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The vibration of thermodynamic machinery will affect its cooling system. In this research, a high-resolution simulation of jet impingement was performed to quantify the unsteady turbulent convection under vibration conditions. A newly developed Self-Adaptive Turbulence Eddy Simulation (SATES) method was used. The Reynolds number was Re = 23000, the jet-to-wall distance was fixed at H/D = 2, and the vibrating frequency of the impinging wall f varied from 0 Hz to 200 Hz. Compared with the static wall case, the maximum enhancement of the stagnation point and area averaged Nusselt number within r/D = 1 could reach up to 5% due to the larger primary vortices, whereas it could reduce the heat transfer by 10% beyond r/D = 3 due to the suppression of the wall vortices development. Based on the unsteady analysis and Proper Orthogonal Decomposition (POD) pattern, the modes controlled by vibration were recognized and their contributions to the heat transfer performance were also evaluated. The introduction of the vibration promoted the development of the primary vortices and changed the radial alternating motion to a vertical alternating motion at the wall jet region. The former was beneficial for the heat transfer, while the latter was unfavorable.

Metal rich-sulfides, with remarkable theoretical capacity, still suffer from the disolving of polysulfides and sluggish kinetics. Electrocatalysts, as the vital meditors, have been applied in Li-S systems with notable improvements, but scarcely explored for ions-storage battery. Herein, for introducting cation-tunable MOx (M=Mn/Fe/Co/Ni) as electrocatalysts, various MoS2@MOx are designed through chemical-precipitation and thermal-treatment manners. Benefitting from the high affinity of MoS2 and MOx, the interfacial chemical bonds Mo-S-M are established, boosting the improvement of ions/electrons transferring and structural integrality. Owing to the evolution of outer orbitals and ionic radius, the capturing and conversion of Li2S8 are tailored in order of Fe2O3>MnO>CoO>NiO. Supported by unique 3d-orbital/ion-radiu and Mo-S-Fe bonds, the ultra-fast ability of MoS2@Fe2O3 remains ∼612 mAh g−1 after 3,000 loops even at 5.0 A g−1, meanwhile delivering ∼800 mAh g−1 at 0.5 A g−1 in full-cell. Assisted by detailed kinetic behaviors and theoretical calculations, the redox reaction mechisms are clearly proposed, whilst the reduced Gibbs free energy (-1.25 of Fe2O3) serves crucial roles in the reaction (Li2S8 → Li2S6). This work is expected to shed light on the in-depth understanding of fourth-periods MOx electrocatalysts, and offers more possibilities for designing advanced metal-sulfides electrodes. MoS2 nanosheets uniformly anchored with MOx (M=Mn, Fe, Co, Ni) were rationally engineered, accompanied by the establishment of Mo-S-M interfacial chemical bonds. The electrocatalytic abilities of introduced MOx were successfully tailored by the evolution of cationic outer orbitals and ionic radius, inducing the fascinated catalytic conversion behaviors.

The energy-conversion storage systems serve as crucial roles for solving the intermittent of sustainable energy. But, the materials in the battery systems mainly come from complex chemical process, accompanying with the inevitable serious pollutions and high energy-consumption. Natural mineral resources display various merits, such as unique architecture, adsorption capability and rich active sites, which have captured numerous attentions with remarkable advancements. Recently, the minerals compounds, containing 1D structure (halloysites, attapulgites, sepiolite), 2D structure (montmorillonite, vermiculite, molybdenite) and 3D structure (diatomite, pyrites), have been applied in plenty of fields. Aiming at their energy-storage applications, the significant utilizations in electrodes, separators, electrolyte and metal-protection were detailedly reviewed in lithium-ions battery, lithium-sulfur battery, solid-state battery and so on. However, it should be acknowledged that, the simple minerals hardly meet the demand of energy-storage systems, due to their inferior conductivity and less active substances. Thus, series of modified manners are applied for the evolution of phase (from silicate mineral to Si), the incorporating with carbon/polymer and the tailoring of surface traits, which were in-depth discussed as following. The work was expected to summarize the traits about mineral compounds from different architectures, whilst offering significant guidelines for exploring mineral-based materials in energy-storage systems.

The conversion of molecular dinitrogen into ammonia is one of the most important chemical processes, which involves the inert N≡N bond activation and multi-step hydrogenation. For the requirements of complicated catalytic processes, single-cluster catalysts (SCCs) have emerged as a promising platform to trigger the synergistic effects. Herein, we present a systematic investigation on the stability and activity of a series of singly dispersed bimetallic catalysts, M1Con/CoOx SCCs, for the hydrogenation of dinitrogen by first-principles calculations. Our results indicate that the late transition metals are prone to form stable singly dispersed bimetallic clusters by doping the O vacancy on CoO surfaces. Due to the low oxidation state of the doped metals in the stable M1Con/CoOx SCCs, the chemisorption of N2 is enhance by the multiple “pull–push effect” of the isolated bimetallic sites. Subsequently, an improved electron descriptor (μ) is proposed to effectively estimate the correlation between the favorable bridging N2 adsorption energies and the essential electronic characteristics of M1Con/CoOx SCCs, in which the influence of the metal d orbital electrons and the intrinsic 1st ionization energy are considered. We focus on the first hydrogenation in the associative mechanism on the multicenter of M1Con/CoOx SCCs, and the Pd1Co4/CoOx SCC is proposed to exhibit superior charge buffer capacity towards thermal dinitrogen hydrogenation. Furthermore, a superimposed evaluation strategy associates the activity of nitrogen fixation on SCCs with certain intrinsic features of multi-active sites at both static and kinetic states. The present work not only provides a potential candidate for the thermal N2-to-NH3 conversion, but also sheds insights into the rational design of heterogeneous catalysts for thermal nitrogen fixation.

