Preferential Growth Research Articles

Unique flake-shaped sulfur morphology favored by the binder-free electrophoretically deposited TiO2 layer as a promising cathode structure for Li-S batteries

Metal oxides have been extensively studied as catalyst additives in Li-S batteries due to their high affinity for soluble lithium polysulfides (LiPSs). The present study developed a novel carbon nanomaterials- and binder-free 3D sulfur host by electrophoretic deposition (EPD) of TiO2 nanoparticles on carbon fiber paper (CFP). Benefiting from the unique well-connected TiO2 porous layer formed by EPD, the initial discharge capacity of Li-S battery was increased from 1160 mAh g−1 in conventional cast TiO2/binder/S cathode (Cast:CFP/PVDF/TiO2/S) to 1310 mAh g−1 in the EPD:CFP/TiO2/S cathode, along with an overpotential drop of 16 %. Electron microscopic studies at 100% state-of-charge (SoC) revealed that while notorious sulfur particulates were formed on Cast:CFP/PVDF/TiO2/S, the surface of EPD:CFP/TiO2/S was covered with flake-shaped sulfur precipitates. The formation of sulfur flakes effectively suppressed pulverization in EPD:CFP/TiO2/S, leading to superior electrochemical performance and cycle life. Microstructural studies and real-time EIS investigations revealed that sulfur flakes nucleated across the Li2S matrix at the initial stages of charge and grew vertically from the sulfur/TiO2 interface. The preferential growth mechanism of sulfur flakes was attributed to the superior surface conductance of the EPD-TiO2 film enabled by the ordered clusters formed during EPD, enhancing the kinetics of electrocatalytic reactions of polysulfides at the TiO2/sulfur interface. Our results show that developing novel methods to modify the morphology of secondary sulfur upon cycling is critical for enhancing charge-discharge performance in Li-S batteries.

Mesoporous structured MoS2 as an electron transport layer for efficient and stable perovskite solar cells.

Mesoporous structured electron transport layers (ETLs) in perovskite solar cells (PSCs) have an increased surface contact with the perovskite layer, enabling effective charge separation and extraction, and high-efficiency devices. However, the most widely used ETL material in PSCs, TiO2, requires a sintering temperature of more than 500 °C and undergoes photocatalytic reaction under incident illumination that limits operational stability. Recent efforts have focused on finding alternative ETL materials, such as SnO2. Here we propose mesoporous MoS2 as an efficient and stable ETL material. The MoS2 interlayer increases the surface contact area with the adjacent perovskite layer, improving charge transfer dynamics between the two layers. In addition, the matching between the MoS2 and the perovskite lattices facilitates preferential growth of perovskite crystals with low residual strain, compared with TiO2. Using mesoporous structured MoS2 as ETL, we obtain PSCs with 25.7% (0.08 cm2, certified 25.4%) and 22.4% (1.00 cm2) efficiencies. Under continuous illumination, our cell remains stable for more than 2,000 h, demonstrating improved photostability with respect to TiO2.

Enhancing magnetostriction in FeAl alloys via crystal growth orientation tuning by a trace amount of Pt doping

Iron-based cubic alloy systems opened the door to the development of magnetostrictive materials with moderate magnetostriction, low cost, and good mechanical properties. At the as-cast state, the grain growth orientation of these alloy systems is close to random, which deteriorates magnetostriction. Doping with certain elements can tune the growth orientation to enhance magnetostriction. However, the driving force for the crystal growth along preferential orientation is still not clear. Here in this work, revealed by density functional theory (DFT) calculation, Pt doping can tune the crystal growth direction of FeAl along <100> crystal direction (same as easy magnetization direction), which can be utilized to realize 90° domain-switching and thus magnetostriction is enhanced greatly. These are confirmed by experimental results. The magnetostriction increases from 29 ppm to 80 ppm, representing a 176% enhancement through doping with 0.4 at.% Pt. The maze magnetic domain structures, observed by magnetic force microscope, are also preferentially <100> oriented and feature stripes. In consideration of the similarity between this study and our previous study on FeGa alloy (C. Zhou et al., 2020), it can be expected that our methods can be extended to other magnetostrictive materials and help develop polycrystals with desired orientations.

