Materials Horizons最新文献

To further meet the application needs of lithium-ion batteries, developing cathodes with higher voltage and higher operating temperatures has become a primary goal. However, LiCoO₂ cathodes encounter structural issues, particle fracture, and side reactions during high-voltage and high-temperature cycling. Thus, this work designs a novel interface engineering approach involving near-surface Li layer regulation and enhances the stability of the R3̄m layered structure, suppressing intergranular cracking. An undistorted surface with reduced phase transitions was revealed by the HAADF-STEM. The interface regulation by post-cycle simulations and XRD stabilizes interplanar spacing. The strong B-O bonds lower the O 2p energies, preventing oxygen loss and side reactions confirmed by XPS and band structure. Therefore, even under 50 °C, the half-cell maintains a capacity retention rate of 79% after 200 cycles at 5C at 4.5 V.

Developing low-cost and high-efficiency electrocatalysts is the key to making energy-related electrocatalytic technologies commercially feasible. In recent years, nickel phosphide (Ni_xP_y) electrocatalysts have received extensive attention due to their multiple active sites, adjustable structure and composition, and unique physicochemical properties. In this review, the latest progress of Ni_xP_y in the field of electrocatalysis is reviewed from the aspects of the properties of Ni_xP_y, different synthesis methods, and ingenious modulation strategies. The significant enhancement effects of elemental doping, vacancy defect, interfacial engineering, synergistic effect, and the external magnetic field excitation-enhanced strategy on the electrocatalytic performance of Ni_xP_y are emphasized, Moreover, a forward-looking outlook for its future development direction is provided. Finally, some basic problems and research directions of Ni_xP_y in high-efficiency energy electrocatalysis are presented.

The insufficient structure and interfacial stability of O3-type layered oxide cathode materials hinder their practical application in sodium-ion batteries, particularly at high temperatures. In this study, a thin, island-like NaTi₂(PO₄)₃ coating layer (∼15 nm) is constructed on the surface of NaNi_1/3Fe_1/3Mn_1/3O₂ through an in situ reaction involving nano-TiO₂, Na₂CO₃ and NH₄H₂PO₄. During the high-temperature calcination process, partial Ti-atom diffusion into the NaNi_1/3Fe_1/3Mn_1/3O₂ lattice results in the expansion of the interslab of the sodium layer and a reduction in lattice oxygen vacancies. Benefitting from the stable NaTi₂(PO₄)₃-modified interface and enhanced structural stability, the NaNi_1/3Fe_1/3Mn_1/3O₂ coated with 2 wt% NaTi₂(PO₄)₃ exhibits optimal cycle stability at high temperature. It retains 90.3% of its initial capacity after 100 cycles at 0.5C (1C = 130 mA g^-1, 45 °C). This dual-modification strategy, obtained from a facile approach, has the potential to facilitate the practical application of O3-type layered oxide cathode materials.

Thermochromic hydrogel is a versatile smart material that can be used in various applications. In this paper, we present a new concept of smart windows to passively regulate light transmittance and reduce energy consumption while functioning as an information display. By incorporating passive solar regulation and active local control, this window is devised through the multilayer assembly of tailored poly(N-isopropylacrylamide) (PNIPAM) hydrogels and surface-modified photonic crystal films. The modified surface tension of solvent tunes the scattering center size of the hydrogel, and the addition of the photothermal films (PT films) imparts a high near-infrared (NIR) shielding and light-to-heat conversion, which is needed for low-latitude smart window application. Together with high writing speed, clarity, and repeatability for local writing. This new smart hydrogel engineering can have broad applications, allowing more functionalities in designing building façades.

Spiking neural networks (SNNs) represent a promising frontier in artificial intelligence (AI), offering event-driven, energy-efficient computation that mimics rich neural dynamics in the brain. However, running large-scale SNNs on mainstream computing hardware faces significant challenges to efficiently emulate these dynamical processes using synchronized and logical chips. Memristor based systems have recently demonstrated great potential for AI acceleration, sparking speculations and explorations of using these emerging devices for SNN tasks. This paper reviews the promises and challenges of memristive devices in SNN implementations, and our discussions are focused on the scaling and integration of neuronal and synaptic devices. We survey recent progress in device and circuit development, discuss possible pathways for chip-level integration, and finally probe into hardware-oriented algorithm designs. This review offers a system-level perspective on implementing scalable memristor based SNN platforms.

Aiming to increase the dielectric breakdown field strength (E_bf) of yttria films for application in semiconductor manufacturing, a synthetic strategy based on photo-assisted chemical solution deposition was developed to prepare yttria films with aggregates of very small nanocrystallites. Despite containing many elliptical pores, the films exhibited an E_bf exceeding 12.7 MV cm^-1, much higher than that predicted according to conventional experimental scaling laws. The combination of nanocrystallite agglomerates and elliptical pores, generally seen as defects, provides a new strategy for increasing the E_bf.