Three RF switches and a phase shifter are proposed using the conductive bridging random access memory (CBRAM) technique. The fabrication process is developed with the Nafion membrane on a high-resistivity silicon substrate. The equivalent circuit model is established for each memristive RF switch. The proposed switches and the phase shifter have been validated by the good agreement achieved among the simulated, measured, and modeled results. The experimental results show that the series planar switch has the ON-state insertion loss (IL) below 1.69 dB and the OFF-state isolation over 25 dB up to 10 GHz, with the actuation voltages of 6.1~7.8/-1.5~-2 V. The parallel metal-insulator-metal (MIM) switch has the small ON-state IL below 0.45 dB and the OFF-state isolation over 18.4 dB when biased with 0.8~3.7/-0.5~-0.9 V. The series MIM switch has the ON-state IL below 0.61 dB and the OFF-state isolation over 21.9 dB with 0.7~2.3/-0.5~-0.9 V. The series MIM switch shows a good comprehensive performance of low actuation voltage, good uniformity, low IL, moderate isolation, and independent control. The phase shifter is realized with four series MIM switches, which provides a phase shift of 45° ± 5° from 3.8 to 4.3 GHz with the in-band IL of 2.25 dB. Compared with the conventional RF switchable devices, the proposed devices have the advantages of nonvolatility and low power consumption. Without depending on the electron beam lithography process and high-temperature phase change, the proposed technique is promising for reconfigurable RF circuits with mass production and feasibility to various substrates.

As a typical transition metal oxide anode material, ZnMoO4 can deliver a higher theoretical capacity of 951.6 mAh g−1 due to its variable oxidation state and alloying reaction. However, lower conductivity and huge volumetric expansion restrict its further development. Herein, the modified sol–gel method is applied to synthesize a series of (1-x)ZnMoO4-xZnFe2O4 (x = 0.1, 0.2, 0.3, 0.4, and 0.5) composites. The effects of compound proportion of ZnFe2O4 on the crystal phase structure and morphology for ZnMoO4 have been investigated in detail. All the composites have been conducted on electrochemical measurements, and the results illustrate that the composites display better electrochemical performance than that of ZnMoO4. Especially for 0.6ZnMoO4-0.4ZnFe2O4, it can deliver a capacity of 550.7 mAh g−1 after 500 cycles at a current density of 200 mA g−1. Moreover, it also presents the higher capacity at higher current density. The improvement of electrochemical performance should be attributed to the synergistic effect of ZnFe2O4 and ZnMoO4.

The core-shell 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane/2,4,6-Trinitrotoluene (CL-20/TNT) composite was prepared by spray-drying method in which sensitive high energy explosive (CL-20) was coated with insensitive explosive (TNT). The structure and properties of different formulations of CL-20/TNT composite and CL-20/TNT mixture were characterized by scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Laser particle size analyzer, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), differential scanning calorimetry (DSC), impact sensitivity test and detonation performance. The results of SEM, TEM, XPS and XRD show that ϵ-CL-20 particles are coated by TNT. When the ratio of CL-20/TNT is 75/25, core-shell structure is well formed, and thickness of the shell is about 20–30 nm. And the analysis of heat and impact show that with the increase of TNT content, the TNT coating on the core-shell composite material can not only catalyze the thermal decomposition of core material (CL-20), but also greatly reduce the impact sensitivity. Compared with the CL-20/TNT mixture (75/25) at the same ratio, the characteristic drop height of core-shell CL-20/TNT composite (75/25) increased by 47.6% and the TNT coating can accelerate the nuclear decomposition in the CL-20/TNT composites. Therefore, the preparation of the core-shell composites can be regarded as a unique means, by which the composites are characterized by controllable decomposition rate, high energy and excellent mechanical sensitivity and could be applied to propellants and other fields.

In this study, we report the effects of hydroxypropyl methylcellulose (HPMC) and KH2PO4 on the water resistance of magnesium oxychloride cement (MOC), a novel bone cement composite. Different MOC samples were soaked in simulated body fluid (SBF). After soaking for 7 to 56 d, the surfaces of the experimental group (1 wt.% HPMC/2 wt.% KH2PO4-MOC) and control group (2 wt.% KH2PO4-MOC) appeared pores, which grew with increasing immersion time. Compared with the control group, the experimental group had smaller pore sizes and a denser surface. Furthermore, the compressive strength in the experimental group increased from 35.1 ± 1.9 MPa to 41.8 ± 2.3 MPa, and the softening coefficient increased from 0.34 to 0.45. Thus, HPMC could improve the water erosion resistance of the MOC. The implantation study of the femoral defects in rats showed that the sample modified by 1 wt.% HPMC/2 wt.% KH2PO4 had good biocompatibility and biodegradability. The results indicate that the modification of MOC with HPMC and KH2PO4 is a promising technique to form biodegradable bone repair materials and has good application prospects in the field of biomedical materials.

Efficient recycling of high-value metals from spent cathode materials is important in that it not only alleviates the severe shortage of raw material supply but also addresses the environmental and safety issues associated with the disposal of these materials. Here, we report a selective leaching strategy by virtue of the defect-induced lattice instability. In contrast to the traditional “primary leaching – multistep separation” process, this technique enables simultaneous recovery and separation of value metals from the waste cathode by selective dissolution. The feasibility of this technique was first demonstrated by density functional theory (DFT) calculations, and then confirmed by laboratory studies in which a spent LiNi1/3Co1/3Mn1/3O2 material was successfully recycled, where the recoveries of Li, Ni/Co and Mn reached close to 100%, 99.5%/98.2% and 100%, respectively, without the need for a separation step. The recovery of Li, Ni/Co and Mn uses oxalic acid, phosphoric acid and sulfuric acid as leaching agents, respectively. We believe that this work has both practical and theoretical significance, in that the strategy has the potential to be expanded to the recovery/recycling of many other spent materials, and that the atomic-scale insight on the relation between vacancies and lattice stability offers new perspective for developing advanced recycling strategies.

