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The general mechanism of emittance variation is proposed using first-principles prediction in 76 kinds of phase-changing ABO3 perovskites, and the connections of emittance variation with bandgap difference and volume-distortion rate are described.

Despite the elaborate varieties of iridescent colors in biological species, most of them are reflective. Here we show the rainbow-like structural colors found in the ghost catfish ( Kryptopterus vitreolus ), which exist only in transmission. The fish shows flickering iridescence throughout the transparent body. The iridescence originates from the collective diffraction of light after passing through the periodic band structures of the sarcomeres inside the tightly stacked myofibril sheets, and the muscle fibers thus work as transmission gratings. The length of the sarcomeres varies from ~1 μm from the body neutral plane near the skeleton to ~2 μm next to the skin, and the iridescence of a live fish mainly results from the longer sarcomeres. The length of the sarcomere changes by ~80 nm as it relaxes and contracts, and the fish shows a quickly blinking dynamic diffraction pattern as it swims. While similar diffraction colors are also observed in thin slices of muscles from non-transparent species such as the white crucian carps, a transparent skin is required indeed to have such iridescence in live species. The ghost catfish skin is of a plywood structure of collagen fibrils, which allows more than 90% of the incident light to pass directly into the muscles and the diffracted light to exit the body. Our findings could also potentially explain the iridescence in other transparent aquatic species, including the eel larvae ( Leptocephalus ) and the icefishes (Salangidae).

To resolve Pt-dependency problems in energy convention systems, we provide an idea for construct a highly active 3D interconnected hierarchical porous graphene mesh (3D-PGM) with effective exposure active sites. By a facile controllable process through self-assembly and chemical etching of reduced-graphene oxide, synergetic enhancement of oxygen reduction reaction (ORR) performance from intrinsic activity to apparent activity was realized. The as-obtained materials exhibit 3D interconnected hierarchical porosity for efficient mass transport, a high surface defect content with increased numbers of active sites and a robust conductive network, leading to a comprehensive multiscale electron transfer capability that ultimately enhances the ORR catalytic activity. Incredibly, the alkaline ORR performance of as-obtained catalyst exhibits a 4-electron pathway reaction with an onset potential (Eonset) of 0.89 V, half-wave potential (E1/2) of 0.84 V, and a lower Tafel slope of 58 mV dec−1, showing activity comparable to that of Pt/C catalysts. Moreover, the as assembled primary Zn–air batteries (ZABs) demonstrate a higher power density (182.6 mW cm−2) and a higher specific capacity (809.1 mA h g−1) than the Pt/C-based counterpart. The outstanding electrochemical performance and facile fabrication techniques make this material a promising alternative to commercial Pt/C for renewable energy devices.

Originated at heterogeneous interfaces with distinct coefficient of thermal expansion (CTE), thermal mismatch stress is one of the critical influential factors to mechanical properties of metal matrix composites (MMCs). This stress is normally accommodated plastically by various defects, for example, high-density dislocations and twins in Al near heterogeneous interfaces in SiC/Al composites. Basic knowledge on the influence of defect characteristics is important but difficult to extrapolate from experimental results. However, existed theoretical models more focus on the influence of dislocation density, but less focus on defects variety, volume and distribution. In this paper, we propose a physics-based crystal plasticity model that has the capability of dealing with thermal mismatch stress induced dislocations and twins (denoted as TMDT model). The proposed TMDT model that is implemented in the Visco-Plastic Self-Consistent (VPSC) method considers defect heterogeneous distribution (gradient range), defect type (dislocations vs. twins) and defect volume fraction (twin spacing vs. twin volume). We demonstrate the validity and the capability of the VPSC-TMDT model in SiC/Al composites with thermal mismatch induced dislocations or twins. Furthermore, this model predicts the ultra-high strength of Graphene/Copper composites with high-density nanoscale twins, which is in turn the future aim for such nanocomposites.

