In the past decade, plasmonic metal heterostructures have been widely studied for their unique plasmon-enhanced effects and synergistic effects between different constituents. The intriguing properties of plasmonic metal heterostructures arise from the synergistic and/or complementary interactions of their components and the nanoscale interfaces between different materials. In addition, plasmonic metal heterostructures exhibit interesting optical and catalytic properties depending on their composition, shape, size, and architecture. This review provides an overview of the recent progress on the synthesis of plasmonic metal heterostructures including core-shell, core-satellites, Janus, and other typical structures, and then introduces some of the latest applications including surface-enhanced Raman scattering, sensing, and electrocatalysis of these plasmonic metal heterostructures. Finally, the challenges and prospects for the development of novel high-performance plasmonic metal heterostructures in the future are presented.

Solid-state batteries show high safety and theoretical energy density, receiving rapidly growing attention in both academic investigations and industrial applications. The garnet-type-based solid electrolytes (Garnet-SEs) play a vital role due to their high Li⁺ conductivity and electrochemical stability. The atomic structure at local environments, such as the Li⁺ coordination and site of doped ions, will have an important impact on the ability of transport and migration pathways that determine ion conductivity and electrochemical performances. In addition to the average structure from long-range perspective, the understanding at atomic level will be crucial for developing strategies to enhance ionic conductivity in Garnet-SEs. Solid-state NMR is a powerful tool that can probe the local atomic environments and dynamics on a molecular level. NMR is proven as a suitable technique for characterizing the light weight and small radius of Li elements, which is challenging for some conventional methods. In this review, atomic structure, ion pathways, and dynamic and microstructure formation of Garnet-SEs from the NMR view were discussed. These insights obtained from various NMR techniques will provide essential information for informing the control development and optimization of Garnet-SEs, contributing to the advancement of high-performance, safe, and reliable solid-state batteries.

Metastable perovskite oxides, with their complex atomic arrangements and nonequilibrium electronic structures, show great potential in fields such as energy conversion, storage, advanced optoelectronics, and intelligent sensing. Compared to conventional perovskites, metastable structures exhibit unique local symmetry breaking and oxygen vacancy modulation, high defect concentrations and tunable electronic structures. These features provide significant advantages in enhancing interfacial catalytic activity, ion transport, and photoelectric performance. However, their nonequilibrium structures tend to transform into more thermodynamically stable phases under typical synthesis conditions, complicating the study of their structure-property relationships and synthesis. This review adopts a structural materials perspective to analyze the unique advantages and structure-performance correlations of metastable perovskite oxides. Key concepts are introduced, categorizing these oxides based on their structural characteristics into four groups: symmetry-distorted type, Heterojunction type, Layered type, and Multivalent-regulated type, focusing on their impact on physicochemical properties. Major synthesis strategies, such as solid-state synthesis, high-pressure synthesis, pulsed laser deposition, salt-assisted method, and wet chemical approach, are systematically reviewed, highlighting their effectiveness in stabilizing metastable phases. The review also summarizes recent advancements in metastable perovskites, encompassing their types, structural features, synthesis methods, and applications, while identifying key challenges and future prospects in energy and information technologies.

Significant progress has been made in studying the microscopic mechanism of ferroelectricity in HfO₂ thin films. However, there is still insufficient research on the atomic arrangement and underlying principles of domain and phase boundaries. The atomic structure near the interface boundary can provide insights into the formation principles of phase boundaries, enabling a better understanding of phase stability, domain switching, and phase transformation. In this study, the aberration-corrected scanning transmission electron microscope is used to investigate the atomic structure of HfO₂ materials at the boundaries. The study reveals the formation of orthorhombic phase (O phase)/monoclinic phase (M phase) interfaces throughout the entire grain, with both coherent interface and incoherent interfaces. By examining the atomic structure at these boundaries, we explain the strain and the structure of atoms at different phase boundaries. In a coherent interface, 90° charged domain walls and 90° uncharged domain walls are found, where charged domain walls have positively charged (oxygen-ion diminishing) and negatively charged (oxygen-ion accumulating) interfaces due to the polarization change in the direction perpendicular to the domain walls. In addition, the O phase/M phase coherent interface possesses a transition region between the O phase and M phase, but there is a stepped phase boundary structure in the O phase/M phase incoherent interface due to the high mismatch stress. These studies provide favorable assistance for the microstructure of phase stability and the evolution laws of phase transitions.

Employing organic semiconductors to drive photocatalytic processes for chemical fuel production and pollutant degradation is a viable pathway for tackling the energy crisis and environmental pollution. In this review, we summarize the development of organic semiconductor photocatalysis so far and propose the future vision of organic semiconductors as state-of-the-art photocatalysts in practical applications. Compared to inorganic semiconductors, organic semiconductors display a large absorption coefficient and easily tunable topological and electronic structures, which set them apart from ordinary inorganic photocatalysts. However, the chemical instability, high exciton dissociation energy and low charge carrier mobility of organic semiconductors are the major obstacles to the improvement of their photocatalytic activity. Obviously, the opportunity and challenge coexist in the development of organic semiconductor photocatalysis. In light of this, we systematically compare the merits and shortcomings of organic semiconductors for heterogeneous photocatalysis and enumerate some feasible approaches to overcoming the bottlenecks hindering their photocatalytic performance. By carefully considering factors such as conjugated linkage types, building blocks, and electron donor-acceptor structures, highly reactive and stable organic semiconductor photocatalysts can be developed.

