Three-dimensional Honeycomb Research Articles

Nitrogen-Rich Barium-Organic Framework for Capture and Cocatalysts Free Chemical Fixation of CO2 via Cyclic Carbonates and Oxazolidinones.

The carbon dioxide (CO2) capture and utilization strategy has emerged as an innovative and multifaceted approach to counteract carbon emissions. In this study, a highly porous muffin polyhedral barium (Ba) ̵ organic framework (BaTATB; H3TATB = 4,4',4″-s-triazine-2,4,6-triyl-tribenzoic acid) was synthesized solvothermally. The three-dimensional honeycomb pore architectures were densely populated with Lewis acidic Ba(II) metal sites and basic nitrogen-rich triazines. BaTATB demonstrated selective CO2 adsorption with a high heat of adsorption. Its abundance of Lewis acidic (Ba clusters) and basic (triazine) sites makes BaTATB an ideal catalyst for the cycloaddition of CO2 to epoxides in two- and three-component reactions. Furthermore, BaTATB is an exceptional recyclable catalyst for CO2 cycloaddition to epoxides and aromatic amines, enabling the high-yield synthesis of cyclic carbonates and oxazolidinone at 1 bar of CO2 under moderate, solvent-free, and cocatalyst-free conditions. Additionally, BaTATB was recycled for nine and seven consecutive cycles of cyclic carbonate and oxazolidinone synthesis with no substantial decrease in catalytic activity. Using density functional theory, we demonstrated the rational design of polyhedral metal-organic frameworks with Lewis acidic and basic sites that exhibit excellent cocatalyst-free CO2 conversion.

Ultralight and robust polyimide aerogels with tunable porous structures based on cation-π interactions for superior thermal insulation

Polyimide (PI) aerogels, renowned for their ultra-low density and exceptional porosity, exhibit substantial potential for thermal insulation applications. However, conventional freeze-drying method often produces irregular and large pore structures, which compromise the mechanical properties of PI aerogels and limit their practical applications. In this work, the enhanced PI-Cu aerogels by cation-π interactions are fabricated through the introduction of Cu ions and benzimidazole. The findings reveal that cation-π interactions facilitate the transformation of PI aerogels from two-dimensional layered structure to three-dimensional honeycomb structure characterized by smaller and more uniform pores, significantly reducing shrinkage and leading to ultra-light properties. Remarkably, a significant improvement of mechanical performance is also achieved after introducing cation-π interactions, even at a decreased density (0.046 g/cm3). Specifically, for samples with 3.5 wt% solid content, the yield strength and modulus of PI-Cu aerogels increase to 0.71 MPa and 13.58 MPa, respectively, representing improvements of 344 % and 520 % over pristine PI aerogels, which are superior to those of many other previously reported PI aerogels/foams with similar or even higher densities. Additionally, the toughness is significantly elevated from 13.5 MPa to 48.8 MPa. More importantly, after introducing cation-π interactions, the thermal insulation of PI-Cu aerogels are also improved with thermal conductivity decreasing from 0.04214 to 0.03997 W/m·K in axial direction and from 0.0399 to 0.03688 W/m·K in radial direction at 25°C. Interestingly, the thermal conductivity show only a slight increase under 180°C less than 0.05741 W/m·K in axial direction and 0.04923 W/m·K in radial direction owning to their exceptional thermal stability (Tg = 404 °C, T5%=524 °C). These exceptional properties position PI-Cu aerogels as promising candidates for diverse functional applications in the field of energy conservation.

Influence of Internal Architecture and Ink Formulation on the Thermal Behavior of 3D-Printed Cementitious Materials.