Customizing H2O‐Poor Electric Double Layer and Boosting Texture Exposure of Zn (101) Plane towards Super‐High Areal Capacity Zinc Metal Batteries

The catastrophic dendrite hyperplasia and parasitic reactions severely impede the future deployment of aqueous Zn‐ion batteries. Controlling zinc orientation growth is considered to be an effective method to overcome the aforementioned concerns, especially for regulating the (002) plane of deposited Zn. Unfortunately, Zn (002) texture is difficult to obtain stable cycling under high deposition capacity resulting from its large lattice distortion and nonuniform distribution in electric field. Herein, different from traditional cognition, a crystallization orientation regulation tactic is proposed to boost Zn (101) texture exposure and inhibit zinc dendrite proliferation during plating/stripping. Experimental results and theoretical calculations demonstrate the malate molecules preferentially adsorb on the Zn (002) facet, leading to the texture exposure of distinctive Zn (101) plane. Meanwhile, the –COOH and –OH groups of malate molecules exhibit strong adsorption on the Zn anode surface and chelate with Zn2+, achieving H2O‐poor electrical double layer. Very impressively, the multifunctional malate additive enlists zinc anode to survive for 600 h under a harsh condition of 15 mAh cm−2/15 mAh cm−2. Moreover, the symmetric cell harvests highly‐reversible cycling life of 6600 h at 5 mA cm−2/1.25 mAh cm−2, remarkably outperforming the ZnSO4 electrolyte. The assembled Zn//MnO2 full cells also demonstrate prominent electrochemical reversibility.

Customizing H2O-Poor Electric Double Layer and Boosting Texture Exposure of Zn (101) Plane towards Super-High Areal Capacity Zinc Metal Batteries.

The catastrophic dendrite hyperplasia and parasitic reactions severely impede the future deployment of aqueous Zn-ion batteries. Controlling zinc orientation growth is considered to be an effective method to overcome the aforementioned concerns, especially for regulating the (002) plane of deposited Zn. Unfortunately, Zn (002) texture is difficult to obtain stable cycling under high deposition capacity resulting from its large lattice distortion and nonuniform distribution in electric field. Herein, different from traditional cognition, a crystallization orientation regulation tactic is proposed to boost Zn (101) texture exposure and inhibit zinc dendrite proliferation during plating/stripping. Experimental results and theoretical calculations demonstrate the malate molecules preferentially adsorb on the Zn (002) facet, leading to the texture exposure of distinctive Zn (101) plane. Meanwhile, the -COOH and -OH groups of malate molecules exhibit strong adsorption on the Zn anode surface and chelate with Zn2+, achievingH2O-poorelectrical double layer. Very impressively, the multifunctional malate additive enlists zinc anode to survive for 600 h under a harsh condition of 15 mAh cm-2/15 mAh cm-2. Moreover, the symmetric cell harvests highly-reversible cycling life of 6600 h at 5 mA cm-2/1.25 mAh cm-2, remarkably outperforming the ZnSO4 electrolyte. The assembled Zn//MnO2 full cells also demonstrate prominent electrochemical reversibility.

In situ construction of one-dimensional structures induced by Ba doping in Al2O3-TiO2 ceramics derived from quenched powders

In this work, we propose a strategy for in situ construction of rod-like grains in Al2O3-TiO2 ceramics through Ba doping. Ba-doped Al2O3-13 wt% TiO2 composite powder was initially synthesized using combustion synthesis-air atomization, where feedstocks were melted by the Al-O2 combustion reaction and subsequently atomized and rapidly cooled in air, producing quenched powders rich in metastable phases. Upon heat treatment at 1100℃, the metastable phases transformed into stable forms, accompanied by phase separation and solid solution precipitation. Notably, Ba doping induced the formation of rod-like hollandite grains with preferential growth along the [001] direction. Bulk ceramics were prepared through pressureless sintering, and the sample sintered at 1350℃ exhibited a hardness of 14.14±0.61GPa and a fracture toughness of 5.17±0.49MPa∙m1/2. The toughening behavior of rod-like grains, including crack deflection and pull-out/bridging effects, was observed. This study provides insights into the evolution of quenched oxides and the design of ceramic microstructures.