Using a virus as a template to synthesize nanomaterial is a simple, green, and controllable method to acquire unique structure nanoparticles. In this study, CdS nanowires were synthesized using the tobacco mosaic virus (TMV) as a template and for deposition in the inner center channel of TMV. TMV/CdS was successfully characterized, with the results showing a diameter of 4.0 nm, a cubic-phase composition, and strong fluorescence emission peaks, with an absorption edge of 566 nm and bandgap energy of 2.28 eV. The bandgap energy is narrower than that of template-free CdS. Furthermore, TMV/CdS exhibited an increased transient photocurrent, which was attributed to the effective separation of electron-hole pairs. The photoactivities of TMV/CdS and template-free CdS were tested; the results showed that the TMV/CdS had a better performance in methylene blue (MB) photodegradation, indicating that the photoactivity of TMV/CdS was higher than that of the template-free CdS. Further research on TMV/CdS regarding the photocatalytic mechanism showed that O2•− and •OH were the major species involved in photocatalysis, rather than holes (h+). Therefore, TMV/CdS might have applications as a novel visible-light-responsive photocatalyst. • CdS nanowires were firstly synthesized in the inner center channel of TMV • TMV/CdS presented higher photocatalytic efficiency compared with template-free CdS • The O 2 •− and • OH were responsible for the photocatalytic reaction of TMV/CdS

Despite the intriguing merits of lithium-sulfur (Li-S) systems, they still suffer from the notorious “shuttling-effect” of polysulfides. Herein, carbon materials with rational tailoring of morphology and pores were designed for strong loading/adsorption with the controlling of energy-storage ability. Through rational tailoring, it is strongly verified that such engineering of evolutions result in variational of sulfur immobilization in the obtained carbon. As expected, the targeted sample delivers a stable capacity of 925 mAh g−1 after 100 loops. Supporting by the “cutting-off” manners, it is disclosed that mesopores in carbon possess more fascinated traits than micro/macropores in improving the utilization of sulfur and restraining Li2Sx (4 ≤ x ≤ 8). Moreover, the long-chain polysulfide could be further consolidated by auto-doping oxygen groups. Supported by in-depth kinetic analysis, it is confirmed that the kinetics of ion/e- transfer during charging and discharging could be accelerated by mesopores, especially in stages of the formation of solid S8 and Li2S, further improving the capacity of ion-storage in Li-S battery. Given this, the elaborate study provide significant insights into the effect of pore structure on kinetic performance about Li-storage behaviors in Li-S battery, and give guidance for improving sulfur immobilization.

Due to the strong heterogeneity, the infaust mobility ratio of offshore heavy oil reservoirs and the high cost of produced water treatment, a “green” in-depth profile control technology was proposed, which integrated produced water reinjection and microsphere in-depth profile control and displacement technology. Experimental results show that RGO-PMSs maintained to be spherical and expanded 5.2–6 time after aging 15 days in brine. While the size of RGO-PMSs aggregation increased 15–25 times, which induced the enhancement of plugging efficiency when permeability was higher than 3000 mD. During RGO-PMSs migration in porous media, it could adjust profile by adsorbing on rock surface or forming plugging in the forms of single capture, bridging, and accumulation. Due to the elastic deformation ability of RGO-PMSs, the particles could enter in-depth reservoirs to form plugging and modulate profile. Moreover, RGO-PMSs system injection and subsequent water flooding could enhance the oil recovery in high permeability layer and low permeability layer of 31.3% and 73.5%, respectively in parallels core displacement experiments. It is believed that the proposed produced water injection combined with RGO-PMSs could be a potential “green” candidate for enhancing oil recovery in offshore heavy oil reservoirs.

Polarization-sensitive photodetector based on low-dimensional semiconductor is a kind of special photoelectric device which can take advantage of the semiconductor’s anisotropy and convert it into an electrical signal. However, the polarization performance of the photodetector is limited by the challenges of the anisotropy of semiconductors. The design of alloy semiconductors with excellent anisotropy is one of the mainstream methods to improve the dichroic ratio of the polarization-sensitive photodetector. Here, we design the tunable alloying Sb–S–Se nanowires (NWs), which can be used in the research field of polarization-sensitive photodetectors because of their low symmetry crystal structure, suitable bandgap, and high mobility. It is demonstrated that the metal-semiconductor-metal polarization-sensitive photodetector based on Sb–S–Se NWs has great photoelectric properties and polarization performance in UV–Vis-near-infrared response (NIR) spectrum. Under the irradiation laser of the 532-nm, the photoresponsivity ( ${R}$ ) and detectivity ( ${D}$ *) of the Sb2(S1/3Se2/3)3 NW-based polarization-sensitive photodetector can reach 6.38 A/W and 1.63 $\times 10^{9}$ Jones. By investigating the polarization characteristics of the photodetector, the dichroic ratio of the photodetector can reach 3.8 at 532 nm. By regulating the proportion of each component in the alloy semiconductor, an effective method is provided for adjusting the photoresponse spectrum and optimizing the performance of the polarization-sensitive photodetector, which has a promising research prospect in the future.

Anomalies as misalignment, microcrack are inevitable for large diameter high strength steel pipelines. To ensure the strain capacity of mismatched welding joint with misalignments of D 1,422 mm X80 steel pipeline, a comprehensive study via wide plate experiments and finite element model simulations was conducted. The full-scale tensile experiment of a X80 pipe wide plate with weld joint was conducted. Strain distributions on the plate was derived by DIC technic. Trends of CMOD at the precrack in the weld joint with tensile strains monitored. A FE model was established to inverse the wide plate experiment and prove the accuracy of numerical model’s prediction results for crack driving forces. Using the same modeling method, a parametrical 3D numerical simulation model for X80 line pipe with cracks in automatic welding joints was established. The double V-shaped groove type welding joint was precisely considered in the geometric model. Difference of the stress-strain relationships of yielding-to-tensile ratio of the BM, softening rate of the HAZ and strength matching coefficient of WM were considered in the material model. A CTOD extracting program coded was employed. Parametric analysis was performed to investigate the effects of load conditions, strength matching coefficient of WM, yielding-to-tensile ratio of BM and softening rate of HAZ on the strain capacity with a critical fracture toughness adopted in pipeline industry. Based on the derived results, mismatched ratio requirements of D 1,422 mm X80 pipes were listed, which provides guidance for the welding parameter design and safety evaluation of automatic welding joints.