Cement-based 3D printing provides an opportunity to create cement-based elements with a hierarchy of structures and patterns that are not easily achievable using traditional casting techniques, thereby providing new possibilities for improving thermal control and energy storage in cement-based materials. In this study, the influence of internal architecture and ink formulation on the thermal behavior of 3D-printed cement composite beams was investigated using infrared thermal imaging and a conceptual one-dimensional heat transfer model based on cooling fins in convective media. Three-dimensional printed beams with rectilinear, three-dimensional honeycomb, and Archimedean chord infill patterns and cement ink formulations with and without 5% halloysite nanoclay were exposed to a heating source at one end. The thermal behavior of the beams was found to be predominantly influenced by their internal architecture rather than the cement ink formulation, with differences in void structures and heat transfer pathways among the different architectures resulting in a hierarchy of apparent thermal conductivity. The internal architecture resulted in a reduction in apparent thermal conductivity by up to 75%, while the incorporation of halloysite nanoclay in the cement ink led to a reduction of up to 14%. Among the tested internal architecture, the rectilinear architecture showed a 10-15% higher apparent thermal conductivity compared to the three-dimensional honeycomb architecture and a 35-40% higher apparent thermal conductivity than the Archimedean architecture. The research demonstrates a promising strategy for fabricating and evaluating cement-based materials with thermal management capabilities using 3D printing methods.

Effect of Three-Dimensional auxetic honeycomb core on behavior of sound transmission loss in shallow sandwich cylindrical shell

The primary objective of this research is to examine the sound transmission loss (STL) in a shallow sandwich cylindrical shell featuring a 3D auxetic honeycomb core. Initially, the 3D elasticity theory was employed by applying the state vector method and extracting both local and global transfer matrices to calculate STL relations for the cylindrical shell, including the auxetic honeycomb core. Subsequently, boundary conditions were applied to calculate the unknowns, eventually leading to a relationship for calculating STL within the structure. The derived equations were numerically solved using MATLAB software. The validity of the results obtained using this method was examined by comparing them with the findings of other researchers. Moreover, a comparison was conducted involving a large ratio of the curvature radius to thickness, considering both the auxetic honeycomb core and aluminum with equal mass. The results demonstrate a significant increase in STL when utilizing this auxetic honeycomb core compared to a material with the same mass. Specifically, at a frequency of 2 Hz, a significant enhancement of about 29.44 % in STL is observed when increasing the core thickness from 10.39 mm to 20.39 mm. Furthermore, STL results have been obtained for various thicknesses, radius of curvature, and incident angles.

Highly Efficient and Selective Hydrodeoxygenation of Guaiacol Using Ni-Supported Honeycomb-Structured Biochar and Phosphomolybdic Acid.

The sustainable development of energy has always been a concern. Upgrading biomass catalysis into hydrocarbon liquid fuels is one of the effective methods. In order to upgrade biomass derivative guaiacol by Hydrodeoxygenation (HDO) catalysis, this article report a three-dimensional honeycomb structure biochar loaded with Ni nanoparticles and phosphomolybdic acid demonstrating excellent catalytic performance in a short period of time. This is due to the porous structure of biochar, which allows Ni metal nanoparticles to be highly uniformly dispersed on the support, which enhances the catalytic hydrogenation of guaiacol in terms of both rate and efficiency. Furthermore, it was observed that the added phosphomolybdic acid dissolved within the temperature range of 78-90 °C, functioning as a homogeneous catalyst in the process. This proves advantageous, as the phosphomolybdic acid becomes accessible at any location within the porous Ni/C catalyst. The detailed characterization data revealed that the carbon support prepared in this study has a high specific surface area of up to 1375.61 m2/g. Additionally, the phosphomolybdic acid exhibited rich acidity, with Brønsted and Lewis acid contents of 2.55 μmol/g and 21.45 μmol/g, respectively. Reaction data demonstrated that at 240 °C for 180 min, 100 % conversion and 97.9 % cyclohexane selectivity were achieved. This study introduces a bifunctional catalyst with an unique catalyst's structure, facilitating a heterogeneous-homogeneous catalytic reaction and delivering an efficient catalytic effect.