Realizing nonvolatile multiple polarization states in ferroelectric-based memories holds great promise for high-density data storage and advanced nanoelectronics. In this study, through phase-field simulations, we proposed a novel nonvolatile multistate memory design using BiFeO₃ (BFO)-dielectric nanocomposites to enhance storage density. By embedding BFO pillars within a dielectric matrix, we stabilized four distinct polarization states. The effects of pillar sizes and electric fields on the stability and switching behavior of these states were systematically investigated, showing that all four states can be effectively switched using either uniform electric fields or localized voltages via a piezoresponse force microscope tip. Simulations of a 4 × 4 memory cell array further highlighted the potential of this design, achieving a storage density far exceeding that of conventional ferroelectric random access memory devices. Our work shows the potential of ferroelectric-dielectric nanocomposites on high-density, rapid-switching nonvolatile memory technologies.

TiO₂ is a well-known photocatalyst due to its excellent photocatalytic activity, low cost, and stability. However, its practical applications are limited by its poor charge transport and wide bandgap. In this study, F-doped TiO₂ nanorod arrays were synthesized using a simple chemical bath annealing method, which resulted in significantly improved properties. Among the samples, 0.05F-T (F-doped TiO₂ nanorods) exhibited the best performance, with a photocurrent of 7.34 mA/cm² at 1.8 V vs. reversible hydrogen electrode (RHE), which is 4.61 times higher than that of pure TiO₂ nanorods (1.59 mA/cm²). Incident photon-to-current efficiency measurements showed prominent photocurrent responses in the 325-375 nm range and a slight redshift toward the visible region around 425 nm, indicating improved light absorption. The electron-hole separation efficiency was enhanced, and bandgap and flat-band potential measurements confirmed the optimization of the energy band structure. The photoelectrochemical performance for water splitting was also evaluated, with 0.05F-T achieving the highest hydrogen production of 842.28 µmol/cm² in 5 h at 1.8 V vs. RHE, which is 6.58 times higher than that of pure TiO₂ (128.05 µmol/cm²). These results demonstrate that F-doped TiO₂ nanorods are promising for enhancing photocatalytic hydrogen production.

Highlights

1. A simple wet chemical soaking method introduces the Fluoride (F) element into the TiO₂ lattice.

2. F element doping changes the lattice spacing of TiO₂ and optimizes the band structure.

3. The doping of the F element causes a red shift in the wavelength of TiO₂ light absorption.

4. Efficient photoelectrochemical water splitting achieved by F-doped TiO₂ nanorods.

The bulk photovoltaic effect of perovskite ferroelectric oxides has been widely explored because of its ability to obtain the above-bandgap photovoltage. However, the photovoltaic current in these materials remains low at the nA level in the visible-light range, severely limiting the device applications due to a wide bandgap. Herein, we report a Ni ions-assisted coprecipitation-hydrothermal method to regulate the growth of single-crystal PbTiO₃ film with a controlled thickness from 0.7 μm to 2.2 μm. The epitaxial relationship between the tetragonal perovskite film and cubic Nb:SrTiO₃ substrate has been characterized to be {001}_film || {100}_substrate. The film adopts a single-domain structure with a polarization direction pointing to the substrate. Interestingly, the film exhibits a large photovoltaic current under 405 nm irradiation, with values reaching 3.6 mA/cm², which is ∼ 3.6 times higher than those of the reported ferroelectric materials. Introducing Ni ions as an additive into the precursor solution was investigated to effectively mediate the competitive nucleation and growth processes between the film and the by-product powder, thereby enabling a tunable thickness of the films. An intriguing Ti-vacancy composition gradient was revealed throughout the film and its coupling with the spontaneous polarization generates a polarization gradient and thus a built-in electric field, accounting for the excellent photovoltaic performance reported here.

Photocatalytic hydrogen production is a sustainable approach to addressing energy and environmental issues, with ZnS being a prominent photocatalyst due to its efficiency, stability, and affordability. However, its wide bandgap and quick carrier recombination hinder its performance. Non-metal doping, particularly with nitrogen and carbon, has been shown to enhance electronic structure, light absorption, and charge separation of ZnS, thus improving its photocatalytic activity. This review highlights the advancements in nitrogen-doped, carbon-doped, and carbon-nitrogen co-doped ZnS, emphasizing nitrogen's significant impact on bandgap reduction and charge transfer, and carbon's role in promoting heterojunctions and active sites. Co-doping further amplifies these effects, leading to superior photocatalytic performance. The review also discusses performance variations among catalysts, the effects of synthesis methods and reaction conditions, and the role of auxiliary agents. Future research should concentrate on comparing doping methods, optimizing synthesis, and exploring phase-dependent activities to maximize the potential of ZnS-based photocatalysts. This work highlights the benefits of non-metal doped ZnS in hydrogen production and outlines key challenges and future research directions in the field.