High-temperature tensile testing and X-ray microscope (XRM) characterization were performed to assess the effects of the micro-addition of Gd and the three-dimensional (3-D) network structure on the improvement of Al-6Cu-3.5Ni-0.8Fe alloy under as-cast conditions. Gd addition contributed to the modification of the microstructure, where a new thermally stable micro-sized Al3CuGd phase was formed, and the refinement occurred in Al3CuNi and Al9FeNi. The tensile test results revealed that the alloy modified with 0.4 pct Gd exhibited optimal properties at 623 K (350 °C), with an ultimate tensile strength, yield strength, and elongation of 74.1 MPa, 61.2 MPa, and 15.5 pct, respectively. Fractographic analysis after the tensile tests indicated that at ambient temperature, brittle cleavage-type fracture of the precipitates and ductile fracture of the matrix were dominant, whereas the transformation from mixed fracture to fully ductile trans-crystalline fracture was detected at elevated temperatures. According to the CT characterization, there was no significant difference in the curvature or interconnectivity of the 3-D network structure formed by the aluminides between before and after the tensile test at 623 K (350 °C). It is believed that the 3-D continuous network structure of aluminides, equipped with excellent heat resistance, plays a pivotal role in the high-temperature performance of the studied alloys. This work provides a new and promising idea for solving the current heat resistance problems of cast Al alloys.

Owing to the high strength of copper (Cu) and high in-plane thermal conductivity (Kr) of graphene (Gr), Gr/Cu composites are increasingly demanded as the advanced thermal management materials to ensure the heat dissipation. The heat transport performance is primarily influenced by two aspects: (1) Intrinsic parameters of Gr, including its crystallinity, layer number (N), coverage and spatial distribution and (2) Gr/Cu interface related properties, such as interface bonding, residual strain and defects near the interface. In this work, by combining roll-to-roll (R2R) chemical vapor deposition (CVD) and subsequent hot isostatic pressing (HIP) techniques, highly paralleled Gr reinforced Cu matrix composites with controllable N were fabricated. Experimental results show that ~5–6L Gr/Cu composites manifest the highest degree of anisotropy, including (1) the highest Kr (394 ± 5 W/mK, ~22% higher than pure Cu counterpart), and (2) the lowest through-plane thermal conductivity (Kz) (257 ± 4 W/mK, ~25% lower than pure Cu counterpart). When N varies from 1 to 5, the continuously increased Kr and decreased Kz are majority influenced by intrinsic properties of Gr, which is also validated by multiscale simulations and time-domain thermoreflectance analysis. When N increases to ~10, both Kr and Kz exhibit opposite trend, that may attribute to the reduced Gr coverage and large volume fraction of amorphous carbon. Moreover, the residual strain and defects at the interface could lower both Kr and Kz as well. This study suggests that advanced synthesis of high-crystallinity thick Gr may be promising to obtain superb Kr in Cu matrix composites.

Temperature is a fundamental parameter for all forms of lives. Natural evolution has resulted in organisms which have excellent thermoregulation capabilities in extreme climates. Bioinspired materials that mimic biological solution for thermoregulation have proven promising for passive radiative cooling. However, scalable production of artificial photonic radiators with complex structures, outstanding properties, high throughput, and low cost is still challenging. Herein, we design and demonstrate biologically inspired photonic materials for passive radiative cooling, after discovery of longicorn beetles’ excellent thermoregulatory function with their dual-scale fluffs. The natural fluffs exhibit a finely structured triangular cross-section with two thermoregulatory effects which effectively reflects sunlight and emits thermal radiation, thereby decreasing the beetles’ body temperature. Inspired by the finding, a photonic film consisting of a micropyramid-arrayed polymer matrix with random ceramic particles is fabricated with high throughput. The film reflects ∼95% of solar irradiance and exhibits an infrared emissivity >0.96. The effective cooling power is found to be ∼90.8 W⋅m(−2) and a temperature decrease of up to 5.1 °C is recorded under direct sunlight. Additionally, the film exhibits hydrophobicity, superior flexibility, and strong mechanical strength, which is promising for thermal management in various electronic devices and wearable products. Our work paves the way for designing and fabrication of high-performance thermal regulation materials.