Formation of seaweed morphology and enhancing mechanical properties of an A356 alloy by directional solidification

In the present work, regular dendrite and seaweed pattern are produced by controlling the crystal orientation during directional solidification of an A356 aluminium alloy. These morphologies and growth orientation were investigated by electron backscatter diffraction (EBSD), and the results showed that the seaweed pattern mainly prevailed under the (100)[011] orientation. At the same time, the effects of seaweed pattern in the properties of A356 alloy were analysed by room temperature tensile test. It was found that the elongation and toughness of the samples reached 20% and 36J/m3, respectively, for the seaweed; 13% and 24J/m3, respectively, for the regular dendrites; and 8% and 14J/m3, respectively, for the cast ingot. Compared with the regular dendrite samples, the seaweed pattern obtained relatively excellent elongation and toughness. By using scanning electron microscopy (SEM), it is found that the distribution of eutectic silicon particles in seaweed morphology sample is more refined and uniform, which is the main reason for these enhancements.

Effect of Tween 80 on the Electrocatalytic Performance of a Ti/PbO2‐MWCNTs Electrode

AbstractIn this work, Ti/PbO2‐MWCNTs anodes modified with different amount with different amount of Tween 80 (0.0–2.0 g/L) were prepared by the direct current electrodeposition method used as anode materials for Zinc electrowinning. The MWCNTs were dispersed in a lead nitrate solution with Tween 80, and the effects of the amount of added Tween 80 on the morphology, phase composition and electrocatalytical performance of lead dioxide coating were investigated. Physical characterizations show that with the increase of the amount of Tween 80, both grain size of PbO2 and carbon content in PbO2 layer firstly increased and then decreased, the preferential orientation and crystallinity of the PbO2 grain growth in the deposition process changed. Electrochemical tests demonstrate that the optimal modified electrode achieved the minimum Eo value and maximum j0 of 2.038 V and 3.781×10−4 A, respectively, an increase of capacitance to 368.8 μF cm−2, and a decrease of charge transfer resistance to 92.74 Ω cm2, which is mainly attributed to the PbO2 electrode modified with Tween 80, coupled with the synergistic effects of MWCNTs doping.

Modulating magnetic properties of high entropy soft FeSiB(P)Cu alloys with excellent GFA via α-Fe(Si) grain preferential growth mechanism

Modulating magnetic properties of high entropy soft FeSiB(P)Cu alloys with excellent GFA via α-Fe(Si) grain preferential growth mechanism

(10–13)-oriented semipolar GaN growth on (10–10) m-plane ScAlMgO4 substrate

Abstract We report the growth of a GaN layer on (10–10) m-plane ScAlMgO4 (SAM) substrate. The GaN layer demonstrated (10–13) preference growth orientation. The anisotropy of the crystalline quality was distinctly observed through X-ray rocking curve taken across the sample surface over various azimuths across the orthogonal directions [0001] and [1–210] of the SAM substrate. Notably, the crystalline quality exhibited gradual degradation as the substrate is rotated around its surface normal away from the c-direction [0001] of the SAM substrate toward the a-direction [11–20]. Additionally, basal stacking faults in the (10–13)-oriented GaN were observed along [0001] direction using scanning transmission electron microscopy. Moreover, the selected area electron diffraction analysis was utilized to confirm the (10–13) growth orientation that was found to be consistent with the X-ray diffraction result. The (10–13) GaN layer exhibited a metal face through integrated differential phase contrast imaging.