Lattice softening refers to reducing the lattice stiffness of materials by weakening the binding force between atoms, thereby changing the electron and phonon transport characteristics. The advantage of lattice softening compared to other strategies for optimizing the properties of thermoelectric materials is that it can significantly reduce the lattice thermal conductivity by reducing the sound velocity without significantly affecting the electrical properties. Moreover, lattice softening shows a wide range of application potential in other material fields, such as magnetostrictive materials and intermetallic alloys. However, systematic reviews on the causes, effects, and specific applications of lattice softening in thermoelectric materials are still limited. This review introduces the recent progress of lattice softening in thermoelectric materials, focusing on how to achieve it and its mechanism in optimizing thermoelectric performance. Through mechanical strain engineering, chemical doping, and phase transition strategies to achieve lattice softening, one could lower the phonon speed, reduce the lattice thermal conductivity, and optimize the Seebeck coefficient and conductivity. In the outlook section, the potential applications of lattice softening in sustainable energy technologies are explored.

The lung, a vital organ for homeostasis, is vulnerable to various diseases that challenge healthcare systems due to limited treatment options. Fortunately, mRNA-based gene therapy offers a promising solution, demonstrating high efficiency and safety across applications in vaccines, protein replacement therapy, and cancer treatment. However, naked mRNA faces challenges like degradation, poor cell penetration, and immunogenicity. The lung’s complex structure further complicates mRNA delivery. In this way, lipid nanoparticles (LNPs) have emerged as an effective solution, demonstrated by their success in COVID-19 mRNA vaccines through superior encapsulation and biocompatibility. Extensive studies focus on developing LNP-based pulmonary mRNA delivery systems for treating viral infections and lung diseases.This review analyzes the current state and developments in mRNA-LNP applications for pulmonary diseases and LNP-based strategies for lung-targeted mRNA delivery. We explore the optimization and development of LNP platforms across four administration routes: nebulized inhalation, intratracheal administration, nasal administration, and systemic administration. Our goal is to provide researchers with a comprehensive reference covering both fundamental principles and cutting-edge developments in pulmonary mRNA-LNP delivery systems.

The development of oxygen reduction reaction (ORR) catalysts with high activity, stability, and economic applicability plays a decisive role in reducing expenses and enhancing the discharge performance of seawater-based zinc-air batteries (SWZABs). Co- and Fe-based single-atom catalysts (M-N₄-C) with metal-N₄ structure offer advantages of well-defined active structure and high active site utilizations. However, the oxygen electrocatalytic performance of M-N₄-C remains a formidable challenge due to the highly stable centrosymmetric electronic structure. To overcome the dilemma, we develop a Co-N₄Cl-C with axial coordination of Cl atoms. The axial coordination drags the Co atoms out of the Co-N₄ centrosymmetric configuration. This alters the electronic configuration of Co single-atom sites, resulting in a valence state change from +1.83 to +0.67 and forming a localized negative charge environment. These alternations enhance the electronic orbital overlap between Co single-atom sites and oxygen species, promote the rapid evolution of *OOH intermediates, and inhibit the adsorption of toxic Cl^- ions, ensuring the ORR kinetics and stability. Co-N₄Cl-C exhibits a high oxygen reduction onset potential of 1.05 mV and a half-wave potential of 0.88 mV vs. the reversible hydrogen electrode. The SWZAB, featuring a Co-N₄Cl-C catalyst cathode, Zn anode, and NaCl electrolyte supplemented with KOH, reaches a discharge voltage platform of 1.27 V and a peak power density of 179 mW·cm^-2, even at a current density of 10 mA·cm^-2. This study sheds important light on advancing single-atom catalysts with superior ORR performance and economic viability.

Zinc-iodine batteries (ZIBs) are considered a promising energy storage system, but are still plagued by low energy density and rampant side reactions originating from active H₂O molecules in the liquid electrolyte. Realizing the coupled redox reactions within I^-/I₀/I⁺ species, i.e., four-electron transfer reactions, is deemed an effective strategy for boosting the energy density of ZIBs, which is mainly blocked by the rapid hydrolysis of nucleophilic I⁺ ions. To address these issues, urea with diamine ligand sites (-NH₂) was introduced into the liquid electrolyte [urea electrolyte (UE)] to achieve durable four-electron ZIBs. As demonstrated by the spectroscopic characterization results, -NH₂ groups can bundle the active H₂O molecules by reconfiguring the hydrogen bonds, and provide additional electrophilic ligand sites for I⁺ ions. Based on these advantages, both the side reactions on the Zn anode and the I⁺ hydrolysis reaction on the I₂@AC cathode are remarkably mitigated, and four-electron transfer is realized at low zinc salt concentrations. As a result, the optimized UE electrolyte effectively stabilizes the zinc metal anode, and endows the I₂@AC cathode with a high reversible capacity of 187.2 mAh g^-1 after 250 cycles at 1 A g^-1. The disclosed intermolecular force modulation strategy in this work will offer a comprehensive perspective for the future design of liquid electrolytes for high-energy-density ZIBs.

