Science China Materials最新文献

Tensile stress annealing (TSA) is an effective strategy for tailoring magnetic anisotropy and high-frequency performance in nanocrystalline soft magnetic alloys. Here, we systematically investigate the influence of TSA on the microstructure, magnetic domain evolution, and permeability stability of Fe_69.5Co₃Nb₂Mo_1.5Si₁₄B₉Cu₁ nanocrystalline alloys. Across all applied stresses (0–300 MPa), the alloys retain an ultrafine grain size (⩽11 nm), yet the induced uniaxial anisotropy constant (K_u) rises sharply from 22.5 to 665 J/m³. This increase in K_u refines the magnetic domain structure, reducing average domain width from 110 to 36 µm, and shifts the magnetization mechanism from domain-wall displacement to rotation-dominated reversal. Quantitative correlation between K_u, domain structure, and effective permeability (μ_e) reveals that higher stress suppresses μ_e at low frequencies but yields exceptional frequency stability: μ_e ≈ 2330 is maintained up to 1 MHz at 50 MPa, and μ_e ≈ 585 remains constant from 1 kHz to 10 MHz at 300 MPa. These findings demonstrate that stress-induced anisotropy is a decisive factor in governing high-frequency magnetic response, offering both mechanistic insight and a practical framework for designing next-generation soft magnetic materials for precision current transformers, EMC filters, and MHz-class power electronics.

Transition metal nitrides (TMNs) have been considered as promising alternative catalysts to noble metals in various electrocatalytic applications due to their noble metal-like electronic structures, high conductivity, low cost, as well as strong chemical stability, which could resist corrosion and oxidation in harsh operation conditions. Therefore, the rational design and controlled synthesis of TMNs with distinct structures play a vital role in developing highly efficient electrocatalysts toward electrochemical applications. This review provides a comprehensive summary of representative synthetic strategies for TMNs, such as direct nitridation, solid-state reaction, sol-gel assisted reaction, and wet-chemical reaction, presents the distinct structural characterizations, and demonstrates their advances in the electrochemical applications. Finally, we propose the remaining challenges and the future research directions on the exploration of TMNs with well-defined structures for electrocatalytic applications, which could shed light on the future development of high-performance electrocatalysts.

Flexible energy storage and harvesting devices, as core components of the flexible electronic system, have driven the transformation of electronic system from “external power supply” to “self-powering” and from “fixed forms” to “adaptive configurations”, thus playing an important role in the advancement of wearable technology, the internet of things, and other related fields. MXenes, a class of two-dimensional transition metal carbides, nitrides, and carbonitrides, emerge as promising candidates for flexible energy storage and harvesting devices, attributed to their excellent conductivity, mechanical flexibility, and tunable interfacial characteristics. Specifically, the interfacial characteristics of MXenes, including surface energy, surface terminations, and interlayer spacing, have a decisive influence on the performance of MXene-based energy devices. This review summarizes the influence of microcosmic interfacial characteristics on macroscopic properties, the interfacial regulation strategies, and applications in flexible energy storage and harvesting of MXenes, concluding with current challenges and perspectives to guide the design of high-performance MXene-based energy devices.

Air-permeable and ultrathin conductive electrodes are essential for next-generation soft electronics, including breathable wearables, on-skin devices and bio-integrated electronics. However, conventional metallization strategies, such as sputtering and ink-printing, often suffer from severe vertical charge leakage due to the porous and ultrathin characteristics of nanofibrous networks, leading to device short-circuiting, operational failure and limited vertical integration. Here, we present a solvent-selective dissolution-assisted transfer printing strategy to achieve surface-confined metallization of ultrathin, lightweight, and gas-permeable nanofibrous networks, enabling lateral conductivity while maintaining vertical insulation. This transfer printing process facilitates not only the rapid formation of conductive patterns on the surface of nanofibrous networks but also mechanical reinforcement through solvent evaporation-induced interlocked fiber-fiber welding. Meanwhile, the strategy preserves the high permeability of the nanofibrous networks and imparts a unique combination of surface conductivity (2 Ω cm) and vertical insulativity (10¹¹ Ω cm). The resulting anisotropic conductive networks enable low-voltage wearable heaters, high-sensitive pressure sensors, and ultralight temperature sensors. A pressure-temperature dual-modal sensing patch is further fabricated for intelligent grasping classification. The proposed surface-confined metallization strategy enables rapid fabrication of an anisotropic conductive network as a building block to construct air-permeable, ultrathin and lightweight wearable electronics.

The development of high-performance bifunctional electrocatalysts is crucial for advancing zinc-air batteries. However, the fundamentally distinct mechanisms of the oxygen reduction and evolution reactions (ORR/OER) hinder the simultaneous realization of high activity within a single catalyst. Herein, we propose a spatial decoupling strategy to overcome this limitation by engineering isolated Fe single-atoms and Fe–Ir dual-atom pairs on a nitrogen-doped carbon matrix (Fe/FeIr-NC). In this architecture, Fe single atoms serve as ORR centers, while Fe–Ir pairs with tunable spacing are tailored for OER, enabling complete functional separation and independent optimization of the reactions. As a result, the catalyst delivers an ORR half-wave potential of 0.91 V and an OER overpotential of 250 mV at 10 mA cm⁻², yielding a record-low bifunctional gap (ΔE = 0.57 V) that outperforms all reported single- and dual-atom catalysts. A flexible fiber zinc-air battery was developed based on this catalyst, delivering a peak power density of 3920 W kg⁻¹, along with a 1.4-fold increase in energy efficiency and a 2.6-fold extension in cycle life compared to the commercial Pt/C + IrO₂ benchmark. This work not only breaks the traditional activity trade-off in bi-functional catalysis but also offers a promising route toward high-performance power sources for wearable electronics.