An approach for selecting alloying elements to control the size of an in situ formed phase is proposed based on a G–D map, which is derived from basic thermodynamic and kinetic principles. The G–D map is divided into four zones. Elements in Zone III are potential refiners whereas those in Zone II should be avoided in processing. When applied to the Mg2Si/Mg system, we find that Sr, P, Sb and Sn refine Mg2Si by increasing the nucleation rate and inhibiting the growth rate. Conversely, Ti, Mn, Zr and V contribute to coarse-shaped Mg2Si by postponing nucleation. The content of alloying elements should be matched with the Si content, and the required amount can be pre-estimated from the G–D map. Mg2Si formed in Mg-Al and Mg-Zn alloy is smaller than that in Mg-Si and Mg-Mn alloy, because Al and Zn suppress the diffusion of Si, particularly at high Si contents. The predictions of this approach are consistent with experimental observations. Hence, the G–D map can provide useful guidance for quantitative phase refinement design.

Streptococcus thermophilus, a Gram-positive (G+) bacterium featuring a teichoic acid-rich cell wall, has been employed as both a phosphorus source and template to synthesize a biomorphic Co2P-Co3O4/rGO/C composite as an efficient electrocatalyst for the oxygen reduction reaction (ORR). Different from the conventional method for the synthesis of phosphides, bio-derivative phosphorus vapor was emitted from the inside out, which facilitated the in situ transformation of the chemically adsorbed Co precursor on the bacteria into Co2P-Co3O4 heterogeneous nanoparticles, which featured a Co2P-rich body and Co3O4-rich surface. Besides, reduced graphene oxide (rGO) was also introduced in the synthetic process to keep Co2P-Co3O4 scattered and further promote the electron transport efficiency. All the Co2P-Co3O4 nanoparticles and rGO sheets were supported on the bacteria-derived carbon substrate with submicron-spherical morphology. The as-obtained Co2P-Co3O4/rGO/C composite exhibited excellent electrocatalytic performance for ORR with onset and half-wave potentials of 0.91 and 0.80 V vs. RHE, respectively. Furthermore, its long-term stability and methanol tolerance were better than those of commercial Pt/C. Thus, this work presents a new strategy of using an interior bio-phosphorus source to obtain heterojunction particles featuring a phosphide-rich body and oxide-rich surface, which may provide some insights for the construction of efficient heterogeneous electrocatalysts.

On the urgency of metal-free catalysts, two-dimensional materials (2DMs) have caused extensive researches because of distinctive optical and electronic properties. In the last decade, microwave methods have emerged in rapid and effective preparations of 2DMs for catalysis. Microwave heating offers several advantages namely direct, fast, selective heating and uniform reaction temperature compared to conventional heating methods, thus bringing about high-yield and high-purity products in minutes or even seconds. This review summarizes recent advances in microwave-assisted preparations of 2DMs-based catalysts and their state-of-the-art catalytic performances. Microwave heating mechanisms are briefly introduced mainly focusing on microwave-matter interactions, which can guide the choice of precursors, liquid media, substrates, auxiliaries and experiment parameters during microwave radiation. We especially provide a detailed insight into various microwave-assisted procedures, classified as exfoliation, synthesis, doping, modification and construction towards different 2DMs nanomaterials. We also discuss how microwave affects the synthetic composition and microstructure of 2DMs-based catalysts, thereby deeply influencing their optical and electronic properties and the catalytic performances. Finally, advantages, challenges and prospects of microwave-assisted approaches for 2DMs nanomaterials are summarized to inspire the effective and large-scale fabrication of novel 2DMs-based catalysts.

