High Performance Stability Research Articles

Polyfunctional Arylamine Based Nanofiltration Membranes with Enhanced Aggressive Organic Solvents Resistance.

Organic solvent nanofiltration (OSN) membranes with high separation performance and excellent stability in aggressive organic solvents are urgently desired for chemical separation. Herein, we utilized a polyfunctional arylamine tetra-(4-aminophenyl) ethylene (TAPE) to prepare a highly cross-linked polyamide membrane with a low molecular weight cut-off (MWCO) of 312 Da. Owing to its propeller-like conformation, TAPE formed micropores within the polyamide membrane and provided fast solvent transport channels. Importantly, the rigid conjugated skeleton and high connectivity between micropores effectively prevented the expansion of the polyamide matrix in aggressive organic solvents. The membrane maintained high separation performance even immersed in N,N-dimethylformamide for 90 days. Based on the aggregation-induced emission (AIE) effect of TAPE, the formation of polyamide membrane can be visually monitored by fluorescence imaging technology, which achieved visual guidance for membrane fabrication. This work provides a vital foundation for utilizing polyfunctional monomers in the interfacial polymerization reaction to prepare high-performance OSN membranes.

Mechanical and microstructure characterisation of 2.5D C/C-SiC composites applied for the brake disc of high-speed train

Carbon fibre reinforced silicon carbide (C/C-SiC) composite materials have attracted increasing attention in brake system of high-speed trains, due to their low density, high specific strength, thermal stability, and frictional wear performance. This study aims to explore the mechanical properties of the 2.5D C/C-SiC composites, in order to characterise its potential application to the friction braking system of high-speed trains. To comprehensively evaluate the mechanical performance of the 2.5D C/C-SiC composites, the chemical vapor infiltration (CVI) method was adopted to prepare novel samples with high densification and low content of residual Si. The mechanical properties and failure mechanisms of the composites were investigated under various loading conditions, including tension, compression, bending, and shear tests. The experimental results indicated that the 2.5D C/C-SiC composites exhibited superior mechanical properties, with average in-plane tensile strength, compressive strength, bending strength, and interlaminar shear strength reaching 127.67 MPa, 326.92 MPa, 355.74 MPa, and 9.77 MPa, respectively, which are 2–8 times higher than the mechanical properties of C/C-SiC composites in existing publications. Under different loading conditions, the composites demonstrated characteristics of ductile fracture, pseudo-plastic compression fracture, pseudo-plastic bending fracture, and brittle shear fracture. Both high fibre content and the formation of SiC structure were advantageous for enhancing the load-bearing performance of C/C-SiC composites. The outstanding mechanical properties of the 2.5D C/C-SiC composite render the brake disc highly resistant to deformation and cracking under high stress, thereby enhancing its durability and establishing it as the ideal material for the next generation of high-speed train brake discs.

Stable and efficient all-inorganic quantum dot light-emitting diodes based on a double-layer electron transport layer

Abstract The most advanced quantum light-emitting diodes (QLEDs) have achieved almost unity external quantum efficiency (EQE) due to organic materials for high transport efficiency, but organic materials are less stable and can lead to irreversible degradation of the devices. The use of stable inorganic hole-transporting layers (HTLs), such as NiOx, becomes a promising alternative. ZnO is a common electron-transporting material in QLEDs, which possesses high mobility and tunable conductivity properties, but ZnO-based QLEDs devices undergo loss of efficiency due to exciton bursting, poor shelf stability, and pronounced positive aging effects. SnO2, as a common electron-transporting material, has better stability than ZnO. In this work, the SnO2/ZnO dual electron transport layer strategy is adopted, which can reduce the non-radiative burst and aging behavior, and at the same time, the electron transport is regulated by adjusting the film thickness. Inorganic QLEDs with high external quantum efficiency (9.5%) as well as high operational stability have been fully realized. This strategy provides effective ideas for future high-performance display devices.