Morphology Regulation of Organophosphate Crystals by Micro‐Jetting Technique

AbstractOrganophosphates nucleating agents are widely used in the plastics industry. Nucleating agents with different morphologies have various effects on the resin materials. The micro‐jetting technique is shown to be a promising tool for the controlled preparation of micro‐and nano‐sized particles. Therefore, in this paper, controllable preparation of sodium 2,2'‐methylene‐bis‐(4,6‐di‐tert‐butylphenyl) phosphate (NA11) is achieved by the micro‐jetting technique. The study focused on the impact of various parameters on its shape and size. Hexagonal, rhombic, rod‐shaped, and needle‐shaped micro‐sized NA11 crystals are prepared. The results show that the decrease in the polarity of the organic solvents added in the antisolvent water led to the transformation of NA11 from bulk hexagon to plate‐like rhombus and finally to needle‐shaped crystals. The addition of surfactants can regulate the crystal growth rates and orientations, thereby facilitating the formation of rod‐shaped crystals. Based on rod‐shaped crystals, the crystal size is studied. Crystals with average particle sizes in the range of 40–100 µm can be obtained with coefficients of variation as low as 4% by varying the relevant experimental parameters such as the supersaturation, the solution homogeneity in the crystal growth environment, and the mixing intensity. This study provides references for designing functional materials.

Controlling of Crystal Facets by Dysprosium-Modified WO3/Carbon Nanofibers Enhance the Flexible Supercapacitor Performance.

Dysprosium-modified tungsten oxide/carbon nanofibers (Dy-WO3/PCNFs) are fabricated via electrospinning combined with high-temperature calcination to synthesize a flexible, self-supporting electrode material that does not require a conductive agent or binder. XRD and TEM analyses showed that introducing dysprosium promoted the preferential growth of WO3 crystals along the preponderance crystal planes involved in the electrochemical reaction, enhancing the exposure of the (002) and (200) crystal planes. Furthermore, DFT calculations demonstrated that the incorporation of Dy resulted in enhanced adsorption of Dy-WO3 by PCNFs, with an adsorption energy of -1.21eV. The Bader charge results indicate a transfer of 1.70 |e| from PCNFs to Dy-WO3. DFT calculations demonstrate that strong adsorption facilitates charge adsorption/desorption, which contributes to charge transfer and enhances storage capacity. The prepared Dy-WO3/PCNFs exhibited a high specific capacitance (557.28Fg-1 at 0.5Ag-1). Supercapacitors assembled with Dy-WO3/PCNFs as the positive electrode and CNFs as the negative electrode have high energy density (29.8Whkg-1 at a power density of 363.48Wkg-1). This study demonstrates the successful synthesis of Dy-WO3/PCNFs with exceptional electrochemical properties and offers significant insights into the design and application of flexible electrodes by incorporating dysprosium to modulate the crystal surface of WO3.

Psychological Predictors of Attitude toward Integrated Arts Education among Chinese College Students Majoring in the Arts.

This study investigated the psychological factors related to the attitudes of Chinese arts college students toward integrated arts education. It also examined predictive models incorporating psychological variables, demographic profiles, and art education-related characteristics to offer valuable insights for future research and art education practices. The sample comprised 303 Chinese college students majoring in arts and aged 18-22 years. The predictive models were examined using stepwise regression and decision tree analyses. The results indicated positive correlations between attitudes toward integrated arts education and several psychological variables, including extraversion, openness, conscientiousness, agreeableness, the Behavioral Inhibition System (BIS), hardiness, creativity, self-efficacy, and purpose orientation for personal growth. Neuroticism and the Behavioral Activation System (BAS) were negatively correlated with attitudes toward integrated arts education. Further, extraversion accounted for the greatest variance in attitudes toward integrated arts education. Extraversion, self-efficacy, purpose orientation for personal growth, BIS, and commitment accounted for approximately 38.3% of the variance. The decision tree model, predicting the attitudes of college students majoring in the arts toward integrated arts education, included extraversion, self-efficacy, teaching experience in their major, and academic year. This study contributes to a better understanding of the psychological and educational factors that shape the attitudes of Chinese arts students toward integrated arts education and provides a predictive framework that can inform future research and educational practices.

