously, silver existed as ternary Ag species, which functioned as visible light responsive co-catalysts that enhanced light absorption via Surface Plasmon Resonance (SPR) and facilitated efficient charge separation. Photocatalytic performance was evaluated through Methylene Blue (MB) decolorization under household LED lamp. The optimized 7% Ag loaded catalyst achieved 99.4% removal efficiency within 6 h, with a reaction rate ten times higher than the Zr-doped sample. This superior activity was attributed to a p-n heterojunction and the SPR effect, narrowing the optical band gap to 2.60 eV. Radical scavenger experiments confirmed that the process was primarily driven by photogenerated holes. Full article

Pr³⁺-activated phosphors are promising for non-contact optical thermometry under blue-light excitation. In tantalate hosts, Pr³⁺-Ta⁵⁺ intervalence charge transfer (IVCT) states may introduce thermally activated nonradiative pathways involving the ³P₀ and ¹D₂ levels, thus affecting their thermal quenching behavior and thermometric performance. However, the concentration- and temperature-dependent luminescence of CaTa₂O₆:Pr³⁺ remains unexplored. In this study, CaTa₂O₆:Pr³⁺ phosphors were synthesized via the solid-state reaction method, and a phosphor-in-glass (PiG) composite was fabricated by co-sintering the mixture of the phosphor and the precursor glass (PG) powder. The structural characteristics and the luminescence properties of CaTa₂O₆:Pr³⁺ phosphors under 450 nm excitation were investigated. The IVCT band was confirmed in the excitation spectrum. Optimal Pr³⁺ concentrations were 2 mol% for ³P_J and 0.7 mol% for ¹D₂ emissions. With Pr³⁺/Zr⁴⁺ or Pr³⁺/Sn⁴⁺ co-doping, the emission intensity was enhanced by 1.34 and 1.31 times, respectively. The PiG exhibited similar spectral profiles. An FIR mode based on ³P₁→³H₅/³P₀→³F₂ transitions achieved maximum relative sensitivities of 1.09% K⁻¹ for the phosphor and 1.18% K⁻¹ for the PiG at 298 K. These findings suggest that CaTa₂O₆:Pr³⁺-based materials are potential candidates for luminescence thermometry. Full article

Lead-free piezoelectric ceramics have attracted substantial attention in environmental protection and energy storage applications due to their excellent performance. In this study, the Ba_1−xCa_xZr_0.1Ti_0.9−ySn_yO₃(BCZTS) lead-free piezoelectric ceramic system was synthesized. The effects of doping ratios of Ca and Sn, as well as sintering temperature, were systematically investigated on the phase structure, microstructure, and piezoelectric properties of BCZTS ceramics. The results showed that the Ba_0.88Ca_0.12Zr_0.1Ti_0.81Sn_0.09 ceramics synthesized with a Ca doping content of x = 12 mol% and a Sn doping content of y = 9 mol % had a homogeneous phase structure with an Orthorhombic–Tetragonal (O-T) morphotropic phase boundary (MPB) and uniform grain size. At a sintering temperature of 1300 °C, the ceramics achieved optimal piezoelectric performance, with a piezoelectric coefficient d₃₃ = 319 pC/N. These lead-free piezoelectric ceramics have superior properties compared to conventional lead-based piezoelectric ceramics in the local market, providing a novel and feasible way to replace lead-based ones in civilian applications. Full article

The article presents the synthesis and characterization of double halide perovskites (DHPs) with the nominal composition Cs₂Ag_0.2Na_0.4In_0.6M_0.4Cl₆ (M = Si, Ti, Zr), including photoluminescence (PL), photoluminescence excitation (PLE) spectra measured over a range of temperatures and kinetics of luminescence. The materials were synthesized via a hydrothermal method. The phase purity and elemental composition of the synthesized perovskites were confirmed by X-ray diffraction (XRD), Rietveld refinement, scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS) and elemental analysis, which demonstrated that the samples showed a close match to the target stoichiometry. The PL spectra exhibit a systematic shift toward the lower-energy region with substitution from Si to Zr, correlating with the progressive increase in the ionic radii of the substituting cations. All samples display broad, asymmetric emission bands, characteristic of self-trapped excitonic (STE) states. Temperature-dependent PL measurements reveal a gradual decrease in emission intensity with increasing temperature for all samples. The maximum emission intensity is observed in the range of ~160–200 K, corresponding to optimal conditions for radiative recombination, whereas the lowest intensity is recorded at ~80–100 K, where thermal activation of radiative centers is minimal. An increase in temperature is accompanied by a red shift in the PL bands across all compositions. In the Ti-doped DHP, a pronounced blue shift at low temperatures is observed, which can be attributed to the involvement of Ti³⁺-related electronic states. An analysis of the activation energy of thermal luminescence quenching and the results of time-resolved spectroscopy revealed the activation of thermal processes in the titanium-containing sample and their rapid decay, whereas replacing titanium with silicon leads to more stable luminescence in the crystal under study. Thus, the enhanced luminescence characteristics of double halide perovskites doped with Ti, Si, and Zr highlight their potential for advanced photonic and optoelectronic applications. Full article