The demand for single-photon high-sensitivity ultraviolet (UV) detection is continuously increasing in cutting-edge fields such as UV astronomy, environmental monitoring, and space communications. In particular, gallium nitride (GaN) is an ideal material for UV detection due to its wide bandgap (3.4 eV), strong radiation immunity, and visible/solar-blind properties. In this respect, avalanche photodetectors (APDs) are very promising candidates for single-photon UV detection due to their high sensitivity, large gain, high detection efficiency, and room temperature operation. This review summarizes the GaN avalanche breakdown characteristics, including current surge, positive temperature coefficient of V_br, and non-linear characterization. In addition, recent advances in various structural types of GaN APDs, such as p-i-n, separated absorption multiplication, optimized edge termination, and polarization-enhanced structures, are presented. In addition, the directions and challenges for the future development of GaN APDs are discussed. Although GaN-based APDs have significantly improved their UV single-photon detection performance through structural innovations, noise control, linearity optimization, and process simplification remain the core challenges. In the future, the integration with two-dimensional material heterojunction and new light trapping structure is expected to break through the existing bottleneck and promote its application in frontier fields such as deep space exploration and quantum communication.

MXenes, a class of two-dimensional transition metal carbides and nitrides, have garnered significant attention for their unique properties, making them promising candidates for next-generation energy harvesting technologies. Among these, emerging MXene-based hydrovoltaic electricity generators (HEGs), including moisture electricity generators, evaporation electricity generators, reverse electrodialysis electricity generators, and droplet electricity generators, have demonstrated exceptional performance in converting energy in environmental water such as moisture, water, wave, and droplets into electricity. Additionally, the synergistic coupling of MXene HEGs with other energy harvesting systems, such as triboelectric nanogenerators and thermoelectric generators, offers new avenues for enhancing power generation performance and expanding application scenarios. This review systematically examines the structures and properties of MXenes, their application in various HEGs, and the recent advancements in their integration with other energy harvesting systems. Furthermore, we discuss the challenges and future opportunities for MXene-based devices in multifunctional energy harvesting platforms.

Photothermoelectric (PTE) detectors hold immense potential for converting incident light signals into electrical signals, finding applications in sensing, astronomy, night vision, and communication. However, their widespread adoption is hindered by issues such as slow response times, low responsivity, and poor stability. In this study, a high-performance self-powered PTE detector based on the Ag₂Se nanorods (NRs) and multi-walled carbon nanotubes (MWCNTs) is reported for the first time. The findings reveal that the electrical conductivity of the film increases with the addition of MWCNTs, albeit at the expense of the Seebeck coefficient. Notably, the film containing 0.5 wt% MWCNTs exhibited a superior power factor (303.22 μW·m^-1·K^-2) at 300 K. Owing to the high PTE performance, the photosensitive properties are characterized in an ultra-broadband range from the violet (405 nm) to infrared (2,500 nm) wavelengths, featuring rapid response time (1.4 s) and substantial output voltage (6.83 mV). Furthermore, the device demonstrated remarkable stability, with only a 3.4% decrease in output voltage after three months of air exposure and negligible changes in thirty cycles. Thus, the proposed device presents a novel strategy for developing PTE detectors characterized by broadband coverage, fast response times, and exceptional stability.

Photonic crystals (PCs) and metamaterials are periodic artificial structures with different scales that modulate light–matter interactions. Considering their complementary advantages, the concept of photonic meta-crystals is proposed. In these hybrid structures, such as hypercrystals (composed of hyperbolic metamaterials and PCs), the photonic band gap provided by PCs can be blue-shifted with more degrees of freedom, and the weak coupling of hyperbolic metamaterials to the environment can be enhanced. This review introduces photonic meta-crystals in sequence, based on the classification of electromagnetic parameters in metamaterials. Recent advances in photonic meta-crystals are also presented in the context of topological semimetals.

Hydrogen energy, characterized by its cleanliness, high energy density, and zero carbon dioxide emissions, is increasingly recognized as a promising alternative to traditional fossil fuels. From this perspective, the highly efficient generation of hydrogen is of paramount importance for mitigating the urgent global energy shortage and environmental challenges. In contrast to conventional fossil fuel-based hydrogen production methods, advanced catalytic technologies that generate hydrogen from water or other renewable resources offer environmentally friendly and sustainable alternatives. In this context, this review exclusively examines the fundamental principles of representative catalytic hydrogen production technologies, encompassing electrocatalytic, piezocatalytic, pyrocatalytic, photocatalytic, and their synergistic catalytic methods at first. Secondly, the latest advancements in the above-mentioned catalytic hydrogen evolution pathways are scrutinized from the perspectives of material composition, structure designs, and hydrogen generation yields. Finally, a comprehensive summary and future outlook for the advancement and practical applications of catalytic hydrogen production technologies are provided. This in-depth review aims to offer both theoretical insights and experimental guidance to researchers in the fields of catalysis, environmental science, energy research, and related areas.

