Materials Horizons最新文献

The central challenge in advancing solid-state energy conversion is the discovery of materials capable of decoupling the intrinsically coupled thermoelectric parameters. While existing layered ionic materials, such as hexagonal Mg₃Sb₂, exhibit structural anisotropy, they often lack the requisite directional transport and suffer from imbalanced performance at different doping conditions. To address this limitation, we introduce a general design principle, namely the cation-stabilized monolayer network principle. This strategy conceptually segregates the crystal structure into tunable building blocks, which facilitates the rational engineering of new phases with customized anisotropy. Utilizing this principle, we computationally discovered three novel compound categories: tetragonal C^IC^IIA^V ternaries, tetragonal CII3AV2 binaries, and orthorhombic C^ICII2AV2 ternaries. A systematic high-throughput screening of 370 candidates identified 26 thermodynamically stable materials. We confirm the strong anisotropy in both electron and phonon transport achieved in these phases, exemplified by CsMgBi (a C^IC^IIA^V compound) which demonstrates an ultra-high anisotropy in the directional thermal conductivities of ρ_κ = 3.5. Moreover, the identification of tetragonal β-Mg₃Sb₂ (a CII3AV2 compound) as a superior p-type material addresses a significant performance deficit present in the prevailing hexagonal Mg₃Sb₂. This work validates the charged monolayer stabilization principle as a powerful approach for the rational discovery of novel, highly anisotropic, and high-performance ionic layered thermoelectrics.

Natural anisotropic tissues, such as tendons and cartilages, achieve remarkable mechanical properties and various biofunctions through oriented hierarchical structures. Inspired from organisms, we develop a synergistic molecular and structural engineering technique based on the thermodynamically reversible reconfiguration of hydrogen bonds to achieve high-performance anisotropic supramolecular hydrogels by quenching pre-stretched polymer networks. Multiple inherent hydrogen bonds gradually dissociate under high-temperature processing to allow the good alignment of the polymer chains by uniaxial pre-stretching. The oriented polymer chains are then fixed on-site by rapid quenching-mediated hydrogen bond reconstruction at low temperatures (e.g., ice bath). This process merely relies on the inherent hydrogen bonds of polymer chains instead of traditional salting-out, metal ionic coordination and solvent effects. The optimal anisotropic hydrogel shows a tensile strength of 19.4 ± 0.7 MPa and toughness of 53.8 ± 5.2 MJ m^-3 along the pre-stretching direction, which are 2.6- and 1.7-times higher than that of the unquenched isotropic hydrogels, respectively. This general strategy is applicable to different strong hydrogen bonding supramolecular hydrogel systems. Furthermore, we fabricate anisotropic hydrogel fibers as damping materials. This general approach for the preparation of anisotropic supramolecular hydrogels shows great potential for various engineering applications, such as in the fabrication protective and cushioning materials, flexible optoelectronics, and mechano-functional scaffolds.

Due to their unique mixed ionic-electronic working mechanism and good biocompatibility, organic electrochemical transistors (OECTs) show great potential for applications in bioelectronics and neuromorphic electronics. Compared with the widely adopted floating gate setup, side gate OECTs, with well-defined device geometry and simpler fabrication and testing procedures, which may unleash the potential of OECTs for further integration and commercialization, are still under development. Here, the gate size (S_G) and gate-channel distance (D_GC) of side gates in vertical OECTs are precisely modulated by combining high-resolution printed silver gates and photo-patternable transistor channels. It is demonstrated that the performances of Homo-gDPP-based vOECTs show distinct variation when S_G and D_GC vary from 200 to 1600 µm² and from 500 to 15 µm, respectively, for a channel area of only 30 × 30 µm². Champion on current, peak transconductance, and on/off current ratio values of 13.83 ± 0.54 mA, 87.56 ± 2.76 mS, and (5.21 ± 0.27) × 10⁸ are obtained with an S_G of 1600 µm² and a D_GC of 15 µm, which are among the highest reported for side gate OECTs. Moreover, high-density complementary circuits are integrated in combination with the channel size and S_G control, revealing the fastest switching speed (<9 ms) in reported side gate OECT circuits based on quasi-solid-state electrolytes (PEG-LiCl). This work provides a strategy for the optimal design and performance enhancement of OECTs and demonstrates ways for the miniaturization and integration of next-generation electronics based on OECTs.

