Journal of Materials Science最新文献

High impedance caused by insufficient electrode/electrolyte interfacial compatibility has long been a core challenge for solid-state lithium metal batteries. To optimize the overall interfacial structure, a synergistic strategy must address both the positive and negative electrodes. In this study, a dual in situ cured solid-state polymer electrolyte (DIC-SPE) technique was developed through in situ curing of both the cathode/electrolyte and the lithium metal anode/electrolyte interface. The prepared solid-state electrolyte exhibits an ionic conductivity of 0.12 mS·cm⁻¹ and an electrochemical stability window as high as 5.0 V. The as-assembled lithium symmetric battery achieves stable cycling for 400 h at a current density of 0.2 mA·cm⁻², indicating a favorable suppression for lithium dendrite growth due to the in situ cured anode/solid electrolyte surface. Rate performance and long-cycle tests demonstrate that the LFP/DIC-SPE/Li battery exhibits superior stability compared to ex situ preparation processes: At 30 °C, DIC-SPE cell maintains 81.1% capacity retention after 400 cycles at 0.5 C and 91.7% capacity retention after 200 cycles at 1 C. The dual in situ solid-state electrolyte preparation strategy proposed in this study provides a new technical pathway for the development of high-performance and cycling stability solid-state lithium batteries.

Graphical Abstract

Nickel-based alloys, such as Inconel 718 (IN718), are widely used in the aerospace industry due to their excellent mechanical strength, oxidation resistance, and thermal stability at elevated temperatures. However, despite their superior high-temperature performance, understanding their friction and wear behavior under varying temperature conditions remains crucial for improving component life and efficiency. In this context, the present study investigates the influence of temperature on the friction and wear mechanisms of IN718 when sliding against an alumina counterface. Experiments were conducted using a high temperature ball-on-flat reciprocating apparatus. The results showed that the coefficient of friction (CoF) of IN718 remained nearly identical with varying temperature up to 450 °C. However, the wear rate for the IN718 alloy increased with increasing temperature. To better understand this behavior, the emphasis of this study was placed on the correlation between the tribological behaviour of the Ni-based alloy and the third body formation process, characterized using micro-Raman and scanning electron microscopy (SEM). The analyses indicated the formation of randomly distributed oxide patches of Cr₂O₃ and Fe₂O₃ along with wear debris particles, which contributed to enhanced abrasive wear. As the temperature increased, the formation of these abrasive oxide particles led to severe wear on both the IN718 surface and the alumina counterface.

The long-term mechanical properties of 316H stainless steel at 700 °C are of great concern for its application in the fourth-generation nuclear power plant. To this end, the effect of long-term aging on the mechanical properties is systematically analyzed. A series of hardness, tensile, and impact tests are conducted on the material aged for six different aging times at 700 °C, that is, 0 h, 1338 h, 2544 h, 3624 h, 5050 h, and 10,165 h. Combined with microstructural characterization, the evolution of microstructure and its influence on the mechanical response are elucidated. Results show that, with increasing aging time, both hardness and yield strength increase monotonically, while ultimate tensile strength decreases at 1338 h and then increases to exceed that of the unaged condition. Moreover, impact toughness declines markedly. Microstructural observations indicate that the evolution is governed by precipitation rather than by grain coarsening. M₂₃C₆ carbides preferentially grow along grain and twin boundaries and extend into the grain interior, and a scattered Laves phase appears during prolonged aging. The evolution of precipitates impedes the motion of dislocations and grain boundaries, which raises the hardness while degrading the toughness. The hardness, precipitate area fraction, and their product are found to follow a linear relationship with impact energy on the log–log scale, with the hardness performing the best, followed by the product and then by the precipitate area fraction. Accordingly, the hardness can be used uniquely for the prediction of impact energy after different aging times.

In this study, a temperature-controlled terahertz metamaterial demultiplexer based on the phase-change characteristics of vanadium dioxide (VO₂) is proposed. The device is designed with a three-layer structure: The top layer is a reflection layer containing a metal resonator and a double ‘C’-shaped phase-change resonator ring; the middle layer is a polyimide dielectric layer; and the bottom layer consists of three inter-nested two-metal open resonator rings and an inner ring of VO₂ thermally modulated ring. The device achieves efficient separation of three independent terahertz bands, 0.47 THz, 0.52 THz and 0.54 THz, and demonstrates temperature-dependent switching between the 0.47 THz and high-frequency channels. The demultiplexer exhibits high isolation of more than -20 dB with less than 1 dB insertion loss at all target frequencies. Its synergistic characteristics of low insertion loss and excellent channel isolation meet the critical performance requirements of advanced terahertz communication systems. This dynamically tunable design based on VO₂ provides a new idea for frequency tuning of terahertz devices and shows significant application potential in the field of multi-functional photonic integration.