To enable the theoretically appealing Li–S electrochemistry in battery, the issues of the low conductivity and volume variation of the active materials as well as the intermediates diffusion need to be comprehensively addressed, which calls for rational structure design of multifunctional host material for sulfur. Herein, a novel strategy is proposed to construct 3D graphene-based N-doped porous carbon for Li–S batteries. In this strategy, interconnected macropore channels, abundant mesopores and highly accessible micropores are synergistically integrated into a conductive framework constructed by crumpled carbon sheets, and a high content of N-doping (∼18 at%) is simultaneously achieved. The obtained porous carbon possesses 3D conductive network, interconnected hierarchical porosities as well as large polarized specific surface, which endow the carbon matrix multifaceted structural merits for electrons/ions transfer, sulfur accommodation, and polysulfides immobilization. The obtained carbon sulfur composite exhibits a high reversible capacity of 1280 mA h g−1 at 0.2C, remarkable rate capabilities up to 3C and a prolonged cycling life over 500 cycles at 1C, showing intriguing promise for constructing high energy density Li–S batteries. This strategy provides a new perspective to porosity engineering and surface chemistry modification of carbon-based sulfur hosts and also other electrochemical electrode material.

Elastic strain engineering is an important strategy to design material properties in semiconductor and emerging advanced manufacturing industries. Recently, peak-pair method has drawn great attention compared to geometric phase analysis, owing to its precise determination of atom position at real space. Most current strain characterization methods estimate the local strain by comparing it with the related information from unstrained areas as reference. However, peak-pair method generated large errors in some cases because of the complexity of lower symmetric crystal structures, such as hexagonal structure. In this study, we introduce a new algorithm to overcome this limitation by directly comparing the atom positions with multiple references with different lattice symmetries. Furthermore, this new method is validated through several complicated crystal systems such as hexagonal, orthorhombic, monoclinic, and tetragonal structure, and returns expected values. This finding is essential to reliably determine the localized elastic strain with various crystal structures.

Design and synthesis of multifunctional sulfur hosts with comprehensively addressed conductivity, porosity and polarity is vital but challenging in the development of high-performance lithium-sulfur batteries. In this work, densely integrated Co,N-codoped graphene@carbon nanotubes porous hybrids (Co,N-G@CNT) are prepared as high-efficiency sulfur hosts for lithium sulfur batteries via reductive pyrolysis of (Co,Zn)-bimetallic zeolitic imidazolate frameworks separated graphene oxide sheets. The obtained Co,N-G@CNT possesses 3D interconnected conductive network, large nanopore volume and high accessible surface area as well as enriched doping sites, which endow the carbon matrix multifaceted abilities for sulfur accommodation and electron/ion transfer as well as polysulfides immobilization. Due to the rational structure design of the host material, the Co,N-G@CNT/S composite exhibits high sulfur utilization (1398 mA h g−1 at 0.2C), excellent rate capability (611 mA h g−1 at 6 C) as well as remarkable cycling stability (retained 659 mA h g−1 at 1C after 1500 cycles). This work provides a new perspective to function-directed structure design of sulfur hosts for lithium-sulfur batteries, and also holds great promise for the application in other energy storage/conversion systems such as metal air batteries, supercapacitors, and electrochemical catalysts.

The synthesis of low-cost, environmentally-friendly, and stable non-noble metallic catalyst for oxygen reduction reaction (ORR) is quite important in electrochemical fields, for ORR is the essential cathodic process in fuel cells. Here, we report a simple and general method to fabricate Co3O4 nanoparticles supported on porous carbon using butterfly wings as template and carbon source. The as-synthesized catalyst shows excellent catalytic activity for oxygen reduction with its performance close to commercial 20 wt% Pt/C. Compared to free Co3O4 particles, the enhanced performance mainly comes from the synergistic effect of Co3O4 and bio-carbon substrate. The carbonized butterfly wing shows unique porous structure with both high surface area and good connectivity, providing a firm and conductive support for active oxide nanoparticles. This work is expected to provide new ideas for the development of other porous carbon-based ORR catalysts.