New hole transport materials based on polybenzo[1,2-b:4,5-b']dithiophene polymers with different side chains for n-i-p perovskite solar cells

A series of new homo- and copolymers P1–P6 with the main chains comprised exclusively of benzo [1,2-b:4,5-b']dithiophene units were synthesized using Stille polycondensation reaction. The optical and electrochemical properties of P1–P6 polymers were studied to estimate the frontier orbitals energies and the Eg values. The obtained data demonstrate the possibility of controlling the electronic properties of polybenzo [1,2-b:4,5-b']dithiophenes by varying only the structure and combinations of solubilizing alkyl side chains. The polymers P1–P6 were evaluated as hole transport materials in n-i-p perovskite solar cells. The highest efficiency of 18.6 % was delivered by the cells with one of the designed polymers with an optimal combination of alternating mono- and dialkylthiophene substituents. The high photovoltaic performance and decent operational stability were achieved using polymer films without any doping, which paves a way to design of inexpensive and scalable dopant-free materials for perovskite solar cells.

NiOx Passivation in Perovskite Solar Cells: From Surface Reactivity to Device Performance.

Nonstoichiometric nickel oxide (NiOx) is one of the very few metal oxides successfully used as hole extraction layer in p-i-n type perovskite solar cells (PSCs). Its favorable optoelectronic properties and facile large-scale preparation methods are potentially relevant for future commercialization of PSCs, though currently low operational stability of PSCs is reported when a NiOx hole extraction layer is used in direct contact with the perovskite absorber. Poorly understood degradation reactions at this interface are seen as cause for the inferior stability, and a variety of interface passivation approaches have been shown to be effective in improving the overall solar cell performance. To gain a better understanding of the processes happening at this interface, we systematically passivated specific defects on NiOx with three different categories of organic/inorganic compounds. The effects on NiOx and the perovskite (MAPbI3) deposited on top were investigated using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Here, we find that the perovskite's structural stability and film formation can be significantly affected by the passivation treatment of the NiOx surface. In combination with density functional theory (DFT) calculations, a likely origin of NiOx-perovskite degradation interactions is proposed. The surface passivated NiOx layers were incorporated into MAPbI3-based PSCs, and the influence on device performance and operational stability was investigated by current-voltage (J-V) characterization, impedance spectroscopy (IS), and open circuit voltage decay (OCVD) measurements. Interestingly, we find that a superior structural stability due to interface passivation must not relate to high operational stability. The discrepancy comes from the formation of excess ions at the interface, which negatively impacts all solar cell parameters.

The synthesis of hollow carbon nanospheres from potato starch and the application in supercapacitor

The synthesis of high-valued carbon nanomaterials from biomass has always been a hot topic. The work reports the preparation of hollow carbon nanospheres (HCNs) from potato starch with one-step carbonization, in which self-made MgO powder is utilized as the template. In this study, an attempt was made to change carbonization temperature to control HCNs in diameter, wall thickness and pore distribution. Results show that the sample obtained at 800 °C (HCN-800) has a thinner wall thickness (about 12.1 nm), smaller and more uniform diameter (average diameter of 46.2 nm), as well as possesses a high specific surface area (619.53 m2 g−1) and the largest pore volume (2.8994 cm3 g−1). An application in supercapacitor has been verified for the HCNs in the work. In the three-electrode system, the HCN-800 exhibits excellent electrochemical performance, such as superior specific capacitance (324.8 F g−1 at 0.5 A g−1), high rate performance (215.7 F g−1 at 50 A g−1) and outstanding cycling stability (92.83 % capacitance retention after 10,000 cycles). Moreover, an assembled symmetric supercapacitor shows an energy density of 11.1 Wh kg−1 at a power density of 427 W kg−1, far exceeding that of previously reported carbon electrode materials. In short, the work provides a novel way to synthesize high-value-added HCNs from cheap biomass precursors, which have potential applications in the field of supercapacitors and other energy storage devices.