Lithium-ion batteries have come to dominate the secondary energy storage market; however, their broader application is limited by the scarcity of lithium resources and high production costs. As a promising alternative, sodium-ion batteries (SIBs) have attracted significant attention due to their similar electrochemical behavior and the abundant availability of sodium-based raw materials. It is well recognized that the electrode material plays a crucial role as it directly influences the overall cycle life of the battery. Iron-based materials are particularly attractive due to their abundant raw material availability, cost-effectiveness, safety profile, and environmental friendliness; thus, they represent one of the most suitable classes of electrode materials. Recently, many studies have focused on designing appropriate nanostructures and developing straightforward methods for improving the electrochemical features of conversion-type iron-based electrodes. This review summarizes recent advancements in iron-based electrodes for SIBs and outlines future directions for the advancement of conversion-type iron-based materials. It is expected to provide valuable insights for the design of high-performance iron-based electrodes for SIBs.

Dielectric composites play a crucial role in meeting the growing demand for high-energy-density capacitors that can operate effectively in challenging environments. These applications include aerospace power management, underground oil and gas exploration, electrified transportation, and pulse power systems. This work provides a comprehensive overview of current research on flexible, high-temperature-resistant composite dielectrics for energy storage, emphasizing enhancing thermal stability and dielectric performance. Initially, this work examines the crucial characterization parameters that define the performance of dielectric energy storage materials at elevated temperatures and explores the mechanisms behind them. Subsequently, the recent research achievements and the primary challenges facing these flexible composite materials are summarized. Further discussions on strategies are performed for optimizing the microstructure of these materials to improve performance, where three key dimensions are analyzed, such as system selection, filler types, and structural design. Additionally, the review introduces innovative approaches to enhance the temperature resistance of flexible dielectric composites, employing machine learning algorithms and high entropy design concepts. Finally, a summary and future outlook on the potential development pathways in this field are concluded.

Textured ceramics exhibit a reduced coercive field, and when aligned in the same direction as the spontaneous polarization, they enhance the adiabatic temperature change (ΔT) of the material. In this paper, we employ a polycrystalline phase-field model to analyze the solid solution Ba_0.8Sr_0.2TiO₃ (BST80) with a <001> orientation, alongside randomly oriented polycrystals, aiming to investigate the influence of texturing on the electrocaloric effect (ECE) performance. We examine six distinct groups characterized by varying grain orientation angles for the randomly oriented polycrystals for hysteresis loop calculations. Utilizing Maxwell's relations, we compute the ECE for the randomly oriented BST80 polycrystal and the <001>-textured BST80 polycrystal across different electric field strengths. The findings indicate that the ΔT achieved with the <001>-textured BST80 polycrystal surpasses that of the randomly oriented BST80 polycrystal. Furthermore, the temperature at which the maximum ΔT occurs for the <001>-textured BST80 polycrystal is observed to be shifted to higher values compared to the randomly oriented variant. The observed enhancement of ECE in BST80 polycrystalline ceramics due to texturing offers valuable insights and foundational knowledge for future theoretical and experimental investigations.

In-situ neutron diffraction during the thermomechanical controlled processing was employed to investigate the effect of ausforming on isothermal transformation below the martensite start temperature (Ms) in the NiCrMoV steel. After the occurrence of athermal martensitic transformation during cooling of the austenitized sample, the isothermal transformation below the Ms proceeded in two distinct stages: Stage 1, characterized by a rapid transformation rate, and Stage 2, which progressed more slowly. Ausforming suppressed both the athermal martensitic transformation and isothermal transformation in Stage 1 through mechanical stabilization. In contrast, ausforming accelerated the isothermal transformation in Stage 2, likely due to the enhanced carbon diffusion, indicating bainitic transformation characteristics in this stage. The resulting microstructure consisting of tempered martensite, bainite and retained austenite exhibited an excellent strength-ductility balance, achieving an ultimate tensile strength of 1989 MPa, a uniform elongation of 7.1%, and a total elongation of 16%. The present study provides new insights into phase transformation mechanisms below Ms and demonstrates the potential of ausforming-assisted processing for enhancing the mechanical properties of high-strength steels.