Effects of phosphorylation-modified long-chain inulin on wheat starch: Physicochemical properties and retrogradation behaviors

In this research, modification of long-chain inulin (FXL) through phosphorylation (PFXL) to enhance its application in wheat starch (WS) and starch-based products. The impacts of PFXL on the pasting, rheology, microstructure, and retrogradation characteristics of WS were researched. The findings revealed that PFXL significantly reduced both the breakdown and setback values of WS. Additionally, the incorporation of PFXL reduced the viscoelasticity of WS paste and improved its fluidity. Scanning electron microscopy indicated that higher PFXL levels (>5 %) produced small fragments that partially covered the three-dimensional honeycomb structure of WS paste, thereby reducing water loss during short-term storage. PFXL also altered water distribution in WS gels, depending on concentration and storage duration. X-ray diffraction and Fourier-transform infrared spectroscopy suggested that PFXL effectively inhibited amylopectin recrystallization. Compared to FXL, PFXL exhibited a more pronounced ability to inhibit the aging of WS in short- and long-term storage.

Genetic-algorithm-assisted design of chiral honeycomb membrane acoustic metamaterials for broadband noise suppression

Low-frequency sound wave reduction is hardly feasible for traditional sound absorbers such as porous media. In contrast, locally resonant acoustic metamaterials act as spatial frequency filters, effectively reducing low-frequency noise. However, these materials can have narrow bandgaps, add extra mass to the main system, and function only within a specifically adjusted frequency range. Therefore, this paper proposes a methodology for designing three-dimensional (3D) chiral honeycomb membrane-type acoustic metamaterials (MAM) based on acoustic circular dichroism (ACD), negative effective mass, and local resonance mechanisms (LRM). The paper also uses the genetic algorithm (GA) to maximize sound transmission attenuation and widen bandgaps. The accuracy of the simulations is validated with available experimental data. The key idea of the present study is to automatically design a MAM structure using modern optimization tools. A developed GA aims to maximize the average sound transmission loss (STL) across the desired low-frequency range of 0–850 Hz by optimizing the value of structural parameters associated with the configurations of masses, including rotation and linear offset, as well as their geometrical dimensions, including length and width. COMSOL Livelink with MATLAB is employed as a practical co-simulation tool to find an optimum value for structural parameters. Results indicate a 35% improvement in average STL along with an ultra-wide bandgap with a 507% bandgap coverage factor (BGCF) in the frequency range of interest, verifying the reliability of the developed algorithm. In addition, sound mitigation incidence is justified by exploring the negative effective parameters of the unit cell and displacement vector fields. The proposed designs demonstrate superior performance as both initial and optimized models broke the mass law within the investigated frequency range. Finally, the effect of the selected geometrical parameters on the objective function is observed through sensitivity analysis. This study presents the practical use of optimization algorithms to develop MAMs.

Design-manufacturing-performance of electromagnetic absorbing/load bearing three-dimensional honeycomb woven composites

Structural electromagnetic wave (EMW) absorbing composites play a critical role in both civilian and military applications. However, traditional sandwich honeycomb EMW absorbing composites have poor out-of-plane mechanical properties and load-bearing performance.This study introduces the development of a three-dimensional honeycomb woven composite (3DHWC) that integrates EMW absorption and load-bearing capabilities. A weaving loom was used to fabricate a three-dimensional honeycomb woven structure fabric (3DHSWF) with varying structural parameters. Subsequently, the composites were formed using carbon black (CB), multi-walled carbon nanotubes (MWCNTs), and carbonyl iron powder (CIP) as hybrid absorbers, epoxy resin as the matrix, combined with the vacuum-assisted resin transfer molding (VARTM) process. Testing confirmed the material’s excellent EMW absorption and mechanical properties, achieving a maximum reflection loss (RL) of −30.9 dB and an adequate EMW absorption bandwidth (EAB) of 14.58 GHz. The maximum bending load reached 5799.1 N, with no delamination observed in the samples. This material demonstrates outstanding EMW absorption performance and exhibits superior load-bearing capacity while maintaining structural integrity. Our research provides valuable insights into the design of honeycomb EMW absorbing composites, offering significant advancements in EMW absorption efficiency and bending mechanical properties.