Nucleobase-modulated copper nanomaterials with laccase-like activity for high-performance degradation and detection of phenolic pollutants

Laccases are the most commonly used agents for the treatment of phenolic pollutants. To address the instability and high cost of natural laccases, we investigated nucleobase-modulated copper nanomaterial with laccase-like activity. Various nucleobases, including adenine, guanine, cytosine, and thymine, were investigated as templates for Cu2+ reduction and copper nanomaterials formation due to their coordination capacity. By comparing structure and catalytic activity, the cytosine-mediated copper nanomaterial (C–Cu) had the best laccase-like activity and other nucleobase-templated copper nanomaterials exhibited low catalytic activity under the same conditions. The mechanism of nucleobase regulation of the catalytic activity of copper nanomaterials was further analyzed using X-ray photoelectron spectroscopy and density functional theory. The possible catalytic mechanisms of C–Cu, including substrate adsorption, substrate oxidation, oxygen binding, and oxygen reduction, were proposed. Remarkably, nucleobase-modulated copper nanozymes showed high stability and catalytic oxidation performance at various pH values, temperatures, long-term storage, and high salinity. In combination with electrochemical techniques, a portable electrochemical sensor for measuring phenolic pollutants was developed. This novel sensor exhibited a good linear response to catechol (10–1000 μM) with a limit of detection of 1.8 μM and excellent selectivity and anti-interference ability. This study provides not only a new strategy for the regulation of the laccase-like activity of copper nanomaterials but also a novel tool for the effective removal and low-cost detection of phenolic pollutants.

Zwitterion‐Separated Ion Pair Dominated Additive‐Electrolyte Structure for Ultra‐Stable Aqueous Zinc Ion Batteries

AbstractAqueous zinc ion batteries (AZIBs) are promising for large‐scale energy storage due to the advantages of high safety, high theoretical capacity, and cost‐effectiveness. However, the stability of AZIBs is poor (generally 50–100 cycles) at low current densities due to side reactions. Here, choline glycerophosphate (CGP) is introduced as a zwitterion additive to improve performance of AZIBs. The CGP helps to form a new solvated structure of Zn2+, named zwitterion‐separated ion pair (ZSIP) structure that can link OTf− ion and repel H2O molecular. In addition, CGP can be adsorbed on anode to suppress formation of by‐products ZnxOTfy(OH)2x‐y·nH2O, and on cathode to inhibit Zn3(OH)2V2O7·2H2O phase generation. Consequently, the Zn||Cu cell shows an excellent average Coulombic efficiency of 99.79% over 800 cycles at 1 mA cm−2 and 0.5 mAh cm−2. Impressively, the Zn//NH4V4O10 battery demonstrates exceptional capacity retention of 95% along with a high specific capacity of 409.3 mAh g−1 after 350 cycles under a trickle (dis)charge process (0.2 A g−1) and an ultra‐long lifespan of 14 000 cycles at 5 A g−1 along with a high specific capacity of 217 mAh g−1. The concept of ZSIP opens a new avenue for developing aqueous batteries with high performance and long stability in the future.

Mechanochemically synthesized RuO2‐doped LaMnO3 perovskites as bifunctional cathodes for rechargeable Zn/air batteries

Herein, we have developed LaMnO3 (LMO) perovskite‐based electrocatalysts of oxygen reduction and oxygen evolution reactions (ORR and OER) in a basic aqueous solution. Mechanochemical grinding and thermal annealing leads to highly‐pure perovskites as shown by X‐ray diffraction. This methodology allows as well for a swift integration of RuO2 additive which improves especially the oxygen evolution reaction. ORR have been analyzed by rotating ring‐disk electrode (RRDE). Eventually, these catalysts are employed in Zn/air batteries resulting in specific capacity values of 12.76 Ahg‐1 at 1 Ag‐1, when LMO‐RuO2 (LMO‐Ru) was used as catalyst in the positive electrodes. Besides, high operational stability of Zn/air batteries for over 100 cycles was obtained, saving 1,46 mWh per cycle when LMO‐Ru was used with respect to pure LMO.