The traditional acid leaching method for recycling valuable metals from the cathode material of spent lithium-ion batteries (LIBs) has encountered the problems of high consumption of H₂SO₄ and reducing agents. In this study, a novel process has been developed to strengthen valuable metal recovery from spent lithium-ion batteries by reductive thermal treatment and electrochemical leaching. With the help of reductive thermal treatment under the conditions of R = 1600 °C and 120 min, the layered structure of the cathode material LiNi₁/₃Co₁/₃Mn₁/₃O₂ is reduced to a mixture of Li₂CO₃, NiO, Co₃O₄, Mn₂O₃, and MnO₂ due to the oxygen releasing from the framework. The destruction of the layered crystal structure reduces the difficulty of leaching valuable metals. 90.59% Ni, 90.53% Co, 66.40% Mn, and 100% Li were leached under the optimal conditions of 20 mL/g liquid–solid ratio, 1.5 M H₂SO₄, 0.8 A, and 150 min at room temperature. Comparing the processes of reductive thermal treatment with acid leaching and direct electrochemical leaching of spent cathode material under the same leaching conditions, the proposed approach can achieve the highest metal recovery and economic benefits. It can be implemented at room temperature, decreases the application of reducing agent and sulfuric acid, and makes full use of spent graphite, resulting in a greener recycling process for recovering valuable metals from spent LIBs.

Hexagonal boron nitride nanosheets (HBNNSs) have huge potential in the field of coating materials owing to their remarkable chemical stability, mechanical strength and thermal conductivity. Thin-layer hBNNSs were obtained by a liquid-phase exfoliation of h-BN powders and incorporated into EVA coatings for improving the safety performance of 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX). HBNNSs and ethylene-vinyl acetate copolymer (EVA) were introduced to HMX by a solvent-slurry process. For comparison, the HMX/EVA and HMX/EVA/graphene (HMX/EVA/G) composites were also prepared by a similar process. The morphology, crystal form, surface element distribution, thermal decomposition property and impact sensitivity of HMX/EVA/hBNNSs composites were contrastively investigated. Results showed that as prepared HMX/EVA/hBNNSs composites were well coated with hBNNSs and EVA, and exhibited better thermal stability and lower impact sensitivity than that of HMX/EVA and HMX/EVA/G composites, suggesting superior performance of desensitization of hBNNSs in explosives.

The near-infrared (NIR) polarized photodetector has wide range of applications including the object identification. Wavelength of 1550 nm is the least loss band for transmission communication, and the study of photodetectors working at 1550 nm demonstrate special scientific and applied significances. GaSb has attracted tremendous attention in the field of photoelectric detection due to its suitbale band gap, high mobility, sensitivity, and good compatibility with modern microelectronics technology. In this work, a highly polarization-sensitive GaSb nanowire-based photodetectors under short-wave near-infrared photoelectric detection is achieved. The device has a good optical detection ability in the near-infrared band, and showed the responsivity up to 77.3 A/W with the external quantum efficiency of $6.18\times 10 ^{3}$ % (illumination intensity of 1.59 mW/mm2) under 1550 nm. Furthermore, obvious photocurrent anisotropy are investigated under the near-infrared band from 808 nm to 1550 nm. The largest dichroic ratio reaches 3.3 at 1550 nm. These results indicate that GaSb nanowire based photodetectors are not only promising candidates for NIR detection but also have promising potentials in polarization sensitive applications.

The consumption of rechargeable batteries has been increasing rapidly. High demand on specific metals for battery manufacturing and environmental impacts from battery disposal make it essential to recycle and retrieve materials from the spent batteries. There have been some review articles on battery recycling, mostly on the technologies for the materials recovery and some on life cycle assessment (LCA). To develop a truly sustainable battery industry, however, battery recycling must be commercially viable. Yet, very limited information on the economics of battery recycling is available. This paper examines technologies and research efforts in battery recycling from the perspective of economic viability and life cycle inventory. With the support of up-to-date statistics, the paper also comments on the challenges facing battery recycling, and the role of battery design and circular economy in the sustainable development of battery industry where governments, manufacturers and consumers all play a part.

Theoretical calculations unveil the charge redistribution over abundant interfaces and the enhanced electronic states of Ru/RuS2 heterostructure. The resulting surface electron-deficient Ru sites display optimized adsorption behavior toward diverse reaction intermediates, thereby reducing the thermodynamic energy barriers. Experimentally, for the first time the laminar Ru/RuS2 heterostructure is rationally engineered by virtue of the synchronous reduction and sulfurization under eutectic salt system. Impressively, it exhibits extremely high catalytic activity for both OER (201 mV @ 10 mA cm-2 ) and HER (45 mV @ 10 mA cm-2 ) in acidic media due to favorable kinetics and excellent specific activity, consequently leading to a terrific performance in acidic overall water splitting devices (1.501 V @ 10 mA cm-2 ). The in-depth insight into the internal activity origin of interfacial effect could offer precise guidance for the rational establishment of hybrid interfaces.

Room-temperature (RT) sodium-sulfur (Na/S) battery has been considered as a promising energy storage system due to suitable operating temperature, high theoretical energy density, and low cost. However, it has a poor cycle life and low reversible capacity. In this work, we report a long-life RT-Na/S battery with the help of amorphous porous silica as a sulfur host. The sulfur is loaded into amorphous silica by a facile dipping method, and the optimal sulfur loading can be as high as 73.48 wt.%. The molecular dynamics simulation and first-principles calculations suggest that the complex pores, acting as micro-containers and the formation of Na-O chemical bonds between amorphous silica and sodium polysulfide, give the electrodes a strong ability to inhibit sodium polysulfide shuttle. This would give rise to effectively avoiding the loss of active sulfur, corresponding to a superior capacity (i.e., average discharge capacities of 1106, 1074, 1060, 1036, and 1000 mAh·g -1 at 1, 2, 3, 5, and 10 A·g -1 , respectively.) and an excellent cyclability even at 10 A·g -1 (nearly 100% coulomb efficiency and high reversible capacity of 955.8 mAh·g -1 after 1460 cycles). The present results introduce new insights into the inhibition of "shuttle effect" of sodium polysulfide and develop a promising sulfur electrode for advanced RT sodium-sulfur batteries.

Intrinsic polysulfide shuttling is the most fatal problem with Li-S batteries but it can be suppressed by functionalizing the separators with strong lithium polysulfide absorbents. Carbon nanotube (CNT)-supported MoSe2 nanoflakes with a large interlayer spacing were coated on a commercial polypropylene separator to build an efficient barrier (M/C-PP) to polysulfide shuttling for Li-S batteries. The battery with the separator had initial specific capacities of 1 485 and 880 mAh g−1 at 0.1 and 2 C, respectively, and an excellent long-term cycling stability with a low decay rate of 0.093% per cycle at 0.5 C after 300 cycles. This excellent performance was attributed to the strong adsorption of polysulfides by MoSe2 and the fast charge transport channels provided by the CNTs.