Recurrent bacterial invasion delays the healing of infected sites; therefore, the development of a sustained antibacterial therapeutic strategy is essential. Herein, we use one simple multi-stage assembly strategy to develop a Lactobacillus reuteri-capsule patch that could achieve sustained antibacterial applications. The encapsulated strain retains its activity within the sodium alginate (SA) capsule, showing sustained release in response to pH changes in the infection microenvironment. In addition, the nanofiber structure of bacterial cellulose (BC) prevented contact between the strains and the lesion to avoid additional inflammatory reactions (the isolation rate reached 99.9%). The patch exhibited a sustained antibacterial effect against the formation of common pathogen biofilms by hindering biosynthesis (including E. coli, S. aureus, MRSA and P. aeruginosa), which avoided recurrent bacterial invasion. Transcriptomics results demonstrate that the patch exhibits various bioactivities to promote proliferation, migration and vascularization, in contrast with traditional antibiotic therapy. In vivo infection model verification further demonstrates that this patch effectively clears biofilms to prevent the recurrent invasion of P. aeruginosa, while achieving substantial tissue regeneration through collagen deposition and neovascularization. This strategy provides a simple and efficient approach for persistent anti-infection application.

Materials with strong negative thermal expansion (NTE) are crucial for both fundamental research and thermal expansion control engineering. Our previous studies have shown that significantly enhanced NTE can be achieved in PbTiO₃-BiFeO₃ and PbTiO₃-BiCoO₃ ferroelectrics by improving the tetragonal distortion (c/a) of the parent PbTiO₃. However, the detailed microscopic mechanisms behind this intriguing phenomenon remain unclear. In this study, we explored the temperature-dependent chemical bonding characteristics using high-energy synchrotron X-ray powder diffraction combined with Rietveld refinement, the maximum entropy method, and first-principles calculations. The temperature evolution of the electron density distribution in the ferroelectric phase of 0.5PbTiO₃-0.5BiFeO₃ and 0.6PbTiO₃-0.4BiCoO₃ provides direct evidence of strong covalency, not only in the A-site Pb/Bi-O2 bonds but also in the B-site Ti/Fe/Co-O1 bonds. This covalent character promotes spontaneous polarization through displacements of the highly polarizable A- and B-site cations. Our results reveal that the distinct covalent nature of the Fe-O and Co-O bonds results in contrasting temperature-dependent unit cell volume behaviors, with PbTiO₃-BiFeO₃ exhibiting strong nonlinear NTE and PbTiO₃-BiCoO₃ displaying colossal volume contraction. These findings elucidate the microscopic origin of the NTE in PbTiO₃-based ferroelectrics and pave the way for the design of new materials with enhanced NTE properties.

Advancements in wearable human-machine interfaces require haptic systems that are mechanically compliant, functionally versatile, and capable of delivering rich tactile and proprioceptive feedback under varying interaction conditions. However, existing haptic devices are often constrained by bulky structures, rigid components, insufficient actuation modalities, and the absence of self-sensing capabilities, which restrict their wearability, responsiveness, robustness, and seamless integration with the human body. This work presents multimodal, self-sensing, haptic interfaces enabled by programmable soft magnetic composites and phase change materials, which provide three distinct working modes (normal, rotational shear, and skin stretch) within a compact, skin-conformal form factor. The haptic interface leverages soft magnets with programmable magnetization profiles to enable multimodal actuation. Hybrid electromagnetic coils, incorporating both solenoid and planar configurations fabricated with stretchable gallium-based conductors, are designed to enhance stretchability and actuation output. Combined with a Kirigami-patterned elastomeric spring, the haptic actuator generates forces and displacements that exceed human tactile perception thresholds while maintaining performance under deformation. Furthermore, the inductance-based self-sensing mechanism provides real-time displacement monitoring for closed-loop control, ensuring consistent performance across varying actuation and interaction conditions. Ultimately, our soft multimodal haptic device can facilitate selective stimulation of multiple cutaneous mechanoreceptors and has been demonstrated to accurately encode both limb spatial position and joint motion for comprehensive proprioceptive feedback.

Conventional Miura Origami (Miura-Ori) metamaterials, despite their geometric elegance and tunable folding behavior, are inherently constrained in energy absorption performance due to their rigid periodicity and structural uniformity. In this work, we disrupt these limitations by introducing strategically engineered geometric disorder into Miura-Ori-based sandwich structures, resulting in dramatic enhancements in both mechanical robustness and energy dissipation. Among the tested designs, the best-performing disordered structures exhibit a 194.98% increase in elastic modulus, 105.22% enhancement in specific energy absorption, and 118.03% rise in mean compressive force compared to their uniform counterparts. Driven by these breakthroughs, we develop a powerful computational inverse design algorithm that autonomously generates geometric configurations to precisely match target force-displacement profiles. This algorithm unlocks a vastly expanded design space, enabling the creation of highly customizable and high-performance disordered metamaterials. Rigorous simulations and experimental validations corroborate the superior capabilities of our approach. As a compelling application, we design a Miura-Ori-inspired fuselage tube, where geometric disorder effectively suppresses peak impact forces during crash events. This study redefines the role of disorder-transforming it from a structural limitation into a functional asset-and establishes a foundational paradigm for the data-driven design of next-generation energy-absorbing metamaterials.