Constructing a multilayered film β[sbnd]PbO2[sbnd]ZrO2 electrode for energy-efficient zinc electrowinning

The zinc electrowinning process demands considerable energy, prompting the quest for energy-efficient solutions to curtail costs. Hence, the development of energy-saving anode materials for zinc hydrometallurgy is an important issue. Herein, multilayered PbO2 film materials were prepared through thermal decomposition and composite electrodeposition, yielding a new PbO2–ZrO2 electrode featuring ZrO2 particles as the second phase for energy-saving zinc electrowinning. The introduction of ZrO2 leads to reduced PbO2 crystal size, heightened the specific surface area of the electrode, and preferential growth of crystal planes. Electrochemical tests underscore that the PbO2–ZrO2 electrode manifests a reduced charge-transfer resistance (Rct) and overpotential alongside a 46.15 % extension in service life compared to the pure PbO2 electrode. Simulated zinc electrowinning experiment affirms PbO2–ZrO2 electrode has a 3.63 % surge in the current efficiency and a substantial 244.61 kWh/t reduction in energy consumption relative to the traditional Pb–0.6wt%Ag anode. This study provides a strategic framework for designing and developing cost-efficient, cost-effective anode materials, promoting advancements in energy conservation and consumption reduction within zinc electrowinning processes.

Bimodal structure formation and texture transition mechanism in laser remelted Mg–Al-based alloy

Texture inheritance, texture weakening, and a complete texture transition within different solidified molten pool (MP) have been achieved by manipulating various processing parameters of conduction mode in laser remelted magnesium-aluminum (Mg–Al)-based AZ31 alloy. At a low laser power (P = 100 W), restricted number of temperature gradient directions on moving solid/liquid (S/L) interfaces within small MP leads to strong texture inheritance. Tilting angles 20°–45° away from building direction (B.D.) in {0001} plane is a preferential growth direction of texture inheritance. In contrast, spontaneous texture weakening has occurred due to frequently varied temperature gradient directions within increasing MP size in higher P cases. Meanwhile, increasing scanning speed V has a significant effect on weakening the texture as well as refining grains in the solidified MP. Furthermore, fine grains formation with random orientations in MP bottom at both high P (400 W) and high V (20, 30, and 50 mm/s) leads to the occurrence of a bimodal structure, which is affected by solidification characteristics as well as thermal convection. For the case of the highest P and the highest V, a texture transition has occurred as tilting angles of 45°–90° away from B.D. in {0001} plane within MP, compared to 0°–45° texture of base material for the Mg–Al-based alloy in the study.

Impact of c- and m- sapphire plane orientations on the structural and electrical properties of β-Ga2O3 thin films grown by metal-organic chemical vapor deposition

Abstract This work presents a comprehensive investigation into the structural and electrical properties of Ga2O3 thin films grown via metal-organic chemical vapor deposition on both c- and m-plane sapphire substrates. Structural characterization revealed the β-Ga2O3 phase formation in both substrate orientations, with strong epitaxial ( 2 ¯ 01 ) preferential growth on c-plane substrates and polycrystalline films on m-plane substrates. Results show that Ga2O3/m-sapphire exhibits the lower electrical resistivity than its counterpart grown on c-sapphire. Activation energies of acceptor levels were estimated at ~1.4 eV and ~0.7 eV , for Ga2O3 films grown on c- and m-plane, respectively. This result shows that growing Ga2O3 on m-plane sapphire is beneficial to reach a weakly compensated sample. Cathodoluminescence analysis suggests that the additional low activation energy of ~0.18 eV observed in Ga2O3 grown with the highest oxygen flow on m-plane sapphire can be associated to thermally-induced migration of self-trapped hole states.

Greater TIMP-1 protein levels and neointimal formation represent sex-dependent cellular events limiting aortic vessel expansion in female rats.