High luminous efficiency and Ultra-Stable CsPbBr3@CsPb2Br5:Sr core-shell microplate for white light emitting diodes

CsPbX3 (X = Br, Cl, and I) perovskite quantum dots (QDs) have become promising materials for phosphors and solar cells due to their remarkable photovoltaic properties. However, the high defect density and sensitivity to the surrounding environment have hindered the commercial application of the materials in the field of optoelectronics. Core-shell structures have been proved to be an effective method for passivating surface defects and improving stability. However, the complex post-processing tends to dissolve the CsPbX3 QDs, causing the strategy to remain relatively underdeveloped. Here, we present an improved hot-injection method that can facilitate the epitaxial growth of CsPb2Br5 shell on the surface of CsPbBr3 QDs, and, by doping Sr2+ ions to passivate the defects of the QDs, CsPbBr3@CsPb2Br5:Sr core-shell microplates have been obtained. The composites have enhanced optical properties and stability. Density Functional Theory (DFT) calculations show that this is benefited from the introduction of Sr which widens the bandgap of CsPbBr3 and CsPb2Br5, leading to the formation of a quantum well structure between the two, significantly improving the quantum yields of the samples. Finally, the white light emitting diodes prepared using the composite have high luminous efficiency and long-term operational stability.

Off-Stoichiometry of Sodium Iron Pyrophosphate as Cathode Materials for Sodium-Ion Batteries with Superior Cycling Stability.

As one of the important devices for large-scale electrochemical energy storage, sodium-ion batteries have received much attention due to the abundant resources of raw materials. However, whether it is a base station power source, an energy storage power station, or a start-stop power supply, long energy cycle life (more than 5000 cycles), high stability, and safety performance are application prerequisites. Regrettably, currently, few sodium-ion batteries can meet this requirement, mainly due to shortcomings in positive electrode performance. We report a sufficiently stable sodium-ion battery cathode material, Na2Fe0.95P2O7, that retains 97.5% capacity after 5000 charge/discharge cycles. The use of nonstoichiometry in the lattice enables simultaneous modification of the crystal and electronic structure, promoting Na2Fe0.95P2O7 to be extremely stable while still being able to achieve a capacity of 92 mAh g-1 and stable cycling at high temperatures up to 60 °C. Our results confirm the positive effect of nonstoichiometric ratios on the performance of Na2Fe0.95P2O7 and provide a reliable idea to promote the practical application of sodium-ion batteries.

Photothermal Effect of Cu NCs on CdS Homojunction Boosting Hydrogen Evolution in Alkaline Seawater

AbstractDeveloping photocatalysts with desired activity and stability toward hydrogen evolution reaction (HER) in alkaline seawater is of prime significance but still pressingly challenging. Herein, cuprum nanoclusters (CuNCs) are anchored on the surface of cadmium sulphide homojunctions (CdS‐H) with unsaturated edge sulphur (S) by an in situ photoreduction technique, which promotes the stability and hydrogen evolution of photocatalyst in the process of alkaline seawater hydrogen (H2) evolution (15.5 mmol g−1 h−1) with an apparent quantum yield of 11.0% at 450.0 nm. It is comprehensively confirmed that the unsaturated edge S not only effectively anchored Cu NCs but also promoted the adsorption of chloride ion (Cl−) ions, which suppressed the oxidation of lattice S and modulated the stability of the photocatalyst in alkaline seawater. The photothermal effect induced by the anchored Cu NCs accelerated the reaction kinetics, and the directional migration of the photocarrier at the metal‐semiconductor interface is demonstrated via the in situ method. This work affords a new perspective to rational design photocatalysts with high stability and superior performance in alkaline seawater.

Coordination engineering of defective F and N co-doped carbon dots anchored silver nanoparticles for boosting oxygen reduction reaction

The carbon-based catalysts exhibit excellent electrocatalytic and stable performance toward oxygen reduction reaction (ORR), which are expected to replace expensive and scarce Pt-based catalysts. However, how to regulate the interaction between silver and carrier carbon dots (CD) to improve electrocatalytic performance toward oxygen reduction reaction (ORR) and stability, has not been systematically studied. In this study, we in-situ synthesized fluorine and nitrogen co-doped CD anchoring Ag nanoparticles by UV irradiation reduction method. The peak potential, onset-potential and half-wave potential of F, N-CD@Ag-0.1 are 0.85 V, 1.056 V, and 0.9 V, respectively, indicating outstanding ORR performance. The current density of F, N-CD@Ag-0.1 remains 97.5 % after 50, 000 s, showing more excellent stability than Pt/C. The impressive ORR catalytic activity and stability of F, N-CD@Ag-0.1 could be attributed to the strong anchoring effect of nitrogen-doped CD on Ag. This effect leads to a significant interaction and charge transfer between Ag and CD, thereby enhancing the charge transfer process during the catalytic reaction. This project aims to design a carbon dot/silver composite catalyst with high ORR catalytic performance and favorable stability. The implementation of this project provides good theoretical guidance for the design of carbon nanomaterial-based catalytic systems.