Theoretically, carbonaceous materials with a high degree of graphitization and large surface area are beneficial for Li+ storage, and those with a large surface area and enlarged interlayer spacing are beneficial for Na+ storage. However, synchronously realizing them in carbonaceous materials at moderate temperatures is still a huge challenge. Herein, using bifunctional silica (SiO2), as a catalyst for graphitization of carbon and template for pore-forming, we propose a strategy to enhance the graphitization and surface area of carbonaceous materials simultaneously, besides N, P co-doping. As an anode material, the obtained 3D porous carbon network shows ideal cycling stability and excellent rate capability for both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs): outstanding reversible capacities of 1038 mA h g−1 and 238 mA h g−1 are delivered separately for LIBs and SIBs at a current of 1 A g−1. Also, it demonstrates a good rate capability at a higher current of 10 A g−1 and excellent cycling stability at 5 A g−1 for 2000 cycles for LIBs and SIBs. These results illuminate the design principle of carbonaceous materials for Li and Na storage by considering the high degree of graphitization, large specific surface area and heteroatom doping, endowing LIBs and SIBs with promising performance and applications.

Due to them being widely used batteries, a boom in the disposal of LiFePO4 (LFP) batteries is coming. Both pyrometallurgical repair and hydrometallurgical processes have been applied in the recycling of spent LFP batteries. The former has limited application due to its poor adaptability for spent LIBs with different chemistries or inconsistent degrees of damage, while the latter has poor economic returns due to the low added value of its products, ferric phosphate and lithium carbonate. In this study, a facile process for directly regenerating LiFePO4 from spent LFP cathode material involving acid leaching and hydrothermal synthesis is proposed. The results indicate that the acid leaching process of the spent LFP cathode material depends on the surface chemical reaction, and that 96.67% lithium and 93.25% iron leaching efficiency can be simultaneously achieved by control of the thermodynamic conditions. Additionally, through component control and a one-step hydrothermal process, a flake-like LFP cathode material was successfully regenerated directly from the leaching solution. The regenerated LFP cathode material shows good electrochemical performance, and its discharge capacity is 136 mA h g−1 at 0.1 C. After 300 cycles at 1 C, its capacity retention ratio is as high as 98.6%. Moreover, an economic evaluation indicates that the process is profitable. Therefore, the proposed approach in this study could help to avoid the complex element separation process and achieve the facile recycling of LFP cathode material, thus providing a novel and efficient method for the clean and economical recycling of spent LFP cathodes.

Due to its high theoretical capacity (∼280 mA h g−1), lithium vanadium oxide (LiV3O8) is considered a promising electrode material for meeting the demands for a longer battery life. However, it still suffers from an inferior cycling stability and rate properties. Benefitting from the unique traits of rare earth metal La, La-doping was introduced to V-sites, leading to an expansion of the lattice volume and reduced particle size, and bringing about more oxygen defects for fast ion redox reactions. The considerable discharge capacity of optimized La-doped LiV3O8 could reach up to 308 mA h g−1, and the capacity could be kept at 252 mA h g−1 after numerous loops. Supported by a detailed analysis of the capacity curves, an improved redox activity of V5+ was strongly demonstrated. Moreover, compared to the basic materials, an increasing rate capacity located in the low potential range was detected, ascribed to the existence of an oxygen vacancy, enabling a reduction in the energy barrier and a broadening of the energy distribution. Interestingly, La-doping could ultimately improve the capacity and is thus worth further exploration, particularly for the design of advanced cathodic materials.

The superposition state of photonic orbital angular momentum (OAM) has more degrees of freedom than pure photonic orbital angular momentum, with rich physical implications and engineering application possibilities. Here we propose a scheme for polarization multiplexed terahertz OAM superposition state generation using an all-silicon metasurface. Two types of spatially interlaced metasurface OAM superposition state generators are designed and experimentally verified, which realize the generation of polarization-dependent single or multiple terahertz vortex interference beams. The first type of metasurface consists of polarization-maintaining silicon pillar arrays, which can switch the transmitted terahertz beam between different OAM superposition states. The analyzer direction of the superposition state is always consistent with the incident polarization. The second type of metasurface introduces units with a polarization conversion function, so that the analyzer direction of the OAM superposition state under different incident polarizations is always kept unchanged. In addition, the proposed metasurfaces can also generate a longitudinal electric field component and manipulate the superposition state of OAM. Both types of metasurfaces show excellent performance of efficient generation and switching of terahertz OAM superposition states. This method provides a new idea for photonic OAM manipulation based on metasurfaces.

GeTe has become a high-performance thermoelectric material with a figure of merit (ZT) over two through alloying and band engineering strategies. Yet, the question on how to effectively engineer the electronic band structure of GeTe toward achieving a better thermoelectric performance still cannot be clearly answered, and its underlying physics has not been well understood. Here, we manipulate the lattice structure of GeTe via modifying the lattice parameters, interaxial angles and reciprocal displacements, and investigate their influence on the electronic band structure and thermoelectric properties using first-principles calculations. The calculation results show that the reciprocal displacement directly manipulates the energy level of the L-band and the Z-band, resulting in an indirect–direct transition of the band gap and a strong Rashba effect. Modifications of lattice parameters and interaxial angles can affect band gaps, band convergence and density of states, which are crucial to determining thermoelectric performance. This work performs a systematic study on how the lattice structure manipulation influences the electronic band structure and thermoelectric properties of GeTe, and can provide a clear route to further enhance its ZT.

Robust and economical catalysts are imperative to realize the versatile applications of hydrogen. Herein, a 1T-MoS2/N-doped NiSe2 composite was rationally synthesized via a solvothermal method, in which the MoS2 nanosheets have a stable 1T phase structure, and the NiSe2 nanoparticles serve as a cocatalytic support for MoS2. The nonnegligible electronic couplings between NiSe2 and MoS2 could facilitate the optimization of their electronic structure and then improve the hydrogen adsorption. What is more, the nitrogen dopants in the NiSe2 nanoparticles could intensify the intercalation of ammonium ions in the 1T-MoS2 nanosheets, and further enlarge their interlayer spacing, thus the electrolyte could infiltrate into the catalyst more easily and sufficiently. This work provides a new route for rationally designing highly active and low cost hydrogen evolution reaction (HER) catalysts, and enriches the study of transition metal chalcogenides toward HER.