Fragmentation/loss of the structural protein elastin represents the precipitating event translating to aortic expansion and subsequent aneurysm formation. The present study tested the hypothesis that greater protein expression of tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) and neointimal growth secondary to a reduction of medial elastin content represent sex-dependent events limiting aortic vessel expansion in females. TIMP-1 protein levels were higher in the ascending aorta of female versus male patients diagnosed with a bicuspid aortic valve (BAV). The latter paradigm was recapitulated in the aorta of adult male and female rats complemented by greater TIMP-2 expression in females. CaCl2 (0.5 M) treatment of the infrarenal aorta of adult male and female rats increased the in situ vessel diameter and expansion was significantly smaller in females despite a comparable reduction of medial elastin content. The preferential appearance of a neointimal region of the CaCl2-treated infrarenal aorta of female rats may explain in part the smaller in situ expansion and neointimal growth correlated positively with the % change of the in situ diameter. Neointimal formation was secondary to a significant increase in the density of medial/neointimal vascular smooth muscle cells (VSMCs) that re-entered the G2-M phase whereas VSMC cell cycle re-entry was attenuated in the CaCl2-treated infrarenal aorta of male rats. Thus, greater TIMP-1 expression in the aorta of female BAV patients may prevent excessive elastin fragmentation and preferential neointimal growth following CaCl2-treatment of the infrarenal aorta of female rats represents a sex-dependent biological event limiting vessel expansion secondary to a significant loss of the structural protein.

Nanocarbon-Polymer Composites for Next-Generation Breast Implant Materials.

Most breast implants currently used in both reconstructive and cosmetic surgery have a silicone outer shell, which, despite much progress, remains susceptible to mechanical failure, infection, and foreign body response. This study shows that the durability and biocompatibility of breast implant-grade silicone can be enhanced by incorporating carbon nanomaterials of sp2 and sp3 hybridization into the polymer matrix and onto its surface. Plasma treatment of the implant surface can be used to modify platelet adhesion and activation to prevent thrombosis, postoperative infection, and inflammation disorders. The addition of 0.8% graphene flakes resulted in an increase in mechanical strength by 64% and rupture strength by around 77% when compared to pure silicone, whereas when nanodiamond (ND) was used as the additive, the mechanical strength was increased by 19.4% and rupture strength by 37.5%. Composites with a partially embedded surface layer of either graphene or ND showed superior antimicrobial activity and biocompatibility compared to pure silicone. All composite materials were able to sustain the attachment and growth of human dermal fibroblast, with the preferred growth noted on ND-coated surfaces when compared to graphene-coated surfaces. Exposure of these materials to hydrogen plasma for 5, 10, and 20 s led to substantially reduced platelet attachment on the surfaces. Hydrogen-treated pure silicone showed a decrease in platelet attachment for samples treated for 5-20 s, whereas silicone composite showed an almost threefold decrease in platelet attachment for the same plasma treatment times. The absence of platelet activation on the surface of composite materials suggests a significant improvement in hemocompatibility of the material.

Growth Characteristics and Orientation Tuning of Superconducting Thin Films of Bi2212 Based on Substrate Orientation

Growth Characteristics and Orientation Tuning of Superconducting Thin Films of Bi2212 Based on Substrate Orientation

Photocatalytic activity of green synthesis ZnO nanoparticles from Chitosan and investigating the growth mechanism

In this study, we investigate the synthesis of zinc oxide (ZnO) nanoparticles using Chitosan, a bio-based precursor, with a green and sustainable production technique. ZnO nanoparticles are produced by magnetic mixing of Chitosan and zinc acetate in a solvent containing acetic acid and distilled water. The effects of chitosan on the growth mechanisms, morphologies and orientations of the particles during the formation of ZnO nanoparticles by heat treatment were examined at the molecular level. Another important focus of this study is the effect of round morphology ZnO nanoparticles on photocatalytic activity. The photocatalytic activity and optical properties of ZnO nanoparticles produced from measurements provided by UV–Vis analyzes are examined in detail.This research aims to assess the photocatalytic efficacy of ZnO nanoparticles in the degradation of methylene blue under visible light irradiation. An 88.05 % degradation is found during 90 min of irradiation under ambient conditions. The period of greatest degradation intensity was shown to be between 30 and 45 min.