材料科学最新文献

Reliable assessment of state of charge (SoC) and state of health (SoH) in commercial batteries remains a major challenge because their closed architecture obscures the underlying electrochemical, structural, and thermal processes, while existing diagnostic methods often provide only indirect, spatially averaged, voltage-based information about battery operation and degradation. Lithium iron phosphate (LFP) is among the most widely deployed cathode materials due to its low cost, long cycle life, and high thermal stability; however, its characteristically flat voltage profile fundamentally limits the information content of conventional diagnostics. In this work, we exploit the large magnetic-susceptibility contrast between the FP and LFP phases and the lithiation-dependent evolution of their phase fractions for accurate and time-efficient determination of SoC in commercial pouch cells and battery packs. Surface-scan magnetic resonance imaging (MRI) provides new SoC and SoH metrics through quantitative inside-out measurements of battery-induced magnetic field perturbations. LFP is a cathode material particularly well suited to this approach because its biphasic FP/LFP regime spans a large fraction of the usable SoC window while generating substantial magnetic susceptibility contrast between the FP and LFP phases. Under the biphasic approximation, the average magnetic susceptibility follows the lever rule, predicting a linear relationship between the induced magnetic field offset and SoC. Surface-scan MRI experiments confirm this prediction over a broad SoC range. We further establish a framework for spatial mapping of SoC and SoH heterogeneity in multi-cell architectures representative of practical battery packs. Despite minimal voltage differences between cells, the method enables quantitative visualization of charge imbalance and structural heterogeneity on the timescale of seconds.

Aqueous ammonium-ion batteries are promising for safety, low cost, and fast energy storage. However, the influence of electrode surface chemistry on NH₄⁺ storage remains poorly understood. Two-dimensional Ti₃C₂T_x MXene, with metallic conductivity, tunable interlayer spacing, and abundant surface terminations, serves as an ideal platform to elucidate NH₄⁺ storage mechanisms. Herein, the role of MXene surface termination in regulating NH₄⁺ storage behavior is systematically investigated using density functional theory calculations and experimental validation. The calculations reveal that the –N terminations offer moderate NH₄⁺ adsorption and high electronic conductivity for rapid charge transfer and ion transport, whereas the –O terminations exhibit stronger ion affinity and enhanced surface stability. Importantly, the mixed –N/–O terminations effectively balance adsorption strength and transition-state stabilization, resulting in the lowest NH₄⁺ migration barrier among the modeled pathways. The calculations employ idealized vacuum-separated surfaces with isolated NH₄⁺ and do not explicitly include solvation or electrolyte effects. Guided by these findings, a mixed –N/–O terminated Ti₃C₂T_x MXene is constructed via a urea-assisted hydrothermal strategy. The optimized NTC-20 electrode delivers 107 mAh g^–1 at 1 A g^–1, retains 67% capacity at 10 A g^–1, and maintains 91% capacity after 10,000 cycles. Ex situ XRD, XPS, and FTIR analyses are consistent with reversible NH₄⁺-associated changes in the local chemical environment and possible storage involving Ti–N···H–N and Ti–O···H–N interactions. Furthermore, the NTC-20//MnO₂/CNTs full cell achieves an energy density of 26.7 Wh kg^–1 at 1.3 kW kg^–1. The results support a dominant role for mixed –N/–O terminations in regulating NH₄⁺ adsorption and diffusion, providing insights into surface-termination engineering for high-performance AAIBs.