Synthesis of multifunctional sulfur host material with comprehensive abilities of sulfur accommodation, electron/ion transfer and polysulfides confining is vital and challenging to bring the theoretical merits of lithium sulfur battery to practical application. Herein, a facile strategy is demonstrated to prepare 3-dimensional hierarchical porous nitrogen doped graphene as a sulfur host material for lithium sulfur battery, where urea is employed as both nitrogen doping source and self-removed template for pore structure optimization. The resultant material possesses high nitrogen doping content, 3-dimentional interconnected hierarchical porosity and conductive network and robust mechanical structure, which give rise to a comprehensive ability for multiscale electron/ion transfer, sulfur accommodation and polysulfides confining. Benefiting from the rational structure design, the sulfur loaded composite exhibits high sulfur utilization (1311 mA h g−1 at 0.2 C), high rate capability (950, 762 and 580 mA h g−1 at 1, 2 and 3 C respectively) and excellent cycling stability with high sulfur mass loading (714 mA h g−1 at 1.5 mA cm−2 after 400 cycles for a sulfur loading of 4 mg cm−2). The outstanding electrochemical performance, scalable fabrication process, and compatibility with industrial slurry-coating process makes it an ideal host material for practical application of lithium sulfur battery.

In this article, we developed a three-dimensional multi-particle finite element model to explore the effects of particle size, morphology and interfacial strength on the elastic-plastic behavior of particle-reinforced composites under uniaxial tension. We adopted strain-gradient plasticity to evaluate the size-dependent strengthening effect on matrix. Randomly distribution of spherical or cubic particles was realized in a cubic representative cell and interface damage was described by the cohesive zone model . Numerical analysis quantified the effects of microstructural features on interface damage, load transfer and strengthening effect in matrix: the flow strength of composites increases with decreasing particle size, which is attributed to the increased size-dependent strengthening in matrix, considering that the load bearing capacity of particles is decreased simultaneously. Weaker interface results in earlier and faster development of interface damage, and as the interface damage grows to the order of 0.1, load bearing capacity of particles drops from its peak value.

Structural whiteness, stemming from biologically evolutionarily refined structures, provides inspiration for designing promising, reflectance-based materials. White beetles Goliathus goliatus, which can survive in high-temperature-equatorial forests, may suggest undiscovered new physical mechanisms for thermoregulation. Their scales' whiteness is created by the exquisite shell/hollow cylinder structure with two thermoregulatory effects, contributing to a lower equilibrium temperature of elytra under direct sunlight. In the visible regime, they enhance the broadband omnidirectional reflection significantly by synergetic structural effects originating from the thin-film interference, Mie resonance and total reflection. In the mid-infrared (MIR) regime, white scales act as antireflective layers to increase the emissivity in the MIR range, enabling the elytra to reradiate heat to the environment and help the beetles reduce their temperature by as much as ∼7.8 °C in air. These biological strategies for thermoregulation could provide new approaches for bioinspired coatings towards passive radiative cooling.

Metamaterial emitters with spectrally tunable radiation in the mid-infrared region have aroused great interest in thermal management engineering applications. Nevertheless, it is still a great challenge to economically and conveniently manufacture easily scalable thermal emitters with wide-range tunable spectra. This work theoretically and experimentally demonstrates a conceptually simple and absorption-tunable design strategy for thermal emitters with tailorable spectral responses in the mid-infrared wavelength, based on the nanocomposite structure. This strategy introduces aluminum-doped zinc oxide (AZO) nanoparticles with intrinsic resonance into the top layer as an improvement to the traditional Fabry-Perot resonance system, and thereby excellent permittivity properties that are inaccessible to natural materials are obtained. With a field build-up generated in not just the middle spacer but also the top nanocomposite layer, the absorption bands can be tailored in a wider range. Moreover, according to the calculated relationship between the overall absorption and structural parameters, the tailorability of the absorption spectra can be achieved. As a proof of concept, infrared stealth and day-time radiative cooling performances are demonstrated based on spectrally different infrared emitters. This design and theoretical strategy leads to multipurpose metamaterials with tunable resonance responses for advanced thermal management engineering or even beyond infrared fields.