Monoacetin was synthesized using a novel green method in which acetonitrile was hydrolyzed and then esterified with glycerol over Cu-Cr phosphates under the CO2 atmosphere. Monoacetin was synthesized with high yield (87.6% glycerol conversion and 86.3% monoacetin selectivity) through this one-pot cascade method. In this process, acetonitrile can react with water to form acetamide and further undergo esterification with glycerol. There are two main reasons for obtaining monoacetin in high yield: (1) the interaction of CO2 with high-temperature liquid water enhances the acid strength of the reaction system and then promotes the activation of acetonitrile; and (2) the introduction of Cr species causes a synergistic effect between Cu and Cr species to adjust the acidity and basicity of the catalyst. The introduction of Cr species converts eight-coordinated Cu2+ into four-coordinated Cu2+ to improve the acidity of the catalyst. The introduction of Cr species also causes the surface oxygen to be transformed into lattice oxygen to enhance the basicity of the catalyst. These bimetallic phosphate materials may provide a new pathway for the application of acid-base bifunctional catalytic reactions.

Magnetic Ni0.5Zn0.5Fe2O4/ZnO-R (NZFO/ZnO-R) nanocomposites are prepared via the rapid combustion-coprecipitation process, and they are characterized by the Fourier Transform Infrared Spectroscopy (FTIR), the X-ray Diffraction (XRD), the Scanning Electron Microscopy (SEM), the Energy Dispersive X-ray Detector (EDX), the Specific Surface Area (BET), the UV-vis Diffuse Reflection Spectroscopy (DRS), and the Vibrating Sample Magnetometer (VSM). The photocatalytic activity of NZFO/ZnO-R nanocomposites is assessed in ultraviolet light (365 nm) by decoloration of methylene blue (MB). The results show that the magnetic NZFO/ZnO-0.2 nanocomposites consist of particles and rods. The size of particles is 18 nm. The width and length of rods are 66 nm and 198 nm, respectively. NZFO/ZnO-0.5 nanocomposites have better photocatalytic performance than that of NZFO, ZnO and NZFO/ZnO-R (R = 0.2, 0.3, 0.4, 0.6, or 0.7) from the results. Through careful investigation of influencing parameters (the amount of catalysts, pH and concentration of MB solution), the degradation efficiency of MB is closely connected with the transparency of solution and surface charge of catalysts. The enhanced photocatalytic activity of NZFO/ZnO-0.5 nanocomposites can be ascribed to the matching band positions between ZnO and NZFO, which results in a low recombination between the photogenerated electron-hole pairs. The possible mechanism is proposed for the improved ultraviolet photocatalytic activity of NZFO/ZnO-0.5 nanocomposites.

Integrating stretchability, self-healability, and surface adhesive properties in a single material is attractive for expanding the applications in demanding fields. Herein, we have studied the meta...

The trivalent europium ion (Eu3+) has garnered a great deal of interest for the design of luminescent materials possessing compound-independent emission bands, strong luminescent intensity, and long emission lifetimes. We herein introduce a synthetic methodology capable of constructing visual luminescent probes from Eu3+ complex-functionalized silica nanocomposites and their Langmuir-Blodgett (LB) films at interfaces. In order to facilitate the coordinative stabilization of Eu3+ over carrier surfaces, silica nanoparticles (nanoSiO2) were pregrafted with terpyridyl (TPy) to make nanoSiO2TPy linkers. Then, a well-designed coordination reaction of nanoSiO2TPy with EuCl3 and 2,6-pyridinedicarboxylic acid (DPA) was carried out at solid-liquid and air-water interfaces, where our desired material (denoted as nanoSiO2TPy@EuDPA) and its corresponding LB film are obtained. The presence of TPy and DPA interacting with Eu3+ plays a key role in regulating the chemical nature of the particle surface, hence giving rise to closely packed nanocomposite arrays in the film. As a result, the improvement in uniformity and stability is achieved alongside the enhancement in emission intensity and lifetime. With such advantageous optical properties, we find them workable as facile, green, and affordable luminescent sensors, by which a range of common toxic anions (Cr2O72-, MnO4-, and PO43-) can be visually and quantitatively recognized. Notably, the LB film-based material could afford a higher Ksv value (1.53 × 105 M-1), a lower detection limit (0.157 µM), and better recyclability than its original powder analogue, showcasing its utility as a more promising candidate for practical use.

Fumed silica (FS)-filled polydimethylsiloxane (PDMS) composite is widely used as the external insulating material in power grid. The function of PDMS composite is to keep the core of an insulation device being dry by preventing the permeation of outside water. To study water diffusion in PDMS composite helps to shed light upon the failure mechanism of the insulation devices. In this paper, positron annihilation lifetime spectroscopy (PALS) and electrochemical impedance spectroscopy (EIS) were applied to study the FS/PDMS interface structure and water diffusion in PDMS composite. It is found that the FS has two basic existing states in PDMS matrix: dispersed state and percolated state, and the percolation threshold of FS is fitted to be 6.0 wt.%. In the dispersed state, the FS particles are randomly dispersed in PDMS matrix. The values of $$\tau _3$$ remain stable, being approximately 1.0 ns, indicating no overlaps of the FS/PDMS interfaces. Moreover, water cannot diffuse through the sample after corona aging. In the percolated state, the FS particles are tightly packed in the PDMS matrix. The values of $$\tau _3$$ decrease with the weight fraction of FS, suggesting the overlapping of the FS/PDMS interfaces. As the FS percolates in sample bulk, these overlapped FS/PDMS interfaces provide continuous diffusion tunnels for water, thus resulting in failure of the composite after corona aging. It is found that polarization and discharge of the electrons at FS/PDMS interface under corona discharge is the main mechanism that leads to the failure of the composite bulk.