Comprehensive analysis of charge carriers dynamics through the honeycomb structure of graphite thin films and polymer graphite with applications in cold field emission and scanning tunneling microscopy

Polymer graphite electron sources have performed satisfactorily as field emission emitters and scanning tunneling microscopy probes in the past few years. However, the emission process was characterized by limited total emission currents. This paper introduces the elemental, vibrational, electronic structure, and optical analysis of polymer graphite and glass-graphite composite field emission cathodes to study these limitations. Moreover, the field emission characteristics are studied including the changes in the potential energy barrier of the used materials and structures. Among the studied structures, the cathodes prepared from graphite thin films deposited on a micropointed glass substrate (film-GMF) showed superior performance as random field emission arrays. This includes obtaining much higher emission current values ≈ 20 times) and lower threshold voltages ≈ 1/2) compared to the results obtained from polymer graphite samples. The enhancement factor in such emitters is believed to be the three-dimensional honeycomb structure of graphite. Moreover, the study includes applying graphite coatings to tungsten nano-field emission cathodes and scanning tunneling microscopy probes, which improves the performance of such cathodes/probes in both microscopic techniques.

Breaking new ground in metal-ion battery anodes: First principles design of Dirac nodal line semimetallic carbon materials

With the rapid development of electronic devices, the demand for batteries has gradually increased, and existing batteries can no longer satisfy it. In this paper, a three-dimensional honeycomb carbon material is designed and termed pmma-C32. The mechanical stability, dynamic stability, thermal stability, and mechanical stability were investigated through first-principles molecular dynamics, phonon spectrum, and the Born-Huangkun criterion. The calculation results show that pmma-C32 not only has good thermodynamic stability, but also has static stability. Similar to graphene, pmma-C32 exhibits semi-metallic characteristics, featuring two Dirac node lines with high Fermi velocity, indicating a high capacity for electron transport. As a metal-ion battery material, pmma-C32 exhibits higher theoretical capacity(836.8, 732.2, and 418.4 mA h/g for Li, Na, and K), lower diffusion barrier (0.06–0.12 eV for Li, 0.10–0.11 eV for Na, and 0.05–0.06 eV for K), and lower open circuit voltage (0.34 V for Li, 0.37 V for Na, and 0.74 V for K). These remarkable properties endow semimetallic pmma-C32 as a promising anode material for metal-ion batteries, providing fast charge and discharge rates. This research not only broadens the family of three-dimensional carbon materials, but also greatly improves the performance for universal metal-ion battery anode materials through material structure design.

Three-dimensional honeycomb structured BaTiO3-based piezoelectric ceramics via texturing and vat photopolymerization

Textured piezoelectric ceramics have attracted significant attention due to their ability to achieve ultra-high piezoelectric properties comparable to single crystals at a lower cost. Traditional processing techniques, such as tape casting, can efficiently produce textured piezoelectric ceramics with simple structures but are inadequate for fabricating three-dimensional structures with high complexity, thereby limiting their applications in specific fields. Vat photopolymerization (VPP), an advanced additive manufacturing technology, can rapidly and accurately create intricate three-dimensional structures. Crucially, VPP can provide the necessary shear force to align the templates, resulting in the highly-textured piezoelectric ceramics. In this study, BaTiO3-based piezoelectric ceramics with a high degree of texture (97.2 %) were produced using VPP technology. These ceramics exhibited a large piezoelectric coefficient (d33 = 511 pC/N), which was 66 % higher than that of non-textured ceramics. Furthermore, textured ceramics with a honeycomb structure were fabricated, demonstrating their potential in sensing applications. This work confirms the feasibility of using VPP technology to prepare high-performance, complex-structured textured ceramics, thereby promoting the development and application of textured piezoelectric ceramics.