Fiber photodetectors (FPDs) with high deformability, flexible designability, and seamless integrability with everyday textiles hold tremendous potential for the next-generation wearable optoelectronics. Inorganic semiconductors (ISCs) are considered the ideal building block to design and govern the functions of FPDs owing to their superior electrical and optical properties. Recent developments in wearable technology of ISCs, especially in fiber form factor, have driven the creation of various FPDs with smart capabilities, from light sensing, information interfacing, to sophisticated logic operating, revolutionizing human-machine interaction paradigms in many emerging fields. Herein, we present a comprehensive review of the recent progress of ISC-based FPDs. Firstly, key design principles for ISC-based FPDs are explored, encompassing material selection, fabrication technologies, device architectures, and textile integration strategies. Then, how defect engineering, alignment engineering, and heterojunction engineering of ISCs can control the optoelectronic performance of FPDs is examined. Following this, potential wearable applications of ISC-based FPDs in optical communication, image sensing, and health monitoring are analyzed. Finally, the challenges and perspectives for the design of high-performance ISC-based FPDs are outlined.

The development of bifunctional electrocatalysts capable of integrating biomass-derived platform molecule oxidation with organic reduction offers a promising strategy for simultaneously enhancing energy efficiency and generating high-value chemicals. However, designing catalysts that exhibit both high activity and stability in integrated systems remains a significant challenge. Herein, we report a self-supported electrode composed of nitrogen-doped carbonized wood (NCW) supported NiCo nanosheets (NiCo_0.3/NCW) that enables the electrocatalytic 5-hydroxymethylfurfural oxidation to produce 2,5-furandicarboxylic acid (FDCA) and the nitrobenzene reduction to yield aniline in an integrated electrochemical cell. The NiCo_0.3/NCW electrode achieves the production of FDCA and aniline at a low cell voltage of 1.7 V, with ∼99% anodic and ∼92% cathodic Faradaic efficiencies, respectively. Experimental characterizations disclose that the hierarchical porous NCW architecture promotes the dispersion of active sites, while nitrogen doping strengthens metal-support interactions. In-situ spectroscopic experiments combined with density functional theory (DFT) calculations reveal that cobalt incorporation tunes the electronic structure of nickel, thus optimizing substrate and intermediate adsorption, and lowering energy barriers. These effects ultimately enhance the performance of the natural wood-derived catalyst in integrated biomass valorization and selective organic electrosynthesis.

Real-time health monitoring and ongoing evaluation of physiological conditions are becoming increasingly vital for the advancement of future medical diagnostics and personalized healthcare solutions. Given that certain illnesses necessitate prompt and accessible detection methods, wearable chemical sensors have garnered considerable interest for their capability to monitor health through physiological signals and chemical indicators. This review delivers a thorough examination of recent developments in four primary categories of wearable chemical sensors: biosensors, humidity sensors, gas sensors, and ion sensors. We explore the representative materials, device structures, operating mechanisms, and various application scenarios for each type of sensor. By investigating the latest innovations in these technologies, we aim to provide a detailed overview of the current research landscape, highlight existing challenges, and present potential future directions of wearable chemical sensors in healthcare monitoring.

Converting body heat into electricity presents an appealing route for sustainably powering wearable electronics; however, conventional thermoelectric materials face significant drawbacks, including high ionic concentrations, toxicity, and limited thermoelectric efficiency. Here, we report an ionic thermoelectric hydrogel designed through precise supramolecular chemistry, utilizing dual molecular interactions, host-guest complexation of α-cyclodextrin (α-CD) with I₃⁻ ions and hydrogen bonding between polyvinyl alcohol (PVA) polymer chains and I₃⁻. This molecularly tailored approach markedly amplifies thermoelectric performance, achieving a high thermopower of 2.21 mV/K and a tenfold enhancement in peak power output at an exceptionally low iodine concentration (10 mmol/L I⁻ + 2.5 mmol/L I₃⁻). The hydrogel maintains excellent biocompatibility and mechanical robustness, suitable for direct skin contact. Demonstrated applications include flexible thermoelectric devices generating nearly 100 mV from body heat and sensor arrays capable of motion and spatial temperature sensing. These results underscore the substantial potential of supramolecularly designed ionic thermoelectric hydrogels for wearable energy harvesting, personalized healthcare monitoring, and advanced human-computer interfaces.

Growing demand for sustainable, high-performance materials is driving research to replace petroleum-based plastics with abundant biomass, especially cellulose. However, the effective modification and functionalization of cellulose is often impeded by complex processing requirements and limited performance tunability. Here, an innovative “active” green medium strategy based on an ethyl cellulose/thymol eutectic system is reported, enabling in situ chemical modification of eutectic components and the construction of dynamic self-adaptive networks without external catalysts or initiators. Through precise molecular design, dynamic boroxine networks and acrylate crosslinking networks are synergistically integrated into the cellulosic bioplastic (CBP) matrix. The resulting CBP-A₂B₈ exhibits exceptional optical transparency (∼85%), superior mechanical properties (tensile strength ∼30 MPa), facile thermal processability, and closed-loop recyclability. Its chemical structure and mechanical performance remain highly stable even after 20 hot-compression recycling cycles. Complete biodegradation occurs under natural environmental conditions within approximately 100 days. Furthermore, the bioplastic, when combined with silver nanowires, forms high-performance flexible transparent conductive films successfully applied in customizable electroluminescent devices. Post-lifecycle, device components (silver nanowires and CBP matrix) are efficiently separated and recycled using a straightforward solvent-based method. This eutectic system-mediated strategy offers a novel pathway for the development of sustainable, high-performance bioplastics with a closed-loop lifecycle.