C2H4/N2O has recently been proposed as a promising monopropellant for hydrazine replacement. In this work, the auto-ignition capability of argon diluted C2H4/N2O was experimentally investigated firstly in a rapid compression machine by detecting the light emission and the pressure evolution profiles. The auto-ignition boundary temperature which separates the non-ignition and successful ignition cases was then determined and modeled as a function of pressure and mixture composition. Results show that the auto-ignition temperature decreases with the increase of pressure and increases with the argon dilution fraction and fuel oxidizer ratio. In addition, for successful auto-ignition cases, the ignition delay times were measured and used to validate several recently developed kinetic mechanisms. A mechanism was developed and showed good agreement with the measured ignition delay time as well as the auto-ignition boundary temperature at all test conditions. Finally, the auto-ignition boundary temperatures at practical rocket engine conditions (without dilution) were numerically predicted at various pressure and fuel oxidizer ratio conditions. The model is of merit for designing the cooling system and the local flow residence time to reduce the risk of fuel line explosion and the resonance acoustic induced combustion instability in practical rocket engine.

The oil soluble modified montmorillonite (MMT)/indium (In) composite nanoscale powders were prepared into four disperse systems by adding 1%, 2%, 3% and 4% to the base oil respectively. The friction properties of the 45 steel samples were tested by MMU-10G friction and wear testing machine, and the surface composition of the samples was analyzed by SEM and EDX. The mechanism that affects the tribological properties is compared and analyzed. The results show that the wear weight loss of the sample added with MMT/In nano powder is smaller than that in the base oil, and the average friction factor of the sample with 3% additions is 43.14% ,lower than that of the base oil, and the total wear is negative weightlessness.EDX analysis showed that the surface of the friction specimen was composed of Mg, Al and In repair membranes. The main mechanism of anti friction and friction reduction is that the composite powder will form a repair film on the surface of the friction pair during the friction process, and the repair layer can reduce the friction, compensate for the wear and play the role of resisting wear and reducing the effect of friction. With the increase of adding amount, the repair layer is gradually improved and the tribological performance is enhanced. But if the amount of addition is too high, the micro cutting and furrow effect of a large number of hard particles on the matrix and the new film will be greater than the compensation effect of the repair film, making the antiwear and antifriction properties decrease.

Alkaline anion exchange membrane fuel cells (AEMFCs) are attracting more and more attention due to the advantages of using non-platinum-group (NPG) metal catalysts and less expensive metal hardware at the high pH conditions. However, the studies of electrodes with the non-precious metal are still less and the performance of the AEMFC operated with the NPG metal catalysts need to improve. In this work, based on AEMFCs operated with the commercial non-precious metal ORR catalysts (Acta 4020), a two dimensional, two-phase flow and steady-state agglomerates model is developed, and the effects of operational conditions of the relative humidity and the structure of the catalyst layer on fuel cell performance are numerically studied and analyzed. The results demonstrate that the relative humidity directly impacts the water distribution and transport in the MEA, and the low relative humidity in the cathode can increase the water back diffusion from the anode to the cathode and improve the fuel cell performance. An increase in the catalyst loading has been found to have a positive effects on the fuel cell performance, but the improvement is limited when the catalyst loading increases to a certain value. In addition, the increase in the mass ratio of catalyst to ionomer results in a decrease in the thickness of the ionomer film, but the excessive mass ratio of the catalyst to the ionomer also leads to a decrease in ionic conductivity, thereby deteriorating the performance of fuel cell. At last, operating with the optimized conditions from the model, the AEMFC realized a good fuel cell performance, and the peak power density reached 566 mW cm−2 and 326 mW cm−2 for H2/O2 and H2/Air (CO2-free) at 60 °C, respectively, and the results are higher than those reported in references.

MnO2 has the highest potential as a supercapacitor electrode; however, its disadvantage in electronic conductivity hinders its widespread use. This study reports the excellent electrochemical performance of MnMC/NF (MnO2 and ZIF-derived nanoporous carbon on nickel foam) composites. MnMC/NF composites are produced when leaf-like Co-ZIF is annealed on nickel foam, followed by potassium permanganate treatment. When the annealing temperature reaches 700 °C, the maximum specific capacitance of 531 F/g is achieved at 1 A/g (456 F/g at 20 A/g) with a rate capability of 85.5%. MnMC/NF700 has a long cyclic stability, and the capacitance retention was 82% after 5000 cycles. The energy density of an assembled device using MnMC/NF700 composite as positive electrodes can reach 38.8 Wh/kg. This is due to the combined effect of nickel substrate's 3D porous structure and the excellent electronic conductivity of ZIF-derived nanoporous carbon. The unique configuration of MnMC/NF composites may provide a referable design for energy storage systems, including materials that have the highest potential for use as supercapacitor electrodes.

Water management has been proven significant for enhancing both performance and durability of anion exchange membrane fuel cell. Besides searching new material, decreasing membrane thickness and modifying operation parameters, a simple and universal method of altering membrane structure is proposed in this work. Composite membranes made by unique processing method that includes both casting and electrospinning processes were compared with traditional casting membrane, all with the same thickness of 40 µm. Comparing to traditional casting membrane, the composite membrane put at proper position shows a higher water permeability, thus even more than 50% enhancement of the peak performance.

Prosthesis-associated infections and aseptic loosening are major causes of implant failure. There is an urgent need to improve the antibacterial ability and osseointegration of orthopedic implants. Zinc oxide nanoparticles (ZnO-NPs) are a common type of zinc-containing metal oxide nanoparticles that have been widely studied in many fields, such as food packaging, pollution treatment, and biomedicine. The ZnO-NPs have low toxicity and good biological functions, as well as antibacterial, anticancer, and osteogenic capabilities. Furthermore, ZnO-NPs can be easily obtained through various methods. Among them, green preparation methods can improve the bioactivity of ZnO-NPs and strengthen their potential application in the biological field. This review discusses the antibacterial abilities of ZnO-NPs, including mechanisms and influencing factors. The toxicity and shortcomings of anticancer applications are summarized. Furthermore, osteogenic mechanisms and synergy with other materials are introduced. Green preparation methods are also briefly reviewed.