The pursuit of unparalleled mechanical properties has driven the exploration of heterostructured materials in recent years. Traditional strategies that rely on tuning internal plastic strain to create heterogeneous distributions of martensite have failed to overcome the strength-ductility trade-off in materials, despite the desirable extensive hardening effect of martensitic transformation. Here, we report a paradigm-shifting approach utilizing dislocation-mediated heterogeneous martensitic transformation to resolve this dilemma. Realized in a partially recrystallized metastable face-centered cubic (FCC) high-entropy alloy (HEA), the phase transformation from FCC to a hexagonal close-packed (HCP) structure occurs exclusively in the non-recrystallized zones during initial tensile loading, facilitated by abundant pre-existing dislocations serving as sources for partial dislocations. In contrast, deformation in the adjacent recrystallized zones, which are devoid of dislocations, proceeds through dislocation slip. The resulting heterogeneous deformation persists with increasing strain, underpinned by the emergence of unique dual FCC-HCP nanograins at localized HCP lamellar intersections in the non-recrystallized zones. Such sustained heterogeneous deformation enables the full exploitation of remarkable hetero-deformation-induced strengthening and strain hardening, leading to a superior strength-ductility combination in the current HEA. Our findings establish a new pathway for engineering high-performance heterostructured materials.

Developing wrought aluminum-lithium alloys with high strength and ductility has been a longstanding objective in the aviation and aerospace industry. However, the conventional T8 thermo-mechanical treatment process faces challenges in overcoming the strength-ductility compromise in aluminum-lithium alloys. The precipitates-dislocation interaction is critical in governing the balance between strength and ductility. When the aging temperature exceeds 175 °C, the T₁ phase thickens, making it difficult for slip dislocations to shear the coarser T₁ phase. This results in severe matrix distortion near the precipitates, thereby reducing ductility. In contrast, aging at 150 °C promotes the formation of fine, shearable T₁ phases, facilitating uniform plastic deformation across multiple slip planes and achieving a balance of high strength (~ 705 MPa) and ductility (~ 11.8%). Aging at 120 °C further improves ductility (~ 12.4%) due to the coexistence of sparse T₁ phases and large amounts of Guinier-Preston (GP) zones, which promoted dislocation cross-slip. Our findings highlight the critical importance of precisely controlling the relative amount, size, and distribution of GP zones and T₁ precipitates to achieve superior mechanical performance in Al-Cu-Li-Mg-Ag alloys.

Pore structures, critical for catalyst mass transfer efficiency and active site accessibility, present a cross-scale complexity that challenges conventional characterization methods. This study integrated synchrotron multiscale CT, mercury intrusion porosimetry, and nitrogen adsorption to achieve a comprehensive, full-scale analysis of the pore network in Ni-Fe industrial catalysts, spanning 1.48 nm to 365 μm. Through 3D reconstruction, the study unveiled complex structural features, such as cavity structures and “ink-bottle” pores, which are hard to capture with traditional single techniques. Comparing results from the three methods clarified the limitations of conventional approaches in analyzing complex pore sizes. Based on the pore characteristics of Ni-Fe catalysts, this study proposes a hierarchical pore structure design to optimize mass transfer and enhance performance. The integration of multiple techniques achieved complementary advantages, and the in-depth analysis based on this multimodal approach provides quantitative guidance for catalyst optimization and preparation. The findings offer a theoretical basis for developing more efficient and stable industrial catalysts and advancing catalyst design toward a digital and rational approach.

Aqueous zinc-ion batteries (AZIBs), as one of the most promising energy storage devices, have attracted widespread attention owing to their abundant resources, environmental friendliness, and high safety. As a crucial component of AZIBs, the electrochemical performance of cathode materials plays a decisive role in battery performance, thus necessitating in-depth investigations into the structure and properties of cathode materials. Manganese dioxide (MnO₂), as a cathode material for AZIBs, has garnered significant interest owing to advantages such as the low cost of manganese, stable structure, simple synthesis process, and abundant raw materials. Additionally, it exhibits high specific capacity and tunable cycling performance. However, MnO₂ as a cathode in AZIBs is plagued by structural deformation, side reactions, and the Jahn-Teller effect during cycling. Therefore, it is essential to comprehensively review the research progress, reaction mechanisms, and optimization strategies of MnO₂ in AZIBs.

Herein, MnO₂ is taken as the research focus. Firstly, we comprehensively summarize the development status and research progress of MnO₂ materials as cathodes for AZIBs. Subsequently, we conduct an in-depth analysis of the structural evolution and Zn²⁺ storage mechanisms of MnO₂ during cycling, including the conversion reaction mechanism, Zn²⁺ intercalation mechanism, dissolution-deposition mechanism, and H⁺/Zn²⁺ co-intercalation mechanism. Building on this, various optimization strategies such as structural control, morphological regulation, defect engineering, and electrolyte development are systematically reviewed. Finally, we outline future research directions for high-performance MnO₂ cathodes, put forward a rational research roadmap to maximize the electrochemical properties of MnO₂, and facilitate the construction of stable AZIBs.