Daytime sub-ambient radiative cooling offers a passive means of reducing surface temperatures below ambient levels under direct sunlight. Existing hybrid systems that combine radiative and evaporative cooling rely exclusively on broadband radiative coolers, which are effective only for sky-facing horizontal surfaces. However, their performance deteriorates sharply in vertical orientations, such as building façades and vehicle exteriors, where angular limitations and environmental heat gains significantly diminish cooling efficiency. Here, we present a robust approach that achieves persistent sub-ambient daytime cooling on vertical surfaces by integrating a spectrally selective thermal emitter with a self-hygroscopic hydrogel. The selective emitter minimizes radiative heat influx from the ground and surroundings while protecting the hydrogel, which absorbs atmospheric moisture at night and drives evaporative cooling during the day. Under direct solar irradiation of 900 W m^-2, our system achieves temperature reductions of up to 6.1 °C below ambient temperatures. This durable and orientation-tolerant cooling strategy provides a practical pathway to extend passive cooling technologies from horizontal to vertical and other non-traditional surfaces.

Seawater splitting has emerged as a promising alternative to overall water splitting because it eliminates the kinetically sluggish oxygen evolution reaction (OER), which is a bottleneck in water splitting, and avoids the low economic value of O₂. Moreover, in seawater splitting, H₂ evolution coupled with the oxidation of chloride (Cl^-) to value-added chlorine (Cl₂) and/or hypochlorous acid (HOCl) can simultaneously benefit the energy and environmental sectors. Cl₂ and HOCl are widely used for bleaching, disinfection, sanitisation and sterilisation in the medical sector and for purifying drinking water and water in swimming pools owing to their strong oxidising and antibacterial properties. Mainstream industrial production employs the chlor-alkali electrolysis of sodium chloride (NaCl), which requires significant energy input and releases enormous amounts of CO₂. To achieve the sustainable production of Cl₂ and HOCl while reducing energy consumption and environmental impacts, photocatalytic (PC) and photoelectrochemical (PEC) technologies have been employed as green alternatives. Importantly, PC and PEC enable the on-site production of Cl₂/HOCl in remote areas, which can circumvent their instability (decomposition), storage and transport issues. This article reviews the recent progress in the PC and PEC production of Cl₂/HOCl, along with the catalytic materials used and their designs and photocatalytic performance. The applications of in situ HOCl production in anti-bacterial treatment, ammonia removal, the selective oxidation and conversion of organic compounds, and CO₂ conversion are discussed. We also address the challenges in this area and highlight prospects for future research directions. Overall, we demonstrate that the PC and PEC production of Cl₂/HOCl serves as a green and sustainable alternative to the chlor-alkali process. This research area is still in its infancy, and we hope that this review article will garner the attention of researchers to contribute to this area, leading to a step closer toward practical applications.

Freshwater harvesting is an important strategy to address water scarcity and provide a sustainable solution to such global challenges. In recent years, nanostructure-doped polymer hydrogels (NSPHs) have gained popularity as advanced materials with promising capabilities for effectively enhancing fog-harvesting performance due to their desirable structural, thermal, and surface features. Fog harvesting is an important technique for freshwater collection. This review discusses the progress in fog harvesting; including material innovations, structural design, mechanistic understanding, hydrogel principles, challenges, and advancements in NSPHs.The aim of this study is to provide a comprehensive framework for novel applications in promising research areas, establishing nanoparticle-doped polymer hydrogels as next-generation sustainable fog-harvesting materials. Nanoparticles enhance surface wettability, nucleation sites, surface-to-volume ratios, flexibility, thermal conductivity, solar absorption, and directional water transport, enabling the application of these composites in sustainable agricultural practices, renewable energy production, and smart water management. The study concludes by identifying key research gaps in advanced material performance, scalability, and sustainability on a local scale; intelligent hydrogel-based nanocomposite systems will ultimately address the implications of global water scarcity through fog harvesting.