Metamaterials with spectrally selective absorptance operating in the mid-infrared range have attracted much interest in numerous applications. However, it remains a challenge to economically fabricate scalable meta-absorbers with tailorable absorptance bands. This work demonstrates a conceptually simple and low-cost yet effective design strategy to achieve spectrally selective absorption with tailorable band positions at MIR by colloidal lithography. The strategy ingeniously uses residual diameter fluctuations of circular resonators etched through monodisperse colloidal particles for achieving superposition of multiple magnetic resonances and thereby a more than doubled absorption band, which is neglected in previous works. The proposed meta-absorber features densely packed thick aluminum resonators with a rather narrow diameter distribution and enhanced capacitive coupling among them. Moreover, the tailorability of the absorption band can be achieved by a parameterized variation in the fabrication process. As a proof of concept, infrared stealth and radiative cooling are demonstrated based on our meta-absorbers. The design and fabrication strategy create versatile metamaterials for advanced radiative thermal engineering.

In this research, the Poisson’s ratio of three different types of almost isotropic interpenetrating composites are designed to be either positive, or negative, or zero. As they are strengthened by a self-connected fibre-network and do not contain any pore in their structure, they all are stiffer than the conventional particle composites. In addition, structural hierarchy is also demonstrated to be able to significantly enhance the auxetic behaviour for the three types of interpenetrating composites. Thus, these composites could be used not only as functional materials, but also as structural materials in engineering applications.

Streptococcus thermophilus, a Gram-positive (G+) bacterium featuring a teichoic acid-rich cell wall, has been employed as both a phosphorus source and template to synthesize a biomorphic Co2P-Co3O4/rGO/C composite as an efficient electrocatalyst for the oxygen reduction reaction (ORR). Different from the conventional method for the synthesis of phosphides, bio-derivative phosphorus vapor was emitted from the inside out, which facilitated the in situ transformation of the chemically adsorbed Co precursor on the bacteria into Co2P-Co3O4 heterogeneous nanoparticles, which featured a Co2P-rich body and Co3O4-rich surface. Besides, reduced graphene oxide (rGO) was also introduced in the synthetic process to keep Co2P-Co3O4 scattered and further promote the electron transport efficiency. All the Co2P-Co3O4 nanoparticles and rGO sheets were supported on the bacteria-derived carbon substrate with submicron-spherical morphology. The as-obtained Co2P-Co3O4/rGO/C composite exhibited excellent electrocatalytic performance for ORR with onset and half-wave potentials of 0.91 and 0.80 V vs. RHE, respectively. Furthermore, its long-term stability and methanol tolerance were better than those of commercial Pt/C. Thus, this work presents a new strategy of using an interior bio-phosphorus source to obtain heterojunction particles featuring a phosphide-rich body and oxide-rich surface, which may provide some insights for the construction of efficient heterogeneous electrocatalysts.

Vanadium dioxide (VO2) is considered one of the most promising smart thermal control materials due to its insulator-metal temperature (IMT) reversible phase transition, accompanied by large changes in its optical properties. However, as the crystal defects on IMT change and the optical property of VO2 is still unclear, the preparation of doped VO2 films by magnetron sputtering is still a great challenge. In this work, the IMT of 41 kinds of doping-VO2 systems were studied by high throughput calculation based on density functional theory (DFT). It was found that the IMT increased with the decrease of the β angle in M phase and expansion of cell volume difference of M-phase and R-phase for IIA elements, VIIA elements, transition elements, and rare earth element doped VO2, and increased with the increase of the β angle in M phase and a decrease of cell volume difference of M-phase and R-phase for IA, IVA, VA, and VIA element doped VO2. According to the rule, the IMT, electronic structures, and optical properties of W doped VO2 were studied based on DFT. The results show that IMT and bandgap decrease with the increase of W6+ ion concentration, which is due to the increased cell volume difference of M-phase and R-phase in W doped VO2; each doped atom can reduce the IMT of 20.2 °C, and the IMT of V0.98W0.02O2 is close to room temperature (Tc ≈ 27 °C). The rate of infrared emissivity (∆ɛ) of V0.98W0.02O2 is about 0.2 at 8–14 μm (0.088–0.155 eV) and the average solar absorption (αs) of M phase and R phase is about 0.53 and 0.59 at 0.3–1.5 μm (0.496–4.13 eV), respectively. Finally, radio frequency magnetron sputtering was used to achieve precise doping, which solved the problem of oxygen partial pressure in reactive magnetron sputtering, and V1-xWxO2 films with IMT close to room temperature and narrow hysteresis width were prepared. This is due to the fact that higher W doping content will greatly increase the density of defect-induced nucleation sites and promote nucleation. At the same time, the experimental results of IMT were consistent with the calculated results, which proved the reliability of the calculation. This will provide a theoretical basis for the development of new thermal control materials and a new method for the preparation of doping-VO2 films in the future.