This review explores the intricate relationship between metal doping and the polarization-switching dynamics of wurtzite-phase aluminum nitride (AlN) thin films. We examine how the dopant type, concentration, and resulting crystal structure affect the ferroelectric characteristics of AlN. Particular emphasis is placed on scandium-doped AlN (AlScN), a leading candidate for next-generation ferroelectric applications. We investigate the fundamental mechanisms underlying polarization switching, emphasizing the roles of local chemical interactions, structural modifications, and domain wall dynamics. In addition, we present a comparative analysis of key synthesis techniques - including magnetron sputtering, molecular beam epitaxy, atomic layer deposition, and pulsed laser deposition - highlighting their respective advantages and limitations in fabricating high-quality ferroelectric films. By elucidating the core principles governing ferroelectricity in doped AlN, this review provides valuable insights for the design and optimization of advanced ferroelectric devices aimed at improving performance and energy efficiency.

TiAl alloys are considered promising candidates for high-temperature structural applications, primarily because of their low density and good high-temperature performance. However, their broader application remains restricted due to poor ductility and inadequate deformation compatibility. The (α₂+γ) lamellar structure, which dominates the service microstructure, exhibits strong deformation anisotropy. Moreover, the large plasticity difference between the α₂ and γ phases leads to pronounced inhomogeneous deformation. Accordingly, internal stress accumulates in the α₂ phase and may initiate cracks at the α₂/γ interfaces. The formation of deformation textures further influences the microscopic deformation and complicates the analysis of stress distribution. Understanding the underlying deformation mechanisms and stress evolution requires real-time observation of these dynamic processes. To this end, synchrotron X-ray diffraction and neutron diffraction are employed for their deep penetration capability and high spatial and temporal resolution. These advanced techniques enable in situ tracking of lattice strain evolution, load partitioning, and phase transformation. This review highlights the deformation behavior of TiAl alloys, including their elastic and plastic responses, texture evolution, and internal stress accumulation. Particular attention is given to the reversible stress-induced α₂→O phase transformation, which presents promising opportunities for enhancing mechanical performance through targeted microstructural optimization.

Cancers represent a complex and multifaceted health challenge, marked by elevated disease burden and fatality rates stemming from both genetic alterations and epigenetic modifications. Nanomedicine, as an emerging field in oncological investigation, optimizes the site-specific delivery of chemotherapeutic compounds through innovative engineering approaches. This technological advancement enables the development of revolutionary strategies for designing precision-targeted treatments that maximize safety and effectiveness. Podophyllotoxin (PPT), a potent aryltetralin-class cytotoxic agent isolated from Podophyllum plants, has become a focal point in anticancer pharmaceutical development. Early research efforts focused on direct PPT administration for tumor management, yet clinical implementation through conventional delivery methods has been constrained by multiple factors including pronounced toxicity profiles, limited aqueous solubility, and narrow therapeutic windows. Advances in nanotechnology and biomaterials effectively enhance PPT therapy's potential for cancer treatment in clinical settings. Various PPT-based nanomedicines have been explored in recent years (2022-2025), including carrier-free nanodrugs, liposomes, polymeric micelles, polymer-drug conjugates, host-guest drug delivery systems, and peptide-based nanoparticles, which utilize passive targeting, active targeting, and stimulus-responsive targeting mechanisms to improve tumor-directed drug delivery. Nevertheless, due to the complexity of the tumor microenvironment, single PPT nanomedicine has suboptimal therapeutic efficacy. PPT-based "combo" drug delivery system facilitates innovative multi-dimensional therapies - such as chemotherapy combined with photodynamic therapy, photothermal therapy, immunotherapy, and chemodynamic therapy - to deliver superior therapeutic benefits and jump the “valley of death”. This review explores delivery strategies of PPT-based nanomedicines and may spark new ideas for multimodal treatment protocols, providing an entry point for professionals to thrive in this exciting field.

Since the discovery of ferroelectricity in Si-doped HfO₂ in 2011, HfO₂-based materials have attracted extensive interest from researchers. Their various advantages provide a broad research prospect in the field of ferroelectric materials and devices. Researchers have conducted effective studies on the origin of ferroelectricity, the wake-up effect, the fatigue effect, and the potential for device applications. These studies contribute to a better understanding of the properties and applications of HfO₂-based materials. This article provides a comprehensive review of the origin and influencing factors of ferroelectricity in HfO₂, advantages in material applications, and limitations in applications from multiple perspectives. It also introduces the currently mature methods for preparing HfO₂-based ferroelectric materials and cutting-edge applications in different device fields. Finally, the future development prospects of HfO₂-based materials are also discussed.

The micromechanical behaviors and dislocation evolution in a polycrystalline Ni-Co-based superalloy were systematically investigated by in situ neutron diffraction tensile testing combined with line profile analysis. The results reveal the sequential activation of γ′ shearing and Orowan looping mechanisms, with interphase load partitioning governed by strain-dependent interactions of dislocation and precipitate. During the initial plastic deformation, the γ and γ′ phases undergo co-deformation through dislocation shearing without load transfer, while the Orowan looping facilitates the load transfer from γ to γ′ phase at a higher strain level. Furthermore, the low stacking fault energy leads to a rising fraction of screw dislocations by suppressing cross-slip. Crucially, the pinning effect of γ′ precipitates hinders the rearrangement of these dislocations into low-energy structures, resulting in the formation of high-energy, weakly screened dislocation configurations. These findings provide new evidence for the planar slip dominance in Ni-Co-based superalloys, enabling quantitative assessment of microstructural evolution and micromechanical responses.