Immunoassays and antibody–drug conjugates (ADCs) rely on specific antigen–antibody recognition for biomarker detection and targeted cancer therapy; however, their practical performance is often hampered by low antigen abundance, which yields weak readout signals or insufficient local drug concentrations. Autocatalytic bioorthogonal reactions offer an attractive route to achieve exponential signal amplification, but existing CuAAC-based autocatalytic systems suffer from slow multistep ligand assembly and fluorophore self-quenching that degrade signal-to-background ratios. Herein, we report a next-generation autocatalysis-integrated bioorthogonal catalyst-linked immunosorbent assay (BCLISA) employing bis(triazolylmethyl)aminopropyne (DTTA) as a key autocatalytic precursor. Unlike the prior tripropargylamine (TPA) system that demands three successive CuAAC events for ligand formation, DTTA assembles active tris(triazolylmethyl)amine ligands via only one single CuAAC reaction with 7-azidocoumarin (7AC), incorporating merely one coumarin moiety per ligand to mitigate fluorescence self-quenching. Benefiting from accelerated kinetics and suppressed self-quenching, DTTA-mediated autocatalysis enables sensitive in vitro detection of recombinant HER2 and BK polyomavirus VP1 antigens, outperforming commercial ELISA kits. Functionalized with n-octyl lipid tails, DTTA-C8 anchors autocatalytic cascades onto living cell membranes, allowing confocal imaging and quantitative measurement of low-abundance cell-surface antigens free from endogenous enzyme interference. Furthermore, autocatalytically generated copper catalytic centers drive local CuAAC-mediated prodrug cyclization to produce cytotoxic agents. Distinct from conventional ADC approaches that pursue high drug-to-antibody ratios, our strategy achieves targeted in situ drug activation without heavy antibody modification, retaining native antibody-binding capacity and eliciting antigen-selective cancer-cell death. This work illustrates the utility of rationally optimized autocatalytic bioorthogonal cascades to couple antibody-based molecular recognition with exponential chemical amplification for both diagnostic and therapeutic applications.

S-scheme heterojunction engineering has emerged as an effective strategy for enhancing photocatalytic NO removal by facilitating charge separation while maintaining strong redox capability. Herein, an S-scheme heterojunction consisting of S-doped TiO₂ nanotubes and g-C₃N₄ was successfully constructed via an annealing-assisted interfacial engineering strategy. Comprehensive band structure analyses using Mott–Schottky measurements, valence band X-ray photoelectron spectroscopy, and Kelvin probe force microscopy confirmed the formation of an S-scheme heterojunction between S-TiO₂ and g-C₃N₄. The experimental results revealed a favorable band alignment and the establishment of an interfacial built-in electric field between S-TiO₂ and g-C₃N₄, facilitating S-scheme charge transfer across the heterointerface and preserving highly reactive electrons and holes with strong reduction and oxidation capabilities, respectively, thereby promoting the generation of ^·O₂^– and ^·OH radicals. As a result, the optimized g-C₃N₄/S-doped TiO₂ nanotube photocatalyst achieved an NO removal efficiency of 74.6%, higher than those of pristine S-TiO₂ (43.4%) and g-C₃N₄ (53.4%), while also suppressing NO₂ intermediate formation compared with previously reported TiO₂- and g-C₃N₄-based heterojunctions. This work provides insight into the synergistic role of band alignment, interfacial built-in electric field, and S-scheme charge transfer in boosting photocatalytic NO removal performance.

Acute kidney injury (AKI) is a life-threatening syndrome in which oxidative stress, ferroptosis, and inflammatory amplification converge to damage renal proximal tubular epithelial cells. Although antioxidant and antiferroptotic therapies are conceptually attractive, their efficacy is restricted by rapid clearance and insufficient accumulation in injured renal tubules. Here, we report lysozyme-associated quercetin–manganese metal–phenolic nanocomposites (QMLNCs) as a kidney-targeted therapeutic platform for AKI. In this design, quercetin (QCT) functions simultaneously as an antioxidant drug and a phenolic coordination ligand, while Mn²⁺ participates in metal–phenolic network formation. Lysozyme is incorporated through noncovalent protein–polyphenol interactions to enhance megalin-mediated uptake by proximal tubular cells. QMLNCs exhibited favorable colloidal stability, H₂O₂-responsive release, and broad-spectrum radical-scavenging ability. In cisplatin-injured human kidney 2 (HK-2) cells, QMLNCs reduced Fe²⁺ and reactive oxygen species (ROS) accumulation, preserved mitochondrial membrane potential. Mechanistically, Western blot analysis indicated that QMLNCs could restore the protein levels of SLC7A11, GPX4, and FTH-1, which are key mediators of ferroptosis resistance. In macrophages, QMLNCs suppressed M1 polarization, promoted M2 polarization, and reduced tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and nitric oxide (NO) production. In vivo, QMLNCs preferentially accumulated in injured kidneys and significantly alleviated renal dysfunction in both glycerol-induced and cisplatin-induced AKI models, as indicated by decreased serum creatinine, blood urea nitrogen, MDA and pro-inflammatory cytokines. Overall, QMLNCs integrate renal tubular targeting, ROS scavenging, ferroptosis inhibition, and inflammation modulation into a single metal-natural product nanoplatform, offering a promising strategy for multimodal AKI therapy.