Experimental study on selected properties and microstructure of pine-based wood ceramics

Abstract Wood ceramics using biomass materials as templates possess the benefits of facile fabrication and versatile applicability. To investigate the physical properties, chemical properties and microstructure of wood ceramics prepared from biomass materials, the basic properties and potential applications of wood ceramics were expounded. In this paper, wood powder wood ceramics (WPWC) and wood fiber wood ceramics (WFWC) were prepared through the vacuum carbonization method, utilizing pine powder and pine fiber as raw materials. The impact of phenolic resin concentration and mixture filling mass on various properties of wood ceramics, including mass loss rate (MLR), volume shrinkage rate (VSR), apparent porosity (AP), and bending strength (BS) were investigated on this basis. The microtopography and pore structure of wood ceramics were also analyzed. The test results show that an increase in the concentration of phenolic resin led to a decrease in the MLR, VSR, and AP of WPWC and WFWC, while their BS exhibited an increase. When the concentration of phenolic resin was 60 %, the phenolic resin yielded a BS of 8.70 MPa and 9.20 MPa for WPWC and WFWC, respectively. Furthermore, the microstructures of both WPFC and WFWC reveal hierarchical porous structures. The difference is that WPFC has a dispersed three-dimensional network topology in its overall morphology, which is mainly formed by filamentous or long linear glass carbon in wood ceramics dominated by carbon. The natural and consistent pore structure of WFWC is comparable to a three-dimensional honeycomb structure, the primary mesoporous size was around 40.28 nm and the main macropore size was more than 10,000 nm. It elucidates the pore structure of WPWC and WFWC, characterized by “hierarchical porosity”, the differences and relationships between porous wood ceramics derived from powdery and fibrous biomass as raw materials were analyzed, which contributes to the advancement of the fundamental principles of wood ceramics and establishes a theoretical basis for the practical exploration and development of biomass materials.

A novel coupling-induced strength-improved three-dimensional honeycomb with positive-negative dual Poisson's ratios

By combining the Re-entrant (RE) cell with the hexagonal (HE) cell, this study proposes a novel three-dimensional honeycomb called Re-entrant-hexagonal-coupling (RHC) honeycomb to improve the strength of a single structure. The deformation modes and the strength of the honeycomb are comprehensively investigated through experimental and numerical methods. Results indicate that the deformation of the RHC honeycomb exhibits a clear coupling effect due to the opposite deformation of the RE and HE honeycombs, resulting in a quasi-zero Poisson's ratio mode and a significant strength enhancement. The coupling-induced enhancement (CIE) of the RHC honeycomb remains consistently higher than 0.585, demonstrating clear superiority over the other two comparative honeycombs. Besides, adjusting the thickness ratio can effectively balance the coupling effect and auxetic effect, thereby enhancing the specific energy absorption at a given relative density. This study offers valuable guidance for the design and research of such coupling auxetic honeycomb structures, warranting further attention.

Design and testing of novel three-dimensional modular negative stiffness honeycomb structures as reusable crash absorbers

Conventional crash absorbers dissipate kinetic energy of impacts into plastic irreversible deformation, needing an immediate replacement to restore safety of the structure, highly increasing cost and inconvenience of the system. Aim of the present work was to develop innovative prototypes of reusable crash absorbers, able to withstand multiple collisions . A novel design was proposed, based on a modified Negative Stiffness Honeycomb (NSH) approach, using a three-dimensional modular layout with the objective of improving performance, reliability, and functionality of the device in repeated impacts. Two prototypes were manufactured to prove the concept. The first was produced in Nylon PA 6/66 by fused deposition modelling, while the second was obtained from laser-cut plates of stainless steel AISI 304. The nylon prototype was evaluated in cyclic static compression and dynamic impact tests, while the performance of the steel prototype was assessed only in impact tests. Results show improved values of energy absorption with respect to previous studies using bidimensional NSH energy absorbers and a highly reliable behaviour in multiple dynamic compression tests. Moreover, the nylon prototype featured a novel behaviour during impact tests, with autonomous delayed recovery of deformation after the collision. Our data show that three-dimensional modular NSH approach is effective in obtaining a reusable crash absorber, with improved performance and functionality compared to previously proposed design. This work can be considered a step forward in the search for alternative crash absorbers able to sustain multiple impactsbefore substitution, with potential advantages when their replacement is either impossible or too expensive.