The topological domains in ferroelectrics have garnered significant attention for their potential applications in nanoelectronics. However, current research is predominantly limited to rhombohedral BiFeO₃ materials. To validate the universality of topological domains in non-rhombohedral ferroelectrics, it is crucial to explore the existence and characteristics of topological states in alternative material systems. In this work we successfully construct topological polar structures in PbTiO₃ nano-islands with a tetragonal structure. Furthermore, the topological structures can be well manipulated by electric field and mechanical stress, making them switchable between center-divergent structure and center-converging types. Phase-field simulations revealed that the aggregation and redistribution of free charges play a decisive role in the formation and manipulation of topological states. These findings not only verify the feasibility of constructing topological domains in universal ferroelectrics, but also validate the multiple manipulability of these topological domains, displaying their significant potential in high-density nonvolatile memory devices.

Efficient, green, and intrinsic solar-photothermal conversion elastomers are crucial for sustainable energy solutions. However, the traditional elastomer/solar-absorber composites suffer from poor compatibility, resulting in a low solar-photothermal efficiency and suboptimal mechanical properties. Herein, chitosan was selectively oxidized and blended with XNBR emulsion, followed by the incorporation of Fe₂(SO₄)₃ and CuSO₄ to create a dinuclear heterodentate coordination structure as a novel crosslinked network within the XNBR composites (XNBR/OCTS/Fe₂(SO₄)₃/CuSO₄). Remarkably, without sulfurization, the composite achieved a tensile strength of 12.7 MPa and an elongation at break of 955%. The carbonization of OCTS, along with the in situ reduction of Cu nanoparticles through interface reactions facilitated the XNBR/OCTS/Fe₂(SO₄)₃/CuSO₄ composite to possess a significantly enhanced intrinsic solar-photothermal conversion efficiency. Under 1 min infrared irradiation with 100% elongation, the localized temperature of the composite increased from 27 °C to 137 °C. For the first time, carbonized OCTS was utilized to significantly improve the photothermal conversion, deviating from its traditional role as a polysaccharide-based substrate. Additionally, XNBR/OCTS/Fe₂(SO₄)₃/CuSO₄ exhibited strong antibacterial activity against E. coli and S. aureus, and the XNBR matrix could be recovered through acidolysis of the OCTS owing to the dissociation of the dinuclear heterodentate coordination network. This approach provides a valuable framework for designing high-performance intrinsic solar-photothermal conversion elastomers using sustainable green resources.

With the continuous advancement of electronic technology, there is an increasing demand for high-speed, high-frequency, and high-power devices. Due to the inherently small thickness and absence of dangling bonds of two-dimensional (2D) materials, heterojunction bipolar transistors (HBTs) based on 2D layered materials (2DLMs) have attracted significant attention. However, the low current density and limited structural design flexibility of 2DLM-based HBT devices currently hinder their applications. In this work, we present a novel vertical GaN/WSe₂/MoS₂ HBT with three-dimensional (3D)-GaN/2D-WSe₂ as the emitter junction. Harnessing the high carrier concentration and wide bandgap of 3D-GaN, an HBT with a current density of about 260 A cm^-2 is obtained. In addition, by selecting an adequate position for the collector electrode, we achieve efficient carrier collection through a collector junction smaller than the emitter junction area, obtaining a common-base current gain of 0.996 and a remarkable common-emitter current gain (β) of 12.4.

Photothermal agents (PTAs) have received significant attention in medical therapeutic and diagnostic applications. Despite their tremendous development, developing PTAs is challenging when applied to a living body with deep tissue, as it usually leads to attenuated therapeutic efficiency and potential biosafety hazards. Here, we report a molecular isomerization strategy based on NIR-II semiconducting biradicals that boosts the performance of NIR-II phototheranostics. With a stereoisomeric design by precisely manipulating the substitution position of the alkyl side chain, the optimal isomer, α-TBTS, and its nanoparticles (NPs) provide enhanced NIR-II absorption and 63% photothermal conversion capabilities, resulting in efficient photoablation of tumor cells. Most importantly, the relationship between the molecular isomerism of these NIR-II theranostics enables enhanced NIR-II performance, which has been proven by theoretical and ultrafast spectroscopy studies. With all these advantages, the α-TBTS nanoplatform has simultaneously achieved high-resolution whole-body NIR-II angiography and trimodal tumor-targeted imaging in vivo. Moreover, α-TBTS NPs efficiently inhibited tumor growth without recurrence upon NIR-II light irradiation, providing good biosafety. This work demonstrates the feasibility of molecular isomerization in multimodal NIR-II biradical PTAs and thus provides a suitable theranostic agent for high-performance tumor phototheranostics.