In this study, a La-doped flexible hydrophobic Al₂O₃ fiber membrane was fabricated via electrospinning technology, and the influence of La doping on the mechanical properties and surface wettability of the Al₂O₃ fiber membrane was systematically investigated. The results showed that the La-doped modified alumina nanofiber membrane has tunable fiber diameters (180–480 nm) and a highly interconnected porous network, which enhanced the efficiency and flux of oil–water separation. The incorporating an appropriate amount of rare earth La atoms, specifically at a La/Al atomic ratio of 0.125 (La-Al₂O₃-2), effectively enhanced the flexibility and tensile strength of the membrane. Concurrently, hydrophobic La₂O₃ formed on the fiber surface, which transformed the membrane from hydrophilic to hydrophobic. As a result, the La-doped Al₂O₃ membrane exhibited excellent anti-fouling performance, high permeation flux, and efficient oil–water separation. However, excessive La addition led to a significant decline in the flexibility and tensile strength of the Al₂O₃ fiber membrane, whereas the hydrophobic surface was largely preserved. Among all samples, the La-Al₂O₃-2 fiber membrane exhibited superior flexibility and tensile strength. In oil–water separation applications, it achieved a high permeation flux of 2921 L/(m² ·h) and a separation efficiency of 98.4%; meanwhile, the good reusability was also obtained.

Graphical abstract

The outstanding properties of perovskite oxide materials have attained significant attention for energy conversion and storage applications. A series of polycrystalline La_0.6Sr_0.4Co_1-xB_xO₃ (0 ≤ x ≤ 0.8) (B = Ni, Fe, Cu, Cr) perovskite oxide materials have been fabricated by Pechini modified sol–gel method at 750 °C with gradual doping of different cations on B-site. A detailed examination of the compositional impacts on the structure, optical, dielectric and electrical properties that characterize the fundamental physics has been carried out in this work. The lattice parameters are observed to increase with the decrease in Co contents due to the difference in ionic radii of the substituted B-site cations. With the moderate Tafel slope and low overpotential of 290 mV and 305 mV at 10 mAcm⁻², the respective La_0.6Sr_0.4Co_0.6Ni_0.2Fe_0.2O₃ and La_0.6Sr_0.4Co_0.2Ni_0.2Fe_0.2Cu_0.2Cr_0.2O₃ materials have demonstrated exceptional oxygen evolution reaction (OER) catalytic activity, making them suitable for energy storage devices. Dielectric constant (єʹ, єʹʹ) and tangent loss decrease as the applied frequency increases. The impedance Zʹ ranges from minimum of 537 Ω to the maximum of 10,022 Ω and leads to the applications in sensor technology, supercapacitors, electrochemical devices and dielectric filters. Grain boundary conduction was evaluated using Nyquist and Cole–Cole plots, along with Randles circuit study. The higher values of optical bandgaps (3.21–3.71 eV) and (2.89–3.28 eV) find applications in photocatalysis, optoelectronic devices and UV photodetectors. It is observed that Urbach energy ranges from 564–1163 meV with transition of B-site cations. Moreover, I-V measurement at room temperature indicated the semiconducting type behavior of La_0.6Sr_0.4Co_0.2Ni_0.2Fe_0.2Cu_0.2Cr_0.2O₃ high entropy perovskite oxide composition.