Nano-silicon embedded in 3D honeycomb carbon frameworks as a high-performance lithium-ion-battery anode

The fabrication of three-dimensional (3D) honeycomb carbon frameworks, incorporating embedded silicon (Si) nanoparticles (NPs), is successfully achieved through a facile method involving mixing, carbonization, and acid pickling. The as-prepared Si@PVPC composites exhibit excellent electrochemical performances due to reasons as follows. (1) Honeycomb channels supply enough space to accommodate the expansion of Si NPs and so structural integrity of 3D honeycomb carbon frameworks are maintained during lithiation/delithiation processes. (2) Honeycomb channels offers fast transfer paths for Li-ion diffusion. (3) 3D carbon frameworks afford reliable and stable electric contact points. As a result, Si@PVPC electrodes show a capacity of 1294.3 mAh g−1 at 2 A g−1 after 1400 cycles with a capacity retention of 85.5 %. Even at an ultrahigh current of 16 A g−1, Si@PVPC electrodes still show a capacity of 619.6 mAh g−1.

Investigation of bending behavior of two and three-dimensional honeycomb and auxetic sandwich beams

The bending behavior of two (2D) and three-dimensional (3D) sandwich beams that have a negative Poisson’s ratio (auxetic) and conventional honeycomb was investigated for different geometries, sheet thicknesses, and cell thicknesses. The re-entrant and solid specimens were produced with a stereolithographic (SLA) 3D printer and subjected to a three-point bending test under the conditions specified in the ASTM C393 standard. The data obtained from the tests were used to verify finite element analysis (FEA) results. The radius of curvatures was calculated for each specimen depending on the load step. In addition, Poisson’s ratio was calculated for each auxetic sample. As a result, the 3D arrowhead beam, with a cell thickness of 1 mm and a sheet thickness of 2 mm, exhibits peak force values that are 497.340% and 461.500% higher than re-entrant and missing rib beams, respectively. Besides, the maximum strain energy values of same 3D arrowhead specimens (596.120 mJ) are higher than re-entrant (101.032 mJ) and missing rib (108.201 mJ) specimens. It was determined that the arrowhead is the most durable structure compared to other auxetic structure geometries. Therefore, when arrowhead and honeycomb 3D beams are compared, it was observed that the maximum strain energy of arrowhead specimens was higher in both horizontal (84.310%) and perpendicular (131.910%) positioned specimens. Comparing the arrowhead and honeycomb 2D beams with the highest maximum strain energy, it can be concluded that the arrowhead beam absorbs 20.000% more energy.

Two-dimensional Ti3C2Tx anchored on three-dimensional SiC honeycomb framework for efficient and cyclic photocatalytic degradation of organic pollutants

The excellent recyclability of SiC foam renders it an ideal catalyst in the field of photocatalytic degradation, however to further improve its photocatalytic efficiency remains a major challenge in current research. In this regard, a honeycomb-like porous SiC foam was successfully constructed through freeze-drying and polymer-to-ceramic derivation method, with two-dimensional Ti3C2Tx nanosheets anchored on its three-dimensional framework. Their photocatalytic performances were evaluated by the degradation of methylene blue (MB) under visible-light irradiation. All Ti3C2Tx/SiC hybrid foams show superior photocatalytic degradation capability compared with SiC foam, with a highest removal rate (adsorption and degradation) reaching 94.4% for TSF-4, denoting an increasement of 50.4%. Even after five cycles, the removal rate remained at 91.4% with only a slightly loss of 3%, suggesting its excellent recycling performance. These desirable results stem from the unique structural design, in which the porous structure facilitates the contact between catalyst and pollutant, while the Ti3C2Tx/SiC heterojunction promotes effective separation of photogenerated carriers. This work paves the way for the development of lightweight, efficient and easily recyclable photocatalyst for wastewater purification.