The safe immobilization of high-level waste (as actinide) remains a critical bottleneck in the disposal of high-level radioactive waste worldwide. Moreover, the higher specific surface area and surface energy of nano-scale powders enable the production of ceramic materials featuring denser crystal structures and superior strength, hardness, and toughness. Therefore, in this study, Gd³⁺ was used as a surrogate for actinides, and Nb⁵⁺ was introduced as a high-valence charge-compensating cation. Nano-scale powders of CaCO₃, ZrO₂, Gd₂O₃, TiO₂, and Nb₂O₅ were employed to prepare a series of defect-fluorite-derived ceramics, CaZr_1-xGd_xTi_2-xNb_xO₇ (x = 0.1–1.0), via a high-temperature solid-state reaction method, aiming to investigate the atomic substitution mechanisms, phase evolution, and chemical stability under high-valence charge compensation. Laboratory X-ray diffraction (XRD), synchrotron X-ray diffraction (SXRD), and backscattered scanning electron microscopy with energy-dispersive X-ray spectroscopy (BSEM-EDX) confirmed a phase evolution sequence from zirconolite-2M to zirconolite-4M and finally to pyrochlore. This behavior is consistent with that reported for other Ln³⁺-Nb⁵⁺ co-doped zirconolite systems. Rietveld refinement of the SXRD data further revealed, for the first time, the site-occupancy mechanism of Gd and Nb in zirconolite-4M. In both zirconolite-2M and zirconolite-4M, Gd preferentially occupies the Ca sites, whereas Nb substitutes at the Ti sites. In the pyrochlore structure, Ca, Zr, and Gd occupy the 16d sites, while Ti and Nb occupy the 16c sites. Static leaching tests following the MCC-1 protocol showed that pyrochlore exhibits the highest leaching resistance, whereas zirconolite-2M shows the lowest. After 28 days, the highest Gd leaching rate was 1.92(1) × 10⁻⁵ g m⁻² d⁻¹. These results provide new insights into actinide immobilization behavior and compositional design in zirconolite-based waste forms. Full article

Yttrium doping has been reported to be an effective approach to enhance the mechanical and protective properties of ZrN coatings by magnetron sputtering. Nitrogen (N₂) flow ratio during reactive magnetron sputtering is known to critically influence the stoichiometry, defect structure, and microstructure of nitride coatings. However, its systematic effect on Y-doped ZrN (ZrYN) coatings has remained unexplored. In this work, ZrYN coatings with a fixed Y content were deposited by reactive magnetron sputtering under varying N₂ flow ratios (0–10%). Their microstructure, mechanical properties, corrosion resistance in 3.5 wt% NaCl solution, and oxidation behavior at 650 °C were systematically investigated. Below 5% N₂ flow ratio, the coatings are metallic ZrY, showing very low hardness, poor corrosion resistance, and catastrophic oxidation failure. At N₂ flow ratio ≥ 5%, cubic ZrYN forms, with stoichiometry varying from sub-stoichiometric (5%) to near-stoichiometric (7.5%) to over-stoichiometric (10%). The near-stoichiometric coating at 7.5% exhibits the finest columnar grains and densest microstructure, leading to the highest hardness (32.2 ± 1.4 GPa) and an elastic modulus of (469.6 ± 24.5 GPa), as well as the best corrosion resistance (two orders of magnitude lower than bare 316 stainless steel). Upon oxidation, it forms a thin and dense epitaxial t-ZrO₂ scale stabilized by Y₂O₃, suppressing the destructive tetragonal to monoclinic transformation. Off-stoichiometric coatings at 5% and 10% develop thicker, cracked oxide scales and show inferior properties. Precise control of N₂ flow ratio is therefore essential to achieve a near-stoichiometric ZrYN coating with superior mechanical, anti-corrosion, and anti-oxidation performance. Full article

This study investigates the formation mechanism of non-doped cubic lithium lanthanum zirconium oxide (c-LLZO) nanofibers using in situ synchrotron X-ray scattering techniques. Electrospun polymer precursor nanofibers were annealed at temperatures up to 800 °C, enabling real-time tracking of phase transitions via simultaneous small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS), and evolved CO₂ gas analysis. The results reveal a three-step transformation pathway: polymer decomposition, formation of La₂Zr₂O₇ (LZO), and direct conversion of LZO to c-LLZO without intermediate tetragonal phases detected within the sensitivity of our in situ WAXS measurement. Cryo-electron energy loss spectroscopy (EELS) further elucidates the role of lithium diffusion, showing Li enrichment at fiber surfaces and Li deficiency in the interior, which stabilizes the cubic phase. This Li segregation effect in nanostructured LLZO materials extends beyond the previously reported size effect. This work advances the understanding of c-LLZO formation mechanisms and provides practical insights for optimizing synthesis routes to achieve phase-pure c-LLZO for solid-state battery applications. Full article