The carbon dioxide (CO₂) transformation into beneficial fuels or chemicals by photoelectrocatalytic (PeC) reaction has been proved sustainable. As a standalone or component in composites, the graphitic carbon nitride (g-C₃N₄) catalysts were significantly utilized for PeC approaches. In this research work, as a first instance, a sustainable green approach of simple hydrothermal treatment at various temperatures, such as 90, 120, 150, and 180 °C, was adopted to synthesize g-C₃N₄ (xgCN) catalysts to enrich their PeC CO₂ reduction into methanol activity. The simple hydrothermal treatment achieved increased stacking layer distance of g-C₃N₄ and fine-tuning of the band gap. The 120gCN catalyst (treated at 120 °C) exhibited a superior current at − 1.0 V of 3.62 mA cm⁻² and a 4.39 µmol L⁻¹ h⁻¹ cm⁻² methanol generation in PeC CO₂ reduction reaction, which was around twofold superior compared to that of PgCN (untreated g-C₃N₄) catalyst. The excellent efficiency of the 120gCN catalyst was credited to its better production and lesser electron (e⁻)-hole (h⁺) pairs recombination rate.

The surface integrity and fretting fatigue behavior of Ti6Al4V dovetail structure treated by shot peening (SP), salt spray corrosion (SS) and shot peening combined with salt spray corrosion (SP+SS), respectively, were studied. The findings indicate that SP introduces residual compressive stress (RCS) layer and hardened layer. The SS causes the development of pitting pits and corrosion products, also induces localized pitting corrosion in SP samples, triggering the release of RCS introduced by SP. Compared with AS samples, the fatigue lifetime of SP and SS samples are, respectively, increased and decreased, and the cracks initiation and propagation mechanisms are changed. Compared with SP samples, the fatigue lifetime of SP+SS samples was reduced but the fatigue damage mechanism did not change. SP treatment benefits from the plastic deformation caused by surface dislocations, which improves the crack initiation life. SS treatment generates the corrosion pits of surface, manifested as notch effect and reduces the crack initiation life.

Cu-based metal–organic frameworks (MOFs) have demonstrated promising potential for electrochemical CO₂ reduction reaction (CO₂RR) toward CH₄ production. However, achieving high CH₄ selectivity under industrial-level current densities remains challenging. Although high-valent Cu species are favorable for CH₄ generation, the reduction of Cu during the CO₂RR process is inevitable. In this work, an Al-doped CuAl-BTC catalyst was successfully synthesized by incorporating the strongly oxyphilic metal Al. X-ray photoelectron spectroscopy (XPS) results reveal that the introduction of Al effectively suppresses the reduction of Cu, preserving more Cu²⁺ sites and enhancing the adsorption of the *CO intermediate. At 500 mA cm⁻², the as-prepared CuAl-BTC catalyst exhibits a faradaic efficiency (FE) of 79.1% for methane, which is 1.5 times higher than that of Cu-BTC. In situ Raman and infrared spectroscopy analyses further demonstrate that the stronger adsorption of the *CO intermediate on the CuAl-BTC catalyst accelerated its protonation process, which in turn promoted the conversion of CO₂ to CH₄. These findings propose a strategy of stabilizing high-valent Cu sites via oxyphilic metals to enhance key intermediate adsorption, offering a new avenue for efficient electrocatalytic CO₂ reduction to CH₄.

The hybrid nanocomposites advancements are crucial to the medicinal applications with biocompatible behavior. This work demonstrates the preparation of different chitosan-based nanocomposites of CS/rGO (NC-1), CS/rGO/HA (NC-2), CS/rGO/HA/CeO₂ (NC-3), and CS/rGO/HA/CeO₂/PMMA (NC-4) for the biological applications. A cost-effective and straightforward chemical methodology was used for their synthesis. The structural and optical characteristics of the synthesized nanocomposites were thoroughly examined using Fourier transform infrared spectroscopy, X-ray diffraction, and UV–Vis analyses. Morphological imaging revealed modified surface properties and a quasi-spherical structure with agglomerated grains in the prepared nanocomposites. The biological and therapeutic effects of these composites were assessed through antibacterial, cytocompatibility, and wound healing studies. Notably, the NC-3 and NC-4 nanocomposites exhibited enhanced antibacterial activity against both gram-negative (P. aeruginosa and E. coli) and gram-positive (S. aureus and B. subtilis) microorganisms. Cell viability assessments on MG-63 osteoblast cells indicated improved cell adhesion with the NC-4 composites. Furthermore, the in vitro wound scratch assay demonstrated that the NC-4 nanocomposite significantly promoted cell proliferation and migration, effectively facilitating wound healing within 48 h. Thus, the NC-4 nanocomposite emerges as a promising candidate for antibacterial and bone regenerative applications.