Combination of 1,2,4-Oxadiazolone and Pyrazole for the Generation of Energetic Materials with Relatively High Detonation Performance and Good Thermal Stability

Combination of 1,2,4-Oxadiazolone and Pyrazole for the Generation of Energetic Materials with Relatively High Detonation Performance and Good Thermal Stability

Super-flexible and low-shrinkage polyimide aerogel composites with excellent thermal insulation: Boosted by SiO2 micron aerogel powder

Polyimide (PI) aerogel composites were synthesized using 4,4′-diaminodiphenyl ether (ODA) and 1,3-bis(4-aminophenoxy)neopentane (BAPN) as diamine monomers, and biphenyl-3,3′,4,4′-tetracarboxylic dianhydride (BPDA) as dianhydride monomers. This study examined the impact of varying proportions of SiO2 micron aerogel powder and the addition of BTC on the properties of the composites. The prepared composites showed ultra-high flexibility (180° folded) with the thickness of 3–4 mm, high thermal stability (95 % weight retention at 501 °C) and thermal insulation performance with ultralow thermal conductivity of 0.033 W/(K·m).

Optimizing Nanofluidic Energy Harvesting in Synthetic Clay-based Membranes by Annealing Treatment.

Nanofluidic energy harvesting from salinity gradients is studied in 2D nanomaterials-based membranes with promising performance as high ion selectivity and fast ion transport. In addition, moving forward to scalable, feasible systems requires environmentally friendly materials to make the application sustainable. Clay-based membranes are attractive for being environmentally friendly, non-hazardous, and easy to manipulate materials. However, achieving underwater stability for clay-based membranes remains challenging. In this work, the synthetic clay Laponite is used to prepare clay-based membranes with high stability and excellent performance for osmotic energy harvesting. The Laponite membranes (Lap-membranes) are stabilized by low-temperature annealing treatment to effectively reduce the interlayer space, achieving a continuous operation under salinity gradients. Furthermore, the Lap-membranes conserve integrity while soaking in water for more than one month. The output power density improves from ≈4.97W m-2 on the pristine membrane to ≈9.89W m-2 in the membrane treated 12 h at 300°C from a 30-fold concentration gradient. Especially, It is found that the presence of interlayer water to be favorable for ion transport. Different mechanisms are proposed in the Lap-membranes involved for efficient ion selectivity and the states found with varying annealing temperatures. This work demonstrates the potential application of Laponite based nanomaterials for nanofluidic energy harvesting.

Revisiting porous foam Cu host based Li metal anode: The roles of lithiophilicity and hierarchical structure of three-dimensional framework

Lithium (Li) metal anode (LMA) is one of the most promising anodes for high energy density batteries. However, its practical application is impeded by notorious dendrite growth and huge volume expansion. Although the three-dimensional (3D) host can enhance the cycling stability of LMA, further improvements are still necessary to address the key factors limiting Li plating/stripping behavior. Herein, porous copper (Cu) foam (CF) is thermally infiltrated with molten Li-rich Li-zinc (Li-Zn) binary alloy (CFLZ) with variable Li/Zn atomic ratio. In this process, the LiZn intermetallic compound phase self-assembles into a network of mixed electron/ion conductors that are distributed within the metallic Li phase matrix and this network acts as a sublevel skeleton architecture in the pores of CF, providing a more efficient and structured framework for the material. The as-prepared CFLZ composite anodes are systematically investigated to emphasize the roles of the tunable lithiophilicity and hierarchical structure of the frameworks. Meanwhile, a thin layer of Cu-Zn alloy with strong lithiophilicity covers the CF scaffold itself. The CFLZ with high Zn content facilitates uniform Li nucleation and deposition, thereby effectively suppressing Li dendrite growth and volume fluctuation. Consequently, the hierarchical and lithiophilic framework shows low Li nucleation overpotential and highly stable Coulombic efficiency (CE) for 200 cycles in conventional carbonate based electrolyte. The full cell coupled with LiFePO4 (LFP) cathode demonstrates high cycle stability and rate performance. This work provides valuable insights into the design of advanced dendrite-free 3D LMA toward practical application.