Exploring the effect of different precursor materials on Fe-loaded biochar catalysts for toluene removal

Rice husks, camphor tree leaves, and corn stalks were selected as raw materials from shell, leaf, and stem biomass, respectively, to prepare Fe-loaded biochar catalysts, and the removal efficiency of toluene by the three catalysts was determined. The removal efficiencies of shell catalyst (ARHB-Fe) and stem catalyst (ACSB-Fe) were 89.68% and 90.97%, respectively, both lower than that of leaf catalyst (ACLB-Fe), which was 92.01%. ARHB-Fe and ACSB-Fe exhibited a fibrous structure, while ACLB-Fe exhibited a three-dimensional honeycomb structure. ARHB-Fe had the largest specific surface area at 284.65 m²/g, exhibiting excellent physical adsorption performance for toluene. A cross-comparison of the existing forms of Fe in the three catalysts was conducted. The highest Fe2+ content in ARHB-Fe was 45.64%. The highest Fe3+ content in ACLB-Fe was 46.76%. Fe3+ underwent electrostatic reactions with the benzene ring, enhancing the adsorption of toluene. The highest Fe3C content in ACSB-Fe was 18.20%. At high temperatures, Fe3C decomposed to produce Fe0, possessing strong reducing ability and high reactivity, which effectively promoted the catalytic cracking of toluene. ARHB-Fe and ACSB-Fe were mainly influenced by n–π interactions (C–O functional groups). ACLB-Fe exhibited the combined effects of hydrogen bonding interactions (–OH functional groups), n–π interactions, and π–π interactions (CC functional groups). Furthermore, ACLB-Fe possessed the most abundant acidic sites and the highest acidity.

Three-dimensional honeycomb composites consist of metal carbides and layered double hydroxides for high-performance supercapacitor electrode materials

To achieve excellent electrochemical performance and stability, a composite material based on metal carbides (MXene) and CoNiZn layered double hydroxides (LDHs) has been synthesized, which synergistically combines the high electrical conductivity of MXene with the high theoretical specific capacity of LDHs. The as-prepared three-dimensional honeycomb-structural MXene/CoNiZn LDH composites have excellent cycle stability with a capacitance retention rate of 87.8% after 100,000 cycles and outstanding electrochemical activity with a specific capacitance of 2044.9 F g−1 at a scan rate of 5 mV s−1. Furthermore, electrochemical impedance spectroscopy also shows a reduced internal resistance indicating that the honeycomb-porous structure facilitates electron transfer and ion diffusion. This study provides a feasible route to develop high-performance supercapacitor electrode materials.

A novel three-dimensional orthogonal star honeycomb structure with negative Poisson’s ratio

A novel three-dimensional(3D) orthogonal star honeycomb structure with increased strength and negative Poisson’s ratio(NPR) performance that is not subject to angle constraints was proposed, and the calculation model of Young’s modulus and Poisson’s ratio of the cell structure under axial load was derived in this study. Through the investigation of the deformation mode and the finite element (FE) research results of the structure, it is found that the longitudinal length parameter l2 and angle parameter θ2 are important concave axes that affect the mechanical properties of materials. The quasi-static compression experimental results shows that the constraints of adjacent elements can enhance the strength of the structure to a certain extent, and the theoretical analysis results and the FE simulation results were in good agreement with the experimental results. In addition, the results are also concluded that the prediction of Young’s modulus and Poisson’s ratio and the designability of mechanical properties of 3D orthogonal star honeycomb structures could be achieved by the theoretical calculation formula derived in this study.