Amorphous Ni-P with elaborate hollow dendritic architecture is fabricated using Morph butterfly-wing scales as template by electroless deposition method. The electrocatalytic performance for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is characterized in alkaline solution. As an anode material, the catalyst shows excellent OER catalytic activity with a low Tafel slope of 67.3 mV dec−1 and a low overpotential of 303 mV to reach 20 mA cm−2, which is comparable to RuO2. As a cathode material, the as prepared Ni-P shows relatively good catalytic performance for HER with a moderate Tafel slope of 75.2 mV dec−1 and an overpotential of −176 mV to deliver 20 mA cm−2. Employing the bifunctional catalyst as anode and cathode material in a two electrode system, a cell voltage of 1.63 V is required to reach an overall water splitting current density of 10 mA cm−2 with good electrochemical stability. The excellent performance should be attributed to the coupling effect of the Ni-P composition with amorphous and P compositing feature and the hollow dendritic architecture with high accessible surface area.

The influences of rigid heterointerfaces on the dynamic recrystallization (DRX) process and texture evolution during hot rolling of a graphene nanoribbon (GNR)-reinforced Cu-matrix composite system are investigated. The Cu/GNR interfaces contribute to the atypical recrystallization-type and brass-type textures developed in composites within 0.5 and 3 vol pct GNRs, respectively, deviating from the normal Cu-type texture found in their pure Cu counterpart. The heterointerfaces may change the texture evolution of the Cu matrix in four ways, namely, retard the dislocation cross slip, activate partial slip, generate geometrically necessary dislocations, and promote the DRX process. These are corroborated through viscoplastic self-consistent simulations, which well reproduce the texture development in all samples by considering the interface–dislocation interactions, the activation of non-normal slip, and the interface-driven DRX nucleation. This study suggests the possibility of manipulating the microstructure, texture, and mechanical properties of traditional metallic materials through the design of heterophase interfaces.

Layered materials beyond graphene have generated renewed interests in numerous fields. Liquid-phase exfoliation methods face essential challenges in their universal application toward various two-dimensional materials (2DMs), short processing time, high yield, chemical stability, ultrathin thickness, and large lateral size of the nanosheets. To date, few reported methods are satisfactory in these requirements. We develop a general microwave-assisted, rapid (30 min), efficient (up to 50% yield), and potentially scalable approach to exfoliate 2DMs into mono- and few-layer nanosheets of superior chemical stability and large lateral size. 2DMs including h-BN, g-C3N4, BP, TMDs (MoS2, WS2, MoSe2), Zn2(bim)4, and Ti3C2Tx are tested for exfoliation in different fluid media including organic solvents and PF6–-containing ionic liquids (ILs). The nanosheets (e.g., BP) are surprisingly stable, probably attributed to solvation shells preventing the exfoliated sheets from reacting with water and oxygen. Theoretical simulations reveal that the dielectric constant of the fluid medium is a key factor determining the exfoliation efficiency. The preferred fluid media should be strongly polar (e.g., organic solvents with a high dielectric constant), which indicates materials’ ability to store electromagnetic energy via polarization. Finally, we demonstrate the 3D printing of nanosheet-based hybrids for potential applications. This general strategy paves a new promising pathway for the efficient liquid exfoliation of various 2DMs.