Zero thermal expansion alloys possess significant potential for applications in aerospace, electronics, and optical instruments because their volume remains nearly constant despite temperature changes. Regulating and exploring zero thermal expansion alloys is crucial to mitigating thermal strain and stress. This study successfully adjusted negative thermal expansion alloy (Hf, Ta)Fe₂ to zero thermal expansion over a wide temperature range by optimizing its composition and controlling the magnetic phase transition. Moderately substituting Cr for Fe transformed the giant negative thermal expansion (ΔT = 15 K) into near-zero thermal expansion (ΔT = 200 K). High-resolution synchrotron X-ray diffraction, macroscopic magnetic measurements, and linear thermal expansion measurements were employed to investigate the crystalline structures, magnetic properties, and thermal expansion of Hf_0.84Ta_0.16Fe_2-xCr_x (0 ≤ x ≤ 0.25). The alignment of the magnetic phase transition and anomalous thermal expansion temperature ranges demonstrates the essential role of spin-lattice coupling. This work offers valuable insights into regulating zero thermal expansion behavior and explaining the applications of magnetic negative thermal expansion alloys. This advancement will promote their use in high-precision instruments, aerospace, microelectronics, and advanced manufacturing, enhancing device reliability and performance, particularly in extreme temperature environments.

Neutron imaging (NI) has emerged as a pivotal non-destructive characterization technique, leveraging its exceptional penetration through heavy metals and high sensitivity to light elements such as hydrogen and lithium. These unique properties render NI indispensable for the quantitative assessment of hydrogen in metallic materials, where hydrogen accumulation can significantly degrade mechanical performance. In this context, in-situ experimental setups capable of precise control over temperature, gas environment, and mechanical stress enable real-time monitoring of hydrogen absorption, diffusion, and spatial distribution. Recent advancements in NI have achieved hydrogen detection with concentrations as low as 5-10 wppm and spatial resolutions on the order of ~10 μm. To overcome challenges associated with ultra-low hydrogen quantification, such as the relatively low neutron flux, optimized imaging approaches, including the black body grid method, have been developed, enhancing measurement precision and enabling hydrogen concentration evolution to be resolved at the micrometer scale. This review highlights the latest developments in NI for hydrogen quantification, focusing on applications in structural metallic alloys and solid-state hydrogen storage materials, and discusses strategies to further improve spatial resolution, sensitivity, and experimental accuracy.

The formation and propagation of Lüders bands are important phenomena in the plastic deformation of some critical structural materials. The propagating Lüders front, which is structurally unstable, plays a key role in this process. Yet, the microstructural and stress states of the Lüders front are challenging to characterize and remain insufficiently understood. The present study utilized in-situ synchrotron-based high-energy X-ray diffraction on a fine-grained medium-Mn transformation-induced plasticity steel exhibiting typical Lüders banding behavior. Detailed analysis of evolving diffraction patterns was performed regarding peak intensity, full width at half maximum, and measured lattice strain. An abnormal measured lattice strain asymmetry was observed from the Debye rings that were collected when the Lüders front overlapped with the irradiated volume. This allows for a discussion of the local microstructural and stress states of the Lüders front, evidencing the possibility of a local shear stress component with a tilted principal stress axis. The work offers new insights into the micro-mechanisms of Lüders banding. It provides a practical and efficient analytical method for studying the dynamics of localized deformations, particularly when deformation is inhomogeneous within the characterized volume or inconsistent with macroscopic deformation.

Aberration-Corrected Scanning Transmission Electron Microscopy (AC-STEM) offers sub-ångström resolution and has become the most microscopic and advanced tool in the field of materials science, yet its quantitative image analysis has been constrained by high computational demands, uneven background illumination, and challenges in resolving overlapping point spread functions. In this work, we introduce STEMax_PF, a novel software tool that integrates and improves multiple advanced techniques - including an adaptive threshold-enhanced centroid method, rapid normalized cross-correlation for detecting light atoms, and an improved weighted overdetermined regression algorithm - to effectively address these issues. In the two-dimensional Gaussian fitting process, STEMax_PF adopts a unique strategy by individually estimating the initial fitting parameters for each atomic column using several approaches, ensuring accurate fitting for materials comprising any elements. The integration of these methods dramatically reduces computational resource usage and enables extremely fast processing. Furthermore, STEMax_PF is universally applicable to any crystal structure and STEM image format, paving the way for reliable quantitative atomic analysis and its connection to phenomena such as ferroelectric polarization, piezoelectric/dielectric responses, and electron-phonon interactions.