Methicillin-resistant Staphylococcus aureus (MRSA)-infected wounds remain difficult to treat because of antibiotic resistance, biofilm formation, and persistent inflammation, highlighting the need for alternative local antibacterial strategies. Herein, we developed a platinum-based nanozyme (FmY@Pt) through a UV-assisted green reduction process using a tyrosine-containing short peptide (FmY) and evaluated its antibacterial activity and therapeutic potential for treating MRSA-infected wounds. The physicochemical properties and peroxidase(POD)-like activity of FmY@Pt were characterized, and its antibacterial effects and possible mechanisms were evaluated in vitro. The resulting nanozyme exhibited peroxidase-like activity under the tested conditions. In vitro experiments showed that FmY@Pt disrupted bacterial membranes and increased intracellular reactive oxygen species (ROS) levels in MRSA cells. These effects were associated with the antibacterial activity of FmY@Pt. In a mouse model of MRSA-infected skin wounds, the FmY@Pt + H₂O₂ treatment accelerated wound closure, with the wound closure rate reached approximately 80.8% on day 7. Moreover, bacterial survival rate was reduced to approximately 6.13%, corresponding to a reduction of approximately 93.87% relative to the control group. The treatment was also associated with attenuated inflammatory responses and improvements in tissue repair-related histological indicators. These findings suggest that the antibacterial and inflammation-modulating effects of FmY@Pt may collectively contribute to wound repair under the conditions. This study provides experimental evidence supporting the further investigation of nanozyme-based strategies for the treatment of infected wounds.

Cu-modified CeO₂(100) (Cu/CeO₂(100)) has been widely studied for NH₃-selective catalytic oxidation (NH₃-SCO), although most previous theoretical studies considered predefined Cu single atoms, Cu clusters, or CuO_x species, leaving the oxygen-induced reconstruction of the active Cu/CeO₂ surface and its catalytic effect unclear. Here, we employ density functional theory calculations with on-site Coulomb interaction corrections (DFT + U) to identify the stable reconstructed Cu/CeO₂(100) under O₂-rich conditions and elucidate the complete NH₃ oxidation pathways. The calculations reveal that the unique “pocket-like” reconstructed CeO₂(100) surface can drive the aggregation of the isolated Cu atoms into a stable Cu₃O₂ cluster within the pocket area. This restructuring generates active motifs comprising geometrically flexible CuO₄ units and adjacent Ce³⁺ sites, and each CuO₄ unit can facilitate the heterolytic NH₃ dissociation to NH₂*, while the Ce³⁺ site can activate O₂ into superoxide (⁠$O_2^{–}$⁠) species. The activated $O_2^{–}$ species then reacts with NH₂* to form stable NH₂O* and O* intermediates. Moreover, a cooperative dynamic restructuring between NH₂O* and nearby O* species gives rise to a distinctive Ce─O─NH_x···O five-membered ring. This unique configuration enables a nearly barrierless (0.02 eV) proton transfer to produce NHO* and OH* species, ultimately driving the deep oxidation to form NO* and H₂O*. These findings reveal a previously unrecognized pocket-confinement effect on Cu aggregation and redox-site cooperation on Cu/CeO₂(100), providing mechanistic guidance for the rational design of Cu/CeO₂-based NH₃-SCO catalysts under oxygen-rich conditions.