Electrolyte‐gated organic field‐effect transistors with high operational stability and lifetime in practical electrolytes

AbstractA key component of organic bioelectronics is electrolyte‐gated organic field‐effect transistors (EG‐OFETs), which have recently been used as sensors to demonstrate label‐free, single‐molecule detection. However, these devices exhibit limited stability when operated in direct contact with aqueous electrolytes. Ultrahigh stability is demonstrated to be achievable through the utilization of a systematic multifactorial approach in this study. EG‐OFETs with operational stability and lifetime several orders of magnitude higher than the state of the art have been fabricated by carefully controlling a set of intricate stability‐limiting factors, including contamination and corrosion. The indacenodithiophene‐co‐benzothiadiazole (IDTBT) EG‐OFETs exhibit operational stability that exceeds 900 min in a variety of widely used electrolytes, with an overall lifetime exceeding 2 months in ultrapure water and 1 month in various electrolytes. The devices were not affected by electrical stress‐induced trap states and can remain stable even in voltage ranges where electrochemical doping occurs. To validate the applicability of our stabilized device for biosensing applications, the reliable detection of the protein lysozyme in ultrapure water and in a physiological sodium phosphate buffer solution for 1500 min was demonstrated. The results show that polymer‐based EG‐OFETs are a viable architecture not only for short‐term but also for long‐term biosensing applications.

Encapsulation of ruthenium oxide nanoparticles in nitrogen-doped porous carbon polyhedral for pH-universal hydrogen evolution electrocatalysis

The development of pH-universal HER electrocatalyst with Pt-like activity remains challenged yet critical for hydrogen energy systems. Herein, we have successfully immobilized RuOx nanoparticles on the surface of C–N derived from zeolitic imidazolate frameworks (RuOx@C–N). The obtained RuOx@C–N exhibits Pt-like HER performance with overpotential of as low as 14 and 93 mV to drive the current density of −10 and −100 mA cm−2 in 1.0 M KOH, respectively. Furthermore, RuOx@C–N exhibits an unexpected mass activity of 0.81 A cm−2 mgRuOx−1, which is even superior to benchmark Pt/C. Such an improvement is attributed to RuOx@C–N heterostructure, which will facilitate the electron transfer due to the Mott-Schottky effect. Additionally, the nitrogen-doped carbon framework will efficiently adjust the electronic structure of metallic catalytic sites and optimize the kinetics of catalytic reaction. Benefiting from the Mott-Schottky effect, the RuOx@C–N electrocatalysts exhibit pH-universal catalytic performance toward hydrogen evolution in various electrolytes, corroborating its university and facility in industrial hydrogen production. This approach offers a facile and versatile strategy for the development of Ru-based electrocatalysts with high performance and robust stability.

Highly efficient electrocatalytic degradation of methylparaben using BiOx-doped Ti/β-PbO2 anode: Comprehensive electrochemical study and degradation mechanism

Electrochemical degradation of methylparaben (MPB) was successfully performed using Ti/β-PbO2-BiOx anode. The structure of the fabricated electrode was characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), and mapping techniques. The results confirmed the successful preparation of the electrode with favorable morphological and structural properties. This research includes optimization of operating parameters such as solution pH, applied current density, initial MPB concentration and electrolysis time. The results indicate that the prepared electrode has high electrochemical performance and thermal stability. Under optimal conditions, current density of 4.8 mA/cm2, pH = 5 and initial concentration of 0.5 mM, the maximum degradation efficiency of 98.9 % was obtained. In this work, also, based on the data obtained from LC-MS analysis, a detailed mechanism for the degradation of MPB was proposed. In another section of this research, the electrochemical behavior of MPB on glassy carbon electrode was comprehensively studied using cyclic voltammetry at different pH values. The data obtained from this study provide significant insight into the electrochemical behavior of MPB, its pH-dependent properties and adsorption activities. The results of this section can also be used to better optimize the conditions of MPB degradation.