Interfacial debonding is detrimental for the properties of diamond/Cu composites, which can be solved by diamond surface metallization with active element Cr. Using microstructure characterization and statistical investigation, we find that the diamond surface metallization undergoes dispersed growth, preferred growth, complete metallization and preferred cleavage. The preferred carbide growth on {100} surfaces and preferred carbide cleavage on {111} surfaces result from the different surface configurations. Furthermore, an amorphous carbon layer generates at diamond (111)/carbide interface for the structure transformation. Interfacial bonding between diamond and Cu is realized via reaction bonding at diamond/carbide interface and diffusion bonding at carbide/Cu interface.

MnO2/C composite with 3D hierarchical ridge/straight-pore/nano-grid architecture (RPG-MnO2/C) is fabricated using Parides sesostris butterfly wings as both template and carbon source via a carbonizing-surface reaction process. The self-supported RPG-MnO2/C as supercapacitor electrode shows a maximum specific capacitance of 1539.7 F g−1 at 1 A g−1, which is among the highest values ever reported for MnO2. Excellent cycling stability retaining 97.6% of its initial capacitance after 10000 charge-discharge cycles at 10 A g−1 is also exhibited, together with ~100% coulomb efficiency. This outstanding performance can be attributed to the coupling effect of double-component composition (carbon substrate, MnO2 nanolayer) and multiscale hierarchical architecture (microscale ridges, sub-microscale straight pores, nanoscale grids).

Graphene-based mixed-dimensional materials hybridization is important for a myriad of applications. However, conventional manufacturing techniques face critical challenges in producing arbitrary geometries with programmable features, continuous interior networks, and multimaterials homogeneity. Here we propose a generalized three-dimensional (3D) printing methodology for graphene aerogels and graphene-based mixed-dimensional (2D + nD, where n is 0, 1, or 2) hybrid aerogels with complex architectures, by the development of hybrid inks and printing schemes to enable mix-dimensional hybrids printability, overcoming the limitations of multicomponents inhomogeneity and harsh post-treatments for additives removal. Importantly, nonplanar designed geometries are also demonstrated by shape-conformable printing on curved surfaces. We further demonstrate the 3D-printed hybrid aerogels as ultrathick electrodes in a symmetric compression tolerant microsupercapacitor, exhibiting quasi-proportionally enhanced areal capacitances at high levels of mass loading. The excellent performance is attributed to the sufficient ion- and electron-transport paths provided by the 3D-printed highly interconnected networks. The encouraging finding indicates tremendous potentials for practical energy storage applications. As a proof of concept, this general strategy provides avenues for various next-generation complex-shaped hybrid architectures from microscale to macroscale, for example, seawater desalination devices, electromagnetic shielding systems, and so forth.

The hot deformation behaviors of 50 vol pct uncoated and Cr-coated diamond/Cu composites were investigated using hot isothermal compression tests under the temperature and strain rate ranging from 1073 K to 1273 K (800 °C to 1000 °C) and from 0.001 to 5 s−1, respectively. Dynamic recrystallization was determined to be the primary restoration mechanism during deformation. The Cr3C2 coating enhanced the interfacial bonding and resulted in a larger flow stress for the Cr-coated diamond/Cu composites. Moreover, the enhanced interfacial affinity led to a higher activation energy for the Cr-coated diamond/Cu composites (238 kJ/mol) than for their uncoated counterparts (205 kJ/mol). The strain-rate-dependent constitutive equations of the diamond/Cu composites were derived based on the Arrhenius model, and a high correlation (R = 0.99) was observed between the calculated flow stresses and experimental data. With the help of processing maps, hot extrusions were realized at 1123 K/0.01 s−1 and 1153 K/0.01 s−1 (850 °C/0.01 s−1 and 880 °C/0.01 s−1) for the uncoated and coated diamond/Cu composites, respectively. The combination of interface optimization and hot extrusion led to increases of the density and thermal conductivity, thereby providing a promising route for the fabrication of diamond/Cu composites.