Chiral metasurfaces can achieve giant chiral optical responses and have been expanded from the optical band to other electromagnetic bands. Here, we propose a new method for dynamic terahertz circular dichroism (CD) manipulation in metasurfaces. By introducing a patterned and electrically doped graphene into the metamirror consists of double layer C-shaped split ring resonators (SRRs), efficient terahertz CD modulation is observed. Since the electrical doping of graphene changes the absorption loss of the metasuface cavity, the structure shows switching between a chiral metasurface and an ordinary metal mirror, which can be seen as "on" and "off" states. The calculation results show an efficient modulation of the terahertz CD in a large dynamic range. In addition, we also use the new method to design two metasurfaces for dynamic terahertz wavefront modulation and near-field digital imaging, both of which show a high-performance electrical switching. This method provides a new way for the design of active terahertz devices based on metasurfaces, and also promotes the applications of terahertz chiral metasurfaces in high-speed wireless communication and dynamic imaging.

In this study, sheet bulk metal forming (SBMF) processes for manufacturing sidewall-thickened cups were explored, including sheet forming processes for the preparation of cup billets and bulk forming processes for sidewall thickening. To avoid forging laps caused by the clearance between the cup corner and die during sidewall upsetting, a locally thickened tailored blank was designed and produced. To form tailored blanks, coining and orbital forming were compared, and a strategy based on a coining process with different lubrication conditions was analyzed. The tailored blanks were drawn to cups, which had sharp corners and were used as billets for the final upsetting operation to avoid the clearance and thus eliminate forging laps. Adopting upsetting with controllable deformation zone (U-CDZ) method, the cup sidewall was thickened. During forming, the buckling on the sidewall and laps on the corner were prevented. The numerical and experimental results indicate that sheet parts with complex sections can be formed using a tailored blank with the U-CDZ method.

The lithium (Li)-air battery has an ultrahigh theoretical specific energy, however, even in pure oxygen (O2 ), the vulnerability of conventional organic electrolytes and carbon cathodes towards reaction intermediates, especially O2 - , and corrosive oxidation and crack/pulverization of Li metal anode lead to poor cycling stability of the Li-air battery. Even worse, the water and/or CO2 in air bring parasitic reactions and safety issues. Therefore, applying such systems in open-air environment is challenging. Herein, contrary to previous assertions, we have found that CO2 can improve the stability of both anode and electrolyte, and a high-performance rechargeable Li-O2 /CO2 battery is developed. The CO2 not only facilitates the in situ formation of a passivated protective Li2 CO3 film on the Li anode, but also restrains side reactions involving electrolyte and cathode by capturing O2 - . Moreover, the Pd/CNT catalyst in the cathode can extend the battery lifespan by effectively tuning the product morphology and catalyzing the decomposition of Li2 CO3 . The Li-O2 /CO2 battery achieves a full discharge capacity of 6628 mAh g-1 and a long life of 715 cycles, which is even better than those of pure Li-O2 batteries.

From the perspective of resource reserves, environmental effects, and production costs, direct utilization of natural ores as electrode materials for rechargeable batteries after mineral processing is of more practical significance than chemosynthetic materials. While the corresponding investigation is relatively insufficient, herein phenolic resin (PR)-coated natural pyrite composite (FeS₂@PR) is successfully fabricated using natural pyrite and oligomeric phenolic resin as starting materials. Subsequent oligomer polymerization and calcination process convert FeS₂@C into sulfur-doped carbon-coated Fe₇S₈ (FS@C). Benefiting from the good electric and ionic conductivity of Fe₇S₈, abundant sulfur active sites, and porosity on carbon shell and effective carbon buffering, FS@C exhibits impressive electrochemical performance as anodes for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). It delivers high reversible capacities of 1319 and 796 mAh g–¹ after 100 cycles at 0.1 A g–¹ for LIBs and SIBs, respectively. Even at a high current density of 2.0 A g–¹, considerable capacities of 771 mAh g–¹ after 1000 cycles and 545 mAh g–¹ after 400 cycles are retained for LIBs and SIBs. This work provides a promising prospect toward scalable production of high-capacity iron sulfide anode for lithium-ion and sodium-ion batteries.

A novel sandwich-type electrochemical immunosensor based on cuprous oxide (Cu2O)@copper-metal organic framework (Cu-MOF)@gold nanoparticles (Au NPs) core–shell structure was proposed. Cu2O@Cu-MOF@Au attached with horseradish peroxidase (HRP) triple-catalyzed hydrogen peroxide (H2O2) for detecting CEA antigen. In this work, 50 nm Cu2O nanospheres were prepared. Using Cu2O nanospheres as the core, Cu-MOF was coated on the surface of Cu2O nanospheres by reaction of Cu2O and ligands. Subsequently, chloroauric acid was reduced to Au NPs without adding any reducing agent and Au NPs dispersed on the surface of Cu-MOF. Finally, the Cu2O@Cu-MOF@Au-HRP-Ab2 nanoprobe was successfully prepared. Immunosensors had good performance due to the following reasons. Firstly, Cu2O, Cu-MOF and HRP have excellent catalytic properties for hydrogen peroxide. In addition, the synergistic effect of Cu2O, Cu-MOF and HRP promoted the reduction of hydrogen peroxide and tripled amplification of electrical signals. Here, the successfully prepared immunosensor detected carcinoembryonic antigen (CEA) sensitively, the detection range was 50 fg/mL–80 ng/mL, and the detection limit was 17 fg/mL. Besides, the proposed immunosensor had good stability, selectivity and specificity. Detection in human serum samples had good results without matrix effect. This provided a new idea for the clinical detection of tumor markers: "metal oxide—metal organic framework—precious metal nanoparticles" (MMP).

The high-temperature (up to 200 °C) reliability analysis of 1200V/100A 4H-SiC JBS under 168 hours of high-temperature storage stress (HTSS), high-temperature reverse bias (HTRB) and high-humidity HTRB (H3TRB) stress test are reported. Results show that, all the statistical distribution of the data consistency is more dispersed after HTSS, HTRB and H3TRB test, which suggests that there are more degradation in the forward voltage and leakage current characteristics of JBS device under high temperature (up to 423K) stress. The increased reverse leakage currents after HTSS and HTRB stresses at different test temperatures are mainly due to the thermionic emission with the image force barrier height lowering. However, it is not the same phenomenon after HTRB stress. And the stability of VR under HTRB test is better than the one under HTSS test, which may be due to the migration and accumulation of charge during exposure to HTRB.