Science China Materials最新文献

Sluggish water dissociation kinetics in the alkaline hydrogen evolution reaction (HER) continue to hamper its practical production. Herein, a class of heterojunction electrocatalyst featuring Ru-Ni(OH)₂ interfaces on nickel foam (NF) with self-engineered built-in electric fields (BIEF) has been synthesized via a simple in situ galvanic replacement reaction. The as-made hierarchical architecture of Ru-Ni (OH)₂/NF exhibits a record overpotential of 9.6 mV at a current density of 10 mA cm⁻² for alkaline HER, surpassing most reported catalysts and the commercial Pt/C benchmark. Furthermore, it also reveals exceptional catalytic activity towards hydrazine oxidation reaction (HzOR) at 100 mA cm⁻² with a remarkably low potential of ca. 0.015 V vs. RHE (reversible hydrogen electrode). The assembled overall hydrazine splitting (OHzS) system integrating HER and HzOR requires a cell voltage of about 0.09 V to reach 50 mA cm⁻², which is 1.637 V lower than the corresponding overall water splitting (OWS) device. Systematic analysis and calculation reveal that the BIEF induces the redistribution of interfacial electrons for Ru, facilitating H₂O dissociation and intermediates conversion to deliver the ultra-high electrocatalytic performance. This work provides an avenue for the design and preparation of electric field-mediated catalysts towards sustainable energy conversion.

Piezoelectric materials can convert mechanical energy into electrical signals, making them highly applicable in sensors, actuators, and energy harvesting systems. Although traditional inorganic piezoelectric ceramics (e.g., PZT and BTO) exhibit excellent piezoelectric properties, their brittleness significantly limits their use in flexible electronic devices. Herein, we fabricated PZT@carboxymethyl chitosan (CMCS)/thermoplastic polyurethane (TPU) porous composite used as flexible piezoelectric materials. The core-shell structure of PZT@CMCS improves interfacial compatibility with the polymer matrix. Meanwhile, the porous skeleton structure of the TPU matrix facilitates stress transfer and amplification, achieving a large piezoelectric composited content and enhancing piezoelectric output. Thus, PZT@CMCS/TPU piezoelectric devices in this work achieve remarkable output voltage (53 V), current (13 µA), showing an 11-fold increase in piezoelectric output performance compared to conventional PZT composite films. Enabling the application of PZT composite materials in flexible piezoelectric devices.

Respiratory sensors, capable of monitoring human respiratory status, are essential for health management, disease prevention, and early diagnosis. Achieving real-time monitoring of respiratory status requires sensors with fast and sensitive respiratory response, as well as high stability. Herein, we demonstrate an amino-modified graphdiyne (NH₂-GDY)-based sensor for real-time monitoring of human respiratory status. Compared to pristine graphdiyne, the amino-functionalized NH₂-GDY exhibits enhanced adsorption capacity for water molecules. Furthermore, its enlarged nanoporous structure facilitates the migration of water molecules, enabling rapid adsorption/desorption of water molecules. This respiratory sensor demonstrates ultra-fast and ultra-sensitive respiratory responses, coupled with remarkable flexibility and stability. When integrated into a wearable electronic system, it achieves real-time monitoring of sleep apnea syndrome. This work highlights the feasibility of novel carbon-based respiratory sensors in advanced health monitoring applications.

Deep learning-enhanced pressure sensors integrate signal processing and sensing capabilities, offering transformative potential in wearable electronics. However, current deep learning-based pressure sensors primarily use petroleum-based polymers for the sensing/encapsulating layers and metallic electrodes. This results in limited biodegradability, poor biocompatibility, and insufficient breathability. Here, we present an all-textile-based pressure sensor that combines tunable-conductivity polypyrrole textiles for the electrode and sensing layers with real-time artificial intelligence algorithms. Eliminating the constraints of metallic electrodes and petroleum-based polymers results in an entire device that exhibits excellent biocompatibility, biodegradability, and breathability. Moreover, the textile sensing layer’s structure ensures pressure-induced conductivity, contributing to high sensitivity and a wide detection range. Based on these high-performance and comfortable textiles, we demonstrate intelligent applications such as health monitoring, software/hardware control, and complex human motion analysis. Our work paves the way for sustainable, breathable, and biocompatible next-generation smart textiles, enabling the development of intelligent and eco-conscious electronic systems.

The achievement of electrically pumped lasers with smaller and more compact physical dimensions is expected to be crucial for future optical information processing, optical storage, and photonic integrated circuits. However, developing laser devices upon electrical injection remains challenging due to stability issues, significant non-radiative losses, and severe Joule heating effects. Herein, we exhibit an ultralow-threshold low-dimensional perovskite microlaser coated with Au nanoparticles (AuNPs), which enables the optimization of its lasing properties upon optical pumping synchronized with current injection at ambient temperature. The threshold value is considerably reduced to 8.6 µJ/cm², which is approximately 44% lower than that of the pristine one. The microlaser incorporates size-optimized AuNPs that simultaneously enhance perovskite’s lasing performance and electrical properties, particularly enabling a current injection of approximately 2.98 kA/cm². Besides, AuNPs can accelerate hot-carrier cooling in perovskites, thereby reducing non-radiative recombination losses and mitigating Joule heating effects. The microlaser thresholds show progressive reduction with increasing electrical assist fraction. This study underscores that the ultimate goal of realizing electrically driven perovskite microlasers may eventually become a reality, paving a promising avenue toward the further development of electrically pumped microlaser diodes.

The rapid development of biomedical engineering has laid a solid foundation for integrated healthcare monitoring systems across hospital and ambulatory settings. As a key technology in this field, flexible and wearable bioelectronics, with distinct mechanical compliance and biocompatibility, enable real-time, continuous electrocardiography (ECG) monitoring, offering new possibilities for early diagnosis and personalized treatment of cardiovascular diseases. This review presents a summary of recent advances in flexible and wearable bioelectronics for ECG monitoring from three major perspectives. First, in terms of materials, we highlight the roles of emerging functional materials, such as liquid metals, nanomaterials, and conductive hydrogels, in improving electrical performance and user comfort. Second, for structural design, we discuss strategies including microneedle arrays, bioinspired geometries, and stretchable interconnects to enhance skin-electrode interface stability and adaptability to body motion. Third, at the system level, we analyse the integration of multichannel and multimodal sensing and wireless transmission technologies to support practical ECG applications. Finally, current challenges, including long-term reliability and data security risks, are discussed, and future directions are proposed, including material–structure co-optimization and AI-assisted analysis, to guide the development of next-generation intelligent ECG monitoring systems.

MXene-based layered films show great promise for electromagnetic interference (EMI) shielding, yet maintaining highly ordered structures during large-scale production remains challenging. Herein, we present a facile centrifugal casting method for scalable fabrication of MXene/polyvinyl alcohol (MXene/PVA) films with highly oriented and compact layered structures. During centrifugal casting, the viscous fluid experiences strong shear and centrifugal forces along the tangential and normal directions, respectively, inducing compact and oriented arrangement of MXene nanosheets in the layered structure. Consequently, the Herman’s orientation factor of MXene in composite films shows a significant increase from 0.681 to 0.794 as the rotation rate rises from 0 to 4000 r/min. Accordingly, the tensile strength and toughness of the composite film increase from 55.2 to 191.1 MPa, and from ∼0.8 to 2.5 MJ/m³. More importantly, the highly oriented and compact layered structure with the ultrathin thickness (∼8 µm) enables a high absolute electromagnetic shielding effectiveness (SSE/t) of 21029 dB cm²/g. Moreover, the increased oriented arrangement of MXene in the layered structure can significantly reduce the infrared emissivity to 0.248, thus endowing the MXene/PVA film with excellent thermal camouflage capability. Therefore, this work presents a more effective strategy for constructing high-performance MXene-based layered films.

Converting hydrogels into one-dimensional (1D) fiber structures and integrating them into textiles offers a promising approach for the development of smart wearable devices. However, under repeated deformations, the fracture of low-energy amorphous crosslinking structure in the hydrogel leads to fatigue and hysteresis. This severely impairs the mechanical properties of hydrogel fibers and limits their potential applications. In this study, a novel strategy for fabricating composite hydrogel smart fibers featuring exceptional mechanical robustness and multisensory capabilities is proposed. By integrating an Ecoflex elastomer backbone into the organic hydrogel, the fatigue resistance is enhanced and hysteresis is eliminated, and no significant degradation of mechanical properties is observed after 10,000 cycles of 200% strain loading and unloading. The strain sensor based on this fiber has high sensitivity (gauge factor ∼3.0), fast response (140 ms)/recovery time (130 ms), and excellent repeatability (10,000 cycles at 70% strain). Moreover, the organic hydrogel/Ecoflex fiber (OHEF) exhibits remarkable resistance to dehydration and freezing. Smart textiles based on OHEF can detect diverse external stimuli, including deformation, temperature, proximity, pressure, and can perform passive sensing. The successful development of this fiber represents significant progress in applying hydrogels to wearable devices. Its multisensory properties highlight the great potential of OHEF